ABAQUS in Scandinavia

Percutaneous Stent-Mounted Heart Valves

Fracture and Failure

Fluid Structure Interaction

Winter 2005

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As I write this article from our new headquarters office, I think about the many changes that have occurred over the past 13 years I have been with ABAQUS. I joined (then) HKS shortly after the company moved from the Medway Street office in Providence to the Main Street office in Pawtucket. So the move now to the Rising Sun Mills complex in Providence reflects not only the continuing expansion of our staff, both at headquarters and globally, but more importantly, the growth of ABAQUS software usage throughout the world.

As ABAQUS has grown throughout the years, so has the role of Product Management, and I am grateful to be associated with both. We view the ABAQUS Product Management function as essentially a link between you, our customers, and our talented and capable Development organization. We are seeking to capture your needs and requirements in the planning of what goes into each ABAQUS release.

The strong, general purpose capabilities ABAQUS possesses today make it well suited for a wide range of applications across many industries. These include not only automotive and aerospace, but a diverse range of others - consumer products, electronics, medical products, civil and offshore engineering are but a few (and your work may be in still another). Our challenge is to identify and implement those features and enhancements that have the broadest positive impact across the ABAQUS user base. I will brieflyoutline some of the steps that we, together with the ABAQUS CTO office and Development organization, are taking to do this.

First, we have an overall Product Strategy that guides our continuing development of ABAQUS. This Product Strategy looks forwardthree to five years, and is updated annually. It identifies workflows and technology areas that we are striving to address over the courseof several releases, and also includes a high level discussion of the development tasks we need to undertake to address these focusworkflows and technology areas. We engage closely with various customers to understand their workflows and what we need to do in

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IInn tthhiiss iissssuuee::1-2 Plotting the Future Course for ABAQUS Products

2 A New Home for ABAQUS Headquarters

3 ABAQUS Users� Conference 2005 - Stockholm, Sweden

4 ABAQUS in Scandinavia5-6 Investigating Possibilities for Percutaneous

Stent-Mounted Heart Valves at Edwards Lifesciences

7-8 Fracture and Failure: A Strategic Initiative at ABAQUS

BONUS Pull-Out ABAQUS 2005 Calendar8 ABAQUS Web Seminars

9-10 ABAQUS Services Spotlight - STRIX, Ltd.

10 Technical Corner

11-12 Fluid-Structure Interaction

12 ABAQUS/CAE Plug-ins

13 ABAQUS Partner Day

13 ABAQUS for CATIA V5

14 ABAQUS In the News

ABAQUS INSIGHTS is published by

Rising Sun Mills166 Valley Street

Providence, RI 02909-2499Tel. +1 401 276-4400Fax. +1 401 276-4408

info@abaqus.com

WWW.ABAQUS.COMCopyright 2004 ABAQUS, Inc.

All rights reserved.

Editor:Jeff Rankin

Contributors:Tom BattistiDale BerryKingshuk BoseKaren CurtisMilton DeHerreraStacy HartJan HernelindAsif KhanMark MonaghanDavid PalmerMarc SchrankJon Wiening

Production Coordinator: Laura Wistow

The following are trademarks or registered trademarks of ABAQUS, Inc. or its subsidiaries in the United States and/or other countries: ABAQUS, ABAQUS/Standard, ABAQUS/Explicit,ABAQUS/CAE, ABAQUS/Viewer, ABAQUS/Aqua; ABAQUS/Design; ABAQUS/Foundation;and the ABAQUS logo. Other company, product and service names may be trademarks or

service marks of others.

Plotting the Future Course for ABAQUS Products

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ABAQUS to meet the needs of these workflows. Our focus technology areas are driven also byengaging with various customers to understand their needs, as well as by taking a wide look at the FEA market overall.

At the same time, we pay close attention to �proximal� workflows, those that are reasonably close to our focus workflows in terms of their needed features and enhancements in ABAQUS.When carrying out development projects for a given release, we strive to ensure that the projectsare defined broadly enough that their deliverables also address the needs of the proximal workflows. Each development project we undertake has the role of Customer Representativeassociated with it. It is the Customer Representative�s job to make sure that the customers� needsare being addressed in the project. And the large majority of these Customer Representative roles are assigned to Product Management staff.

On a selected basis, we are using �Customer Review Teams� (CRTs) to provide key guidance andfeedback for particular initiatives we have underway. For example, the ABAQUS for CATIA V5CRT includes representatives from BMW, Boeing, Honda, PSA, Snecma, and Toyota, and hasbeen guiding the development of this new ABAQUS product for the past 2 ½ years. Anotherexample is the Fracture CRT. Made up of nine commercial customers from a range of industriesas well as a few academic customers, the Fracture CRT is helping drive our Fracture and FailureModeling technology area.

We also recognize that you have various �requests for enhancement� (RFEs) in ABAQUS that are important for you to improve the effectiveness of ABAQUS for your work. To better capturethese needs, we introduced the WebRFE system about 15 months ago. WebRFE accomplishestwo important objectives: it provides you the opportunity to submit RFEs directly for consideration in the planning of future ABAQUS releases; and it provides us a database to manage and track the wide variety and large volume of RFEs we receive - each RFE you submit is reviewed by both your local ABAQUS office or representative as well as someone in Product Management. We do our best to pay attention to RFEs when it comes to release planning; for example, more than 200 unique RFEs have been addressed in the upcoming release of Version 6.5.

Our Product Management team is working hard to strike the right balance in our ABAQUSrelease plans. We know from experience that by working closely with our customers, we canmutually achieve significant gains in finite element technology. At the same, we are always looking for ways to improve. I would be very pleased to hear from you regarding how we can do a better job of understanding your needs, either via email, or if you are in the vicinity, by visiting our new headquarters facility in Providence.

Marc SchrankDirector, Product Management

Presently, Marc leads the ProductManagement group at ABAQUS.He joined the company in early1992, first in the Enhancement and Support group, then movinginto the Marketing and Salesgroup. During this time, heworked with numerous ABAQUScustomers and prospects toexplore how ABAQUS could be utilized to solve their particular applications most effectively. Marc took on the role of ProductManager for ABAQUS/Explicit in 1998, and in 2001 transitioned to lead the overall direction of theProduct Management group. Prior to joining ABAQUS, Marcworked for nearly 10 years atAlliedSignal (now HoneywellFM&T) in Kansas City, Missouri,as part of an internal consultinggroup that provided FEA servicesto other engineering departmentsat this large manufacturing facility. During this time, hebecame involved with a variety of manufacturing-related simulation efforts, from weldingand brazing to metal forming and potting of electrical assemblies, many of these using ABAQUS. Marc earned a Bachelors degree inEngineering Mechanics from the University of Missouri-Rollaand a Masters degree inMechanical Engineering from the University of Missouri-Columbia, and is a licensedProfessional Engineer (P.E.).

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About Marc Schrank

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In November, ABAQUS relocated its headquarters operations from Pawtucket,Rhode Island to a new corporate campus located at Rising Sun Mills, a short distance south, in Providence, Rhode Island. Continued expansion of the company required the move to a larger facility.

Located in a riverfront complex of 19th-century Providence mill buildings that once produced the nation�s largest supply of worsted wool, the ABAQUS

offices at Rising Sun Mills combine a high technology environment with traditional values of solidity and reliability much like the previousABAQUS office, itself a former mill building. The campus is situated along the Woonasquatucket River, and is part of a major revitalization project in Providence.

�Our expansion to this larger facility is a tribute to the ABAQUS team, a vindication of our absolute focus on Finite Element Analysis, and atestament to our philosophy of taking exceptionally good care of our customers,� commented Mark Goldstein, President of ABAQUS. �I amexcited by what ABAQUS has accomplished since its inception and feel confident we will continue this progress in the years ahead.�

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The 18th annual worldwide ABAQUS Users� Conference will beheld May 18-20, 2005, in Stockholm, Sweden. The conferenceprovides a forum for ABAQUS users around the world to meetand share experiences, to discuss the capabilities of ABAQUS anddesirable enhancements to the software, and to examine issuesrelated to hardware and complementary software.

Technical sessions consisting of invited and contributed lectures by ABAQUS users will be held along with in-depth tutorials andpresentations by ABAQUS personnel relating to new or advancedfeatures in ABAQUS. This year�s event will again feature a technology pavilion where providers of ABAQUS-related productswill be on hand to explain how their offerings can help make youmore successful in your overall engineering process. A new featureof this pavilion will be the inclusion of several ABAQUS stations,situated among our alliance partner stations, where our technicalstaff will be available to demonstrate some of the new technologyand functionality presented during the conference and to discussyour ideas for future versions of ABAQUS.

ABAQUS is delighted to announce analysis group leaders fromNokia and Scania have agreed to join this event as our invited lecturers. We believe an overview of the exceptional work being performed with ABAQUS at these two companies will be of great interest to the ABAQUS user community and we are certain these presentations will be a highlight of the conference.

We will publish a bound set of Conference Proceedings for thisevent. In addition, we will provide an interactive CD with electronic versions of all presented papers, which will be mailed to all attendees after the event. To ensure that your paper appears in the published proceedings, you must provide final text and high-resolution graphics before March 1, 2005. We reserve editorial rightsin selecting papers for publication in the Conference Proceedings.

AccommodationsThe meeting will be held at the Hilton Stockholm Slussen, located in the heart of Stockholm, with wonderful views across the waters of Riddarfjärden to Stockholm City Hall and the OldTown (Gamla Stan). The conference venue offers a modern and efficient conference setting, perfect for rich and enthusiastic interaction and exchange of technical information and ideas with ABAQUS engineers and other attendees. ABAQUS hasreserved a block of rooms for attendees at the conference venue at special rates. To book your accommodations contact the HiltonStockholm Slussen directly and explain that you will be attendingthe conference.

Conference FeesAn early bird conference registration fee of �775 will be availableuntil February 15, 2005, after which the normal fee of �875 willapply. The conference registration fee includes all conferenceevents but does not include accommodations. A single presenter of an accepted paper will receive an additional �100 deducted from the registration fee. The day prior to the conference we willoffer the following tutorials on advanced topics in ABAQUS:

� Getting the Most From Your ABAQUS Contact Analyses

� Introduction to Fluid-Structure Interaction Simulation Using ABAQUS and FLUENT

� Advanced FE-Model Building with ABAQUS/CAE

� Modeling Fracture and Failure Effectively in ABAQUS

The fee for these tutorials is �350. Additional details on registering for the conference, including on-line registration, will be available shortly.

We hope you will attend and contribute to the success of this conference. To learn more, please visitwww.abaqus/com/AUC2005.

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Hilton Stockholm Slussen located in the heart of Stockholm, with wonderful viewsacross the waters of Riddarfjärden.

Paper Submission

Draft Manuscript: February 1, 2005 Final Manuscript: March 1, 2005

Final manuscripts must be emailed to conferencepapers@abaqus.com as well as two hard copies sent via standard mail to:

Attn: Laura WistowABAQUS, Inc.Rising Sun Mills, 166 Valley StreetProvidence, Rhode Island 02909-2499

Please include:� Paper (Word Office 2000 format)� Author info page (Signed pdf)

In order to reserve a speaking time at the conference, thepresenter of a contributed paper must meet all deadlinesand register for the conference by March 1, 2005. For questions, please contact Michele Rivard at +1 401 276 4420 or email: michele.rivard@abaqus.com.

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A reflection on the advent and growth ofABAQUS in Scandinavia

It seems appropriate this year�s worldwide ABAQUS Users� Conferencewill be held in Sweden; as several of the core capabilities of the ABAQUSproduct line were developed in partnership with our Scandinavian officeteam and through close collaboration with some of the region�s early customers. This article looks back over some of these developments and afew of the early steps taken by the Scandinavian office team to foster andgrow the presence of ABAQUS in Scandinavia.

Founded in 1983, the ABAQUS representative office FEM-Tech AB (FEM-Tech) was the first subsidiary of ABAQUS, Inc. At its inception,FEM-Tech was a three-way joint venture between ABAQUS, Jan Hernelind (the current General Manager of ABAQUS Scandinavia), and 3K, a Swedish consultancy company. (3K�s shares in the venture were eventually acquired in 1989.) Initially, this subsidiary was formed as a consulting company, with hopes of assisting in the sale of ABAQUS

software. ABAQUS Version 4.3 was the latest release at the time and, utilizing then current high-end hardware (a Floating Point Systems164, which also contributed significantly to heating the building), Hernelind set out to chart a course for ABAQUS in Scandinavia.

FEM-Tech�s first project was to develop the Linear Dynamics capabilities in ABAQUS, including modal dynamic, steady state, andresponse spectrum. After successfully completing this project, SAAB Automotive requested that random response be added. Successfuldelivery of this next capability helped forge a closer relationship with SAAB and naturally led to another request-to add Acoustics.Hernelind then worked closely with David Hibbitt to implement the early Acoustics capabilities in ABAQUS. Collaboration on development projects continued between FEM-Tech and ABAQUS in a number of areas, including dynamics modes for substructuring (an early project between Hernelind and Bengt Karlsson) and Jointed Materials and Infinite Elements (a project for Saudi Arabia involving Hernelind and Hibbitt).

The first consulting opportunity for FEM-Tech was with Aker, located in Norway. This first project developed into a long-term relationshipwith Christer Gustafsson, who currently serves not only as an ABAQUS business associate, but is also a vocal advocate for ABAQUS inthe offshore industry in Norway. Gustafsson continues to contribute outstanding presentations at the local Scandinavian Users� Meetings.

The year 1986 was witness to several significant events for ABAQUS in Scandinavia. FEM-Tech hired a second employee: Håkan Lind, a colleague of Hernelind�s from the past, joined the company. Håkan continues today at ABAQUS Scandinavia as a Senior Engineer,involved with support, training and consulting projects. FEM-Tech began working with Lennart Börgesson of Clay Technology AB, focusing on structures and processes for the safe storage of nuclear waste. The Swedish concept is to use tunnels in the rock where bentonite (clay) is packed around the canisters. Research in this area is ongoing; there is an experimental set-up in Äspö, close toOskarshamns Nuclear Plant, which requires simulations for several years to come. Finally, 1986 also saw the move of FEM-Tech from their offices in Hernelind�s garage to actual office space!

In the years that followed, JanAnders Larsson, who was providing consulting services within the building industry, began usingABAQUS-and so began a fruitful co-operation which lead to the development of the Brigade suite of software by Scanscot TechnologyAB, which Larsson helped to found. Another successful project has been ABAQUS Scandinavia�s consulting work to support the challenging task of developing an accurate material model for paperboard (used in milk cartons and other beverage containers). This project is finally coming to fruition after five years of intensive research and development, involving STFI (Sweden) and MIT (USA), as well as TetraPak, AssiDomän and StoraEnso (all from Sweden). In addition to the material model for paper �creasing analysis�, newfeatures in ABAQUS developed as part of the project include the UINTER/VUINTER user subroutines for interface properties.

From these beginnings in dynamics, offshore, and nuclear power engineering, to widespread adoption in ground vehicles, packaging and civil engineering, ABAQUS use in Scandinavia continues to accelerate technically and in terms of the number of users. ABAQUSScandinavia has two offices in Sweden (Västerås, head office, and Gothenburg) and one in Espoo, Finland (ABAQUS Finland Oy). Today, the seven employees of ABAQUS Scandinavia remain committed to the same fundamentals Hernelind set out for FEM-Tech at its inception-delivering high quality, accurate and innovative finite element solutions to design and manufacturing firms in the region.

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From left to right: Jan Hernelind, Anneli Dottemar,Jan Granlund, Gun Iwarson, Jonas Dyberg andHåkan Lind. Inset at right: Kari Saarinen.

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Investigating Possibilities forPercutaneous Stent-Mounted

Heart Valvesat Edwards Lifesciences

Numerical simulation using ABAQUS enables the study of multiple designs ina timely fashion reducing the need for costly benchtop and animal modeling.

According to the World Health Organization, an estimated 16.7 million people around the globe die of cardiovascular diseases(CVD) each year. Heart attack and stroke deaths are responsible fortwice as many deaths in women as all cancers combined. In 2001, CVD contributed to nearly one-third of global deaths. Noted in arecent American Heart Report, low- and middle-income countries contributed to 85 percent of CVD deaths.

In its current form, cardiac surgery is highly invasive and generallyrequires lengthy hospitalization. A principal objective in the MedicalDevice industry is to develop less invasive surgical procedures thatminimize the physical trauma incurred when making �repairs� to the cardiovascular systems. It is believed a collateral benefit of such procedures will be a significant reduction in a patient�s recovery time and ultimately, in healthcare costs.

About Edwards LifesciencesEdwards Lifesciences, a leader in advanced cardiovascular diseasetreatments, is a leading heart valve company in the world and theglobal leader in acute hemodynamic monitoring. Headquartered inIrvine, California, Edwards leverages its design, development, andmarketing expertise through four main product categories: HeartValve Therapy, Critical Care, Cardiac Surgery, and Vascular Therapy.In May of 2004 at the Worldwide ABAQUS Users� Conference,Edwards� team of engineers and medical professionals presented a paper entitled, �Finite Element Analysis of a Percutaneous Stent-Mounted Heart Valve.� In this paper and presentation, Edwards�team described how ABAQUS software has been used to accuratelypredict the structural behavior of varying design configurations,enabling Edwards engineers to determine whether or not a particulardesign concept was feasible.

Physiology and Materials ScienceAn important part of the Cardiovascular system is the Aortic Valve(AV) which, when it functions properly, efficiently helps transportthe freshly oxygenated blood from the heart�s right ventricle into thecirculatory system and prevents blood from flowing back into theventricle. The AV can become impaired as result of calcification andother chemical, physical, or biological mechanisms. In patientswhere an impaired AV leads to a severe cardiac deficiency, valverepair and/or valve replacement is generally called for. The currentmedical procedure for cardiac valve replacement requires an operation to open the chest (thoracotomy) and cardiopulmonarybypass (hookup to a heart-lung machine). Each year, an estimated300,000 patients worldwide undergo invasive open-heart procedures, and these procedures (thoracotomy and CP bypass) are neither practical nor recommended for patients who are of an advanced age, and/or are not in good health.

During the late 1990�s, the Edwards company undertook an effort toproduce a stent-mounted valve that could be delivered percutaneously,that is, through a blood vessel with an entry point being located ineither the femoral artery, the carotid artery or the subclavian artery.Any system that is to be delivered percutaneously must meet the following minimum requirements:

� The entire system must fit in a geometric envelope of outer diameter 20 - 24 French (6.66mm - 8mm).

� The system must have enough radial stiffness to remain in placeand maintain its circular shape after it is fully deployed.

� The peak tensile stress and strain during the device�s service life should be small enough so that material fatigue does not become a prosthesis valve performance issue.

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Also during the 1990�s, materials known as Shape Memory Alloys(SMA�s) emerged as offering a solution to materials challenges forthis application. In particular, the Nickel-Titanium alloy NiTinolshowed great promise because of its uncanny ability to undergolarge strains in its �soft� state and then revert back to its initialformed shape when the temperature of material was increased.

Design Concept: A Flat-Sheet Based StentOne of the proposed concepts for valve design for this prostheticaortic valve was based on using a NiTinol flat-sheet with tissueleaflets sutured onto its inner surface. The NiTinol flat-sheet wouldbe cooled down below its Martensitic Start temperature (Ms). It isrolled down to a smaller diameter and geometrically confined to a20 French size where it would stay until it was released into itsdeployed position, at which time the increased body temperaturewould cause a transformation into Austenite and thus revert theNiTinol flat-sheet back into its �original� circular shape. To ensurethe NiTinol flat-sheet could overcome the native calcification resistance, an inflatable balloon catheter within the lumen of theprosthesis would be dilated to press and pin the native leaflets backagainst the aortic annulus. The diseased native leaflets would be held in check by the now-cylindrical and slightly oversized prosthesis aortic valve, with the new valve leaflets working torestore normal aortic functions and cardiac outputs to the patient.

Stresses, Strains and StiffnessThe two principal questions that had tobe answered by this study were: (1)Which stresses and strains result whenthe NiTinol flat-sheet is rolled onto apin? and (2) Which is the radialstrength/stiffness of the deployed prosthesis? To analyze the roll-down of the flat-sheet prosthesis requiredusing advanced ABAQUS features likedouble-sided contact, self-contact andfinite sliding contact. As a result, it was decided that the best course ofaction was to use ABAQUS/Explicit for the roll-down simulation of the flat-sheet. ABAQUS/Standard was then used to study the effect of a radially inward pressure on the final, deployed configuration.

The roll-down of the flat-sheet was modeled by using onedeformable body consisting of approximately 5600 S3R and S4Relements with about 6100 nodes, one rigid body to simulate theinternal pin on which the flat-sheet is being rolled onto, and twoguiding rigid bodies. The analysis was run with ABAQUS/Explicit,using variable mass scaling to dictate an initial time increment of10-5 seconds (compared to an unscaled time increment of 4.9x10-8seconds). To verify that mass scaling was not excessive, a plot ofinternal and kinetic energy was generated confirming that the KE was well below the IE. The resulting peak tensile strains in critical areas at the end of the rolldown were within acceptablebounds, proving this design concept was feasible from a rolldownperspective. ABAQUS/Explicit was instrumental in the successfulsimulation of a fairly intricate contact problem.

Successful delivery and deployment of the prosthesis aortic valvewould result in the lower part of the prosthesis being located in the aortic annulus. It was intended that the prosthesis would be oversized with respect to the diameter of the aortic annulus to ensure its fixation. The radial strength of the deployed configurationcan be evaluated by applying a radially inward pressure on the lower part of the prosthesis, below the so-called �scallop line.�ABAQUS/Standard was used for this part of the study. Followingseveral analyses with various pressure load configurations, it wasobserved that the flat-sheet concept did not have as much radialstrength as other in-house competing designs. There was significantprosthesis ovalization at pressures as low as 0.049 MPa (7.07psi)and outright collapse at about 0.055 MPa (8 psi).

Expectations, Reality and DecisionsIt is well known from solid mechanics that the radial strength of shell structures depends on the R/t ratio, where R = shell radiusand t = shell thickness (see Donnell, 1976). The prosthesis geometryanalyzed had an R/t ~ 60; it was not anticipated that the radialstrength would be so low for this R/t. Without a change in the material specification, strengthening of the prosthesis could only be accomplished by increasing the shell thickness, which would in turn have worked against the 20-24 French roll-down size limitation. As a result, this design was not considered to be a likelycandidate for productization, and development was shelved beforeany significant testing efforts were spent by our company.

In summary, a two-pronged study of a flat-sheet based prosthesiswas made using ABAQUS/Standard and ABAQUS/Explicit. Usingthe ABAQUS NiTinol superelastic material model the Edwardsengineers were able to show that the strains resulting from the roll-down of the prosthesis were within acceptable bounds.However, using the same numerical tools they found that the prosthesis was deficient in radial strength. Thus, through the use of ABAQUS they were able to show the inadequacy of this designwithout extensive and costly testing efforts in the benchtop and animal models. Finally, it should be noted that in further work using the ABAQUS suite of analysis tools, they were able to identify a design that provided superior mechanical performance.

TToo LLeeaarrnn MMoorreeYou may download the complete contributed paper given by Edwards Lifesciences at the 2004 AUC by visitingwww.abaqus.com/Insights-0501.

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About the Author: Originally from the DominicanRepublic, Milton DeHerrera attended the Illinois Instituteof Technology (Chicago, IL), where he received a BSCE and MSCE. He then obtained an MS in EarthquakeEngineering and a PhD in Civil/Structural Engineeringwith a minor in Applied Mechanics at Stanford University(Stanford, CA). He has worked at several engineering, consulting, software development and manufacturing firms, most recently at Freudenberg-NOK in Manchester,New Hampshire and has been at Edwards Lifesciences inIrvine, CA for the past 2-1/2 years.

Maximum tensile strain, LEP3,(mm/mm) during flat-sheet stent roll-down, displayed on undeformed configuration.

s

-5 -8

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In a society that is making rapid technological innovations in thefields of manufacturing and materials, there is a strong need tocreate designs that maximize the safe operating life of structuralcomponents. Manufacturers often need to answer:

� How long will a product last?� If it breaks, where and how will it fail?� Is the design �fail safe?�� What is the safe operating life of the product?� What can be done to extend the safe operating life?

Fracture and failure modeling addresses these real world concerns.Given the needs of the engineering community, we believe thatwithin five years damage and failure simulation will be as heavilyused as nonlinear material models are today.

ABAQUS leads the industry in support of capabilities formodeling damage and failure. Existing capabilities such as the contour integral, mixed-mode stress intensity factors, T-stress, failure models, etc. have been successful in providing customers the ability to assess the integrity of structural components. In spite of this success, we see a continuing need for advanced yeteasy-to-use capabilities that will allow our customers to include fracture and failure in their everyday simulations.

Over the past two years, we have embarked on a strategy to effectively tackle the area of fracture and failure in a comprehensiveway, considering both ease of use and technology issues. ABAQUSVersion 6.5 includes the first results of this initiative. The objectiveof this article is to provide some background on how we are tacklingthis challenge and to provide an overview of the fracture and failurecapabilities in ABAQUS Version 6.5.

To provide our development team with guidance and direction concerning necessary capabilities, we formed a Fracture CustomerReview Team (CRT). The Fracture CRT consists of leading companies from a variety of industries actively involved with modeling these kinds of problems. The goals of the team aretwofold: (i) identify and prioritize needed enhancements tofracture/failure capabilities; and (ii) help our team test the resultingenhancements to ensure they meet the needs of the user community.In addition to the Fracture CRT, input from other customers (throughthe RFE system) has also guided our strategy.

ABAQUS Version 6.5 offers the following major new capabilities inthis area:

� ABAQUS/CAE support for existing and new functionality� New material damage models� Compliant fasteners with damage� Cohesive Elements� Virtual Crack Closure Technique (VCCT)� Wear and Erosion

These capabilities are briefly outlined in the following paragraphs.

ABAQUS/CAE provides full support for the creation of cracks (including seams) and setting up all the ingredients needed forrequesting contour integral output. This includes special treatment

of the mesh around the crack tip which may be required for defining singular elements, defining crack-front, crack-tip, and the virtual crack extension direction.

As part of the overall effort to model damage, we have developed anew general framework for modeling damage and failure. Thisframework consists of dividing the material response into three components: (i) undamaged response; (ii) a damage initiation criterion that defines the onset of degradation of material properties;and (iii) a damage evolution criterion that defines progressive damage from initiation to a complete loss of stress carrying capacity.Upon complete degradation, an element may be removed. The modeling of damage evolution has been developed such that meshsensitivity is minimized. Specific enhancements within this generalframework include new models in ABAQUS/Explicit for ductiledamage, shear damage, and localized necking in sheet metals usingforming limit diagrams. A general capability, known as theMarciniak-Kuczynski analysis that numerically predicts the onset of necking in sheet metals has also been integrated intoABAQUS/Explicit.

Different damage initiation criteria on an aluminum profile.

Fracture and Failure: A Strategic Initiative at ABAQUS

7

ABAQUS/CAE Version 6.5provides significant new support for fracture, includingcreation of seams, crackfronts and tips; definition ofcontour integrals, and easy visualization of contour integral results. This figureshows a seam in a platemodeled in ABAQUS/CAE.The mesh at the crack tip isfocal and the elements on the two sides of the seam(shown in purple) are disconnected.

Forming limit Ductile Shear

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Starting in ABAQUS Version 6.5, fasteners can be defined as compliant (previously they could only be modeled as rigid). The general framework described above can be used to define progressive failure of fasteners. The response of fasteners may be defined as rigid-plastic with hardening dependent on the mode of loading (ratio of the normal to tangential force on the fastener).Mode-dependent damage initiation and evolution criteria may alsobe defined.

A family of cohesive elements has been introduced in ABAQUSVersion 6.5. These elements can be used for detailed modeling of the deformation and damage of adhesive layers at interfaces betweenbonded parts. Applications include finite-thickness, as well as zero-thickness adhesive between two parts. In the former case, the constitutive response of the adhesive layer may be defined in terms of any available material model in ABAQUS, while in the latter case, the constitutive response is directly defined in terms oftraction versus separation at the interface. Modeling of progressivedamage may be carried out within the general framework, withcapabilities to specify strong mode-dependence.

The Virtual Crack Closure Technique (VCCT) is a method for modeling crack growth under mixed mode conditions. Boeing has selected ABAQUS to commercialize their proprietary implementation of VCCT. This capability will be available in the first quarter of 2005 as an add-on to ABAQUS Version 6.5called �VCCT for ABAQUS.� ABAQUS�s implementation ofBoeing VCCT technology will broaden its applicability within the aerospace R&D and design community.

ABAQUS/Standard now has a capability formodeling material loss dueto surface wear and erosion.Typical applications include modeling wellbore sand production, solid propellant/ablation tire or disk brake wear, and machining. The extentor rate of material wear may be defined by the useras a mesh constraint usingthe adaptive mesh framework. A new user

subroutine, UMESHMOTION, with access to material point, nodal,or surface quantities is provided to allow the definition of wear forgeneral boundary shapes.

In closing, modeling of fracture and failure is a strategic area ofdevelopment at ABAQUS. The new features constitute a significantstep towards a more general capability for modeling these classes of problems. The Fracture CRT along with other customers are vigorously driving the development effort. This effort will continueover the next few years to help consolidate our position as a leaderin this area.

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Typical application using cohesive elements - modeling of debonding across a skin-stringer interface using ABAQUS/Standard Version 6.5.

The Virtual CrackClosure Technique

(VCCT) can be used todetermine global

strength and failuremode for aerospace

structures such as thisskin-stringer panel.

Image courtesy of BOEING.

AABBAAQQUUSS WWeebb SSeemmiinnaarrss

February Simulating Fluid-Structure Interaction with ABAQUS and FLUENT

March Small Engine Analysis with ABAQUS and AVL

April Highlights of ABAQUS Version 6.5

May Fracture/Failure Modeling in ABAQUS Version 6.5

June Contact Enhancements in ABAQUS Version 6.5

For details on upcoming web seminars and for replays of past web seminars, visit our website at www.abaqus.com/events. Please send us your suggestions for future web seminar topics as well as your thoughts for improvement by emailing: webinars@abaqus.com.

Bolt-down loading of the cylinder head of a model aircraft engine. Model geometry courtesy of PTC.

Fluid velocity dependent wear of a wellbore.

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As some of you know, ABAQUS provides a wide range of engineering services to our customers, complementing our software suite with the industrial experience of our engineers and their depth of problem solving knowledge. In addition to traditional support and training services, we regularly deliver consulting projects: to solve particularly complex design or analysis problems; to develop customized user routines or GraphicalUser Interfaces (GUI); and to help you conduct assessments toimprove your current methods or computing performance.

STRIX, Ltd. designs, develops, and manufactures heating elementsand the control units used in kettles. They decided to use analysis toreduce the number of �make it/test it� design iterations and acceleratethe design process. An automated design tool enabled designers tocreate geometry, meshes, and boundary conditions based upon theinput parameters entered through a GUI interface.

SSppeeeeddiinngg TThheerrmmaall SSiimmuullaattiioonnssIn working with STRIX, this project was devised to providedesign engineers with an analysis tool to create simulations of thethermo-mechanical performance of an electrical heating elementfound in a kettle/mocha maker. In a three week period that includedon site product orientation, process implementation and the finalhand over, the system was designed, developed and deployed, using ABAQUS/CAE and its Scripting Interface and GUI Toolkit.

Analysis RRequirements && TTypical SSolutionsIn the typical analysis of a kettle/mocha maker there are three components that are welded or brazed together:

� heating element� base plate or spreader� outer wall or body

The meshes of the components (including the spiral element attached to the spherical surface of the base) are based upon parameters defined in the interface. Materials are assigned to specific regions of the model by selecting the information from drop down lists. These lists are populated withmaterials saved within a materials database. Jobs are submittedinto a directory structure that allows easy reference to previousjobs and prevents accidental overwriting of historical data.

Both heat transfer and coupled thermo-mechanical analyses are

created through the interface.Water is driven through the coffee by the pressure of thesteam in the cavity. The pressure will affect the

temperature of the water. The user defines the operating

pressure, from which the systemcalculates a suitable surface temperature for the boundary condition.

AAnnaallyyssiiss CCoonnddiittiioonnss From the analysis system, it is possible to create a number of different types of analyses for the same geometry. Each type corresponds to a test or fault condition which the device must pass.

Rolling BoilThe device is considered to be full of boiling water and leftswitched on. This is a steady state analysis used to determine typical operating temperatures for the filament in the element and the outer surface of the body.

Dry Switch On (DSO)In this analysis, the device is empty when the power is switched on; it is considered a fault condition. Temperatures at key points (ie: the braze between theelement and the body) are monitored during the transient analysis.

Angled Boil to DryIn this case, also known as a fault analysis, the base is no longerresting on a flat table. The body is initially full of water that onlybarely covers its base. A steady state analysis is performed in thisconfiguration, before the water is allowed to evaporate away, hence, reducing the level of the water, during a transient analysis.

The time at which critical components of the control system reach their activation temperature is affected by the tilt of thebase. This is often one of the more severe tests performed.

AABBAAQQUUSS SSeerrvviicceess SSppoottlliigghhtt - SSTTRRIIXX,, LLttdd..

The parameterizedinterface allowsthe engineer toquickly define the geometry.

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The temperatures on the insideand outside of the device for arolling boil test.

Typical electrical heating elements manufactured by STRIX.

A typical temperaturedistribution seen during a DSO.

The temperatures seenduring an angled boil to dry simulation (modified geometry).

A cross section through the wall and base of a typical assembly.

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In Version 6.5 of ABAQUS/Standard and ABAQUS/Explicit,connector elements can be used to model mesh-independent fasteners. With this capability, the fastener can be deformable or rigid and can include the effects of damping, plasticity, damage, friction, and, in ABAQUS/Explicit, failure.Additionally, unconstrained relative motion in local connector components can be simulated. The general features of connector elements allow complex fastening methods to be approximated with point-to-point connections.

For example, consider theABAQUS/Explicit drop-testsimulation of a cordless computer mouse. The model is shown in figure to the left. Adrop of one meter is considered,with the mouse landing directlyon its nose. The base, middle

and upper housings of the mouse are joined with connector-based mesh-independent fasteners, as shown in the figure to the right.

The joining mechanisms are modeled with Cartesian and Cardan connector elements with a force-based failure criterion. The remaining components are joined using mesh tie constraints.

A five millisecond event is simulated. The last figure depicts the model at the end of the simulation; the force of impact hascaused the connectors to fail. In this example, all components of connector relative motion are released when the failure criteria is met; the upper, middle and base housings thus become completely separated.

In early January, a new Technical Brief will be available fordownload at www.abaqus.com/solutions/tech_briefs.html.

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Location of connector-based fasteners.

ABAQUS AnswersAn important part of the ABAQUS Online Support System (AOSS) is ABAQUS Answers: a knowledge base of answers to questions about using ABAQUS. Sinceits inception, the ABAQUS Answers knowledge databasehas grown steadily in its size and use, with well over 650different answers on a wide variety of topics.

Two answers were recently added to the knowledge base insupport of the new surface-to-surface method for enforcingmesh tie and small sliding contact constraints introduced inABAQUS Version 6.5. This approach optimizes resultsaccuracy and does not lead to stress oscillations at the constraint interface. The behavior of this formulation differs from the node-to-surface formulation in two ways:performance and cost. ABAQUS Answers 2190 and 2192address the details:

2190 Understanding position tolerance with true surface-to-surface tie constraints

By virtue of the difference in formulations, the surface-to-surfaceapproach may involve more slave nodes in a given constraint thanthe node-to-surface approach. Answer 2190 discusses the details of how different tolerance regions are used for the two constraint formulations.

2192 Using the surface-to-surface method for mesh tie constraints and small sliding contact

For a given constrained slave node, more master nodes are involvedin enforcing the constraint than in the node-to-surface approach.Answer 2192 discusses the trade-offs between accuracy and costassociated with the two methods.

To view the available ABAQUS Answers, log onto AOSS atwww.abaqus.custhelp.com and click the ABAQUS Answers tab.

If you have not created an AOSS account, follow the link for new users.

Mouse at end of simulation,showing separation of housing components.

Cordless mouse model.

CCoonncclluussiioonnThe ABAQUS Scripting Interface and GUI Toolkit have beensuccessfully deployed at STRIX to provide powerful designtools to non-FEA experts. Embedded within the scripts are current best practices and methods developed by ABAQUS UK.

More information and examples from our portfolio are availableat: www.abaqus.com/Services. For more information or to notean ABAQUS Services experience in a future Insights article, callyour local ABAQUS office or email: services@abaqus.com.

Thanks to ABAQUS UK Ltd., STRIX Ltd., and petra-electric.

This stylish mocha coffeemaker from petra-electric utilizes the latest STRIX Technology. Image courtesy of petra-electric.

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Fluid-Structure Interaction (FSI) encompasses the very broad scopeof problems in which fluid flow and structural deformation interactand affect one another. The interaction may be thermal, mechanical,or both, and can be steady or transient. Many important problemsinvolve some form of FSI, but the coupling effect is often ignoreddue to lack of readily available solution technology.

To address this limitation, Fluent and ABAQUS have partnered onan initiative to provide a coupled solution using ABAQUS andFLUENT. Fluent is a CFD market leader in many regions and industries. Like ABAQUS, Fluent has a strong focus on technology and quality. Throughthis joint initiative, we are providing engineers with proven,easy-to-use tools that take intoaccount important coupling effects,including sophisticated simulationof nonlinear structural responseand complex fluid flow. The co-simulation capability is expected to address applicationssuch as thermal stress prediction in exhaust manifolds, design ofvalves and rubber diaphragms that restrict fluid flow, micro-fluidics, in-vivo vascular flows, as well as many design and packaging applications.

The ABAQUS-FLUENT FSI software suite consists of three maincomponents: ABAQUS, FLUENT,and MpCCI, as shown in the schematic. MpCCI (Mesh-based parallel Code Coupling Interface) is an application-independent interface for the coupling of different simulation codes. MpCCI is aproduct of the Fraunhofer Institute for Algorithms and ScientificComputing (SCAI), one of 58 institutes within the Fraunhofer Society, a German research organization for applied and industrialR&D. We chose MpCCI to provide the coupling between ABAQUSand FLUENT because MpCCI is rapidly becoming an establishedstandard for enabling robust, scalable multi-vendor coupled solutions.In addition, MpCCI currently supports code coupling between manyother simulation products, providing our customers the capability tocouple other codes to ABAQUS via MpCCI.

We are enthusiastic about this capability and believe this partnership with Fluent and Fraunhofer SCAI offers many advantages to our customers. In addition to offering best-in-class structures and fluids capability, this new capability allows relatively independent setup of fluid and structural sub-problemsusing proven tools from ABAQUS and Fluent. In addition, thefamiliar solution algorithms within each domain can still be used.Finally, code coupling will be based on industry-standard scalableinter-process communication and mapping tools (MpCCI).

The ABAQUS FSI capability (the co-simulation interface plus theABAQUS/MpCCI Plug-in) will be delivered completely within the

Version 6.5 release - no additional software, license supplements, or fees will be needed from ABAQUS, although one additionalanalysis token will be required to run FSI problems. FSI will beavailable in both ABAQUS/Standard and ABAQUS/Explicit inVersion 6.5. The FLUENT FSI capability (consisting of the FLUENT/MpCCI Plug-in plus a library of �libudfs� - the equivalentof user-subroutines in FLUENT) will be based on FLUENT Version6.2 scheduled for release late January 2005 and will require the user to obtain the separately licensed FLUENT/MpCCI Plug-in from Fluent. MpCCI Version 3.0 is also required and is available separately from Fraunhofer SCAI. Although each party will license

and distribute its own products, wehave entered into mutual worldwidetechnical support agreements toensure customers get qualified and timely assistance in installing,verifying and utilizing the FSI software suite. Finally, note that all three programs -ABAQUS,FLUENT, and MpCCI - utilizeFlexLM-based licensing, so licensing operations for FLUENTand MpCCI will be familiar toABAQUS users and their IT groups.

The solution of multi-disciplinary problems like FSI will be a new and challenging area for manyABAQUS users. Since expertise in both ABAQUS and FLUENTis needed to solve FSI problems, we believe that FSI problems will

often be solved jointly by teams of two or more engineers with collective experience in both ABAQUS and FLUENT. In time, individual ABAQUS users may develop the necessary expertise inFLUENT, but if you do not have such expertise, you can obtain it through FLUENT training or by working with your CFD colleagues to solve FSI problems with the ABAQUS-FLUENTcapability. Therefore, if your company is already a strong jointABAQUS and FLUENT customer with in-house FLUENTexpertise, you will find the FSI capability in ABAQUS Version 6.5to be a natural extension of your existing ABAQUS FEA and FLUENT CFD simulation capabilities.

In order to use the FSI capability in ABAQUS Version 6.5, userswill begin an FSI simulation by developing a FLUENT CFD modelwhich runs properly in FLUENT and by developing a separateABAQUS structures model which runs properly in ABAQUS,before joining the two models using the FSI capability. The common boundary between domains in these models must be placed at the same spatial location in each model, but both of thesesingle domain models will necessarily use assumed values for theinteraction variables passed across these boundaries. Once thesemodels work properly and are then interconnected through the FSIcapability, these assumed values will be calculated by the other code and transferred between domains using MpCCI.

FFlluuiidd-SSttrruuccttuurree IInntteerraaccttiioonn

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FSI Co-Simulation Components

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ABAQUS users taking advantage of the Process Automation tools (ABAQUS Scripting Interface and the ABAQUS GUI Toolkit)frequently want to include utility functions that they have developed into ABAQUS/CAE. The plug-ins� infrastructure in Version 6.5of ABAQUS/CAE provides an exciting new feature to customers for including multiple customizations in ABAQUS/CAE. As a result,you can customize ABAQUS/CAE without creating a vertical application and can provide a user interface that is launched from thenew Plug-ins menu.

You can use ABAQUS/CAE plug-ins to improve your productivity and create a variety of custom tools for automating specific tasks.Plug-ins execute ABAQUS Scripting Interface and GUI Toolkit commands and provide a convenient way to customize ABAQUS/CAE for your particular workflows or preferences. Existing custom applications can be easily converted into a plug-in using a straightforwardprocedure outlined in the ABAQUS/CAE manual. The following plug-ins are provided as examples with ABAQUS/CAE Version 6.5:

� Running the �Getting Started with ABAQUS� examples � Creating a GUI plug-in � Creating a kernel plug-in � Displaying mode contribution factors

In the site directory, you can install a plug-in and make it available to every user at your site. Alternatively, you can install a plug-in in your home or current directory, and it will not be visible to other users. The ABAQUS ProcessAutomation Portal contains a number of plug-ins available to ABAQUS users for download and additional plug-ins will be available. Existing plug-ins can beenhanced to fit particular requirements and also serve as templates and provideideas for new plug-ins that you may want to create.

One attractive feature of plug-ins is the ease with which they can be included inABAQUS/CAE and shared-installing an existing plug-in merely consists of placing the plug-in files in the designated directory. We encourage you to takeadvantage of this exciting new functionality.

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A screenshot of ABAQUS/CAE Version 6.5 showing the plug-ins menu with a number of plug-ins included.

To help ensure the success of our customers in using ABAQUS-FLUENT FSI, the FSI capability in the initial release of ABAQUSVersion 6.5 will be �controlled.� Your local office will help you determine if your FSI problem is applicable for this new ABAQUS-FLUENT FSI capability. Moving forward, your local office will help you understand how to obtain the needed software components,as well as enable the capability once you are ready to begin the ABAQUS-FLUENT simulation.

Here is a brief example of the many applications where the FSI capability can be used to add value and accuracy to the simulation:

Exhaust Manifold Thermal-Stress Prediction ExampleStarting a car when it is cold induces significant thermal stresses in the exhaust manifold. Its durability depends on the magnitude of the extreme stress cycle. The mechanical constraints (bolts, gaskets) can increase local stress, while materialcreep/plasticity further contributes to the complexity of the analysis. Inclusion of heat transfer to and from the hot exhaust stream and manifold is critical to understanding thermal stress histories.

The model includes cast iron material properties, an initial temperature condition of22°C representing a cold start, an instantaneous hot gas flow with an inlet temperatureof 650°C, and an external film coefficient on the outside of the manifold.

As shown in the graphic at right containing fluid velocity vectors and structural temperature contours in the manifold, theABAQUS/Standard-FLUENT FSI solution provides more realistic temperature profiles and histories in the manifold than current practice. This capability will also be applicable to water jackets, coolant flow, circuit board, and turbine blade cooling problems.

For more information on this new capability, please visit our website at www.abaqus.com.

Image created with Ensight Gold from CEI

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On October 14, 2004, ABAQUS hosted its second Partner Day at its headquarters in Rhode Island. Partner Day has proven to be an effectivevenue for ABAQUS to share information with alliance partners about the company, our product roadmap, initiatives, and for ABAQUS to learn more about its alliance partners. Partner Day also provides an excellent atmosphere for the exploration of mutual sales and marketing and technology opportunities between ABAQUS and its alliance partners as well as for the open exchange of market perceptions, trends, directions, and technology challenges that we collectively face. Furthermore, alliance partners are given the opportunity to voice their suggestions for enhancing the Alliances Program and our products to help meet their business needs.

ABAQUS welcomed 36 attendees at Partner Day representing the following companies: AEA Technology, AMD, Ammasso, AVL List GmbH, CEI, CM Beasy, Coventor, Elysium, Exa Corporation, e-Xstream engineering SA, Fluent, First Technology Safety Systems, FujitsuAmerica, Hewlett Packard, IBM Corporation, Intel, Linux Networx, LMS International, Maya Heat Transfer Technology, NEC, NVIDIA Corporation, SGI, Simmetrix, Simulog TechnologiesSA, Spatial Corporation, Tecplot, and UGS.

Lee Fisher, HP CAE Worldwide Business Manager, commented, �ABAQUS Partner Day convinced me that ABAQUS has set a high standard for the CAE community in defining an effective partner program. Their software and hardware partnerships are taken seriously and deliver value to our common customers. I found the event especially worthwhile because I was able to network with ABAQUS as well as a host of other attendees with whom HP also partners.ABAQUS� vision of unified FEA is compelling, especially if a mechanism for creating an open,standard data model can be identified. I look forward to attending next year�s Partner Day.�

�Partner Day was a great success from the perspectives of both ABAQUS and the attendees,� remarked Tom Battisti, Manager of the AlliancesProgram at ABAQUS. �We are confident Partner Day will continue to grow in popularity and we envision it becoming a premier annual event.�

AAbboouutt tthhee AABBAAQQUUSS AAlllliiaanncceess PPrrooggrraammABAQUS has established strong relationships with over 85 independent software and hardware alliance partners. Through these alliances wedeliver technology that further differentiates ABAQUS, ensures interoperability and robustness with leading MCAE and MCAD tools and hardware platform configurations, in turn increasing customer productivity. Our goal is to allow customers to more fully leverage their investments in ABAQUS software. Together, ABAQUS and our alliance partners are striving to provide best-in-class solutions for your design, simulation, and product development needs. If you would like to learn more about the ABAQUS Alliances program or our partners,please visit our website at www.abaqus.com/alliances.

AABBAAQQUUSS PPaarrttnneerr DDaayy

Tom Battisti, Alliances Manager, and BarbaraHutchings, Fluent, Inc.

With the release of Version 1.2-2, ABAQUS for CATIA V5 has become an effective tool for analyzing composite skin-stringer panels used in the aircraft industry. The geometry-basedmodeling paradigm supported by ABAQUS for CATIA V5 naturally allows changes in variousdesign variables, such as ply lay-ups and stringer section geometry and location, to be easilypropagated from the CAD model to the associated finite element model. The robust nonlinearcapabilities in ABAQUS enable the sophisticated analyses that are subsequently carried out toassess the structural integrity of the panel.

The model shown here is a skin-stringer testpanel similar to those used in an airplane or helicopter fuselage. These panels are often builtup from composite laminates to maximize theirstiffness-to-weight ratio. One of the importanttests performed on such a panel is an axial

compression test to determine its maximum loading capacity. By modeling a wide range ofvariations in skin-stringer panel design, aerospace companies can design optimal panels forthe entire aircraft.

UUllttiimmaattee LLooaaddiinngg CCaappaacciittyyIn the axial compression analysis, the panel is clamped at one end and compressedalong its axis from the other end. Because of their design, these panels tend toexperience localized buckling behavior long before reaching their ultimate loadingcapacities. The automatic stabilization feature in ABAQUS, requiring no userintervention, handles this localized buckling behavior effectively, thus enabling an assessment of the ultimate load capacity.

Skin-stringer test panel modeled with compositecomponents.

Axial compression loading. The goal of this analysis is todetermine the panel�s ultimate loading capacity, which occurs

long after buckling has occurred in localized regions.

AABBAAQQUUSS ffoorr CCAATTIIAA VV55 AAddddrreesssseess CCoommppoossiittee PPaanneell WWoorrkkfflloowwss

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Recently, several ABAQUS customers and employees were featured in major articles in a wide range of engineering publications. Several of these noteworthy articles are summarized below. To read the full stories, please visitwww.abaqus.com/News and click on �In the News.�

Medical DesignJuly/August 2004, pp. 24-30Simulating Bones, Bronchi, and Exotic Stent MaterialsFEA analysis has become an integral partof medical research as simulation modelsare used to understand the materials ofthe human body and to support the development of medical products. Thisarticle, written by Paul Dvorak,Managing Editor of Medical Design,describes how ABAQUS software developers worked with materials experts to characterize the properties of Nitinol, a shape-memory alloy used inthe production of stents.

Designfax September 2004, pp. 22-25Nonlinear Micro Finite Element Analysis of Human Trabecular BoneHarun H. Bayraktar, Technical SupportEngineer at ABAQUS, contributed atechnical paper describing the use ofABAQUS/Standard to perform a nonlinear analysis of human bone behavior. The study explores new territory, since previous approaches to studying the mechanical behavior of trabecular bone have required custom code and linear analysis. Harun joined ABAQUSfrom UC Berkeley, where his research concentrated on themechanics of bone tissue and the use of finite element methods to determine the elastic and plastic properties necessary to study the nonlinear behavior of human bone.

Automation WorldOctober 2004, p. 36Simulation Is Routine at GM and P&GProcter and Gamble is a veteran user of simulation in its manufacturing processes. In this article, David Henning, Manager of Package Analysis for P&G, describes the company�s�plug-and-play� simulation system for automated bottle analysis.Based on ABAQUS and Hypermesh software, the system helpsP&G sites all over the world save time and cost in packageanalysis. Mr. Henning was kind enough to support our recentWebinar on the topic of Consumer Products, presenting anoverview of P&G�s �VPS System�, a Process Automation application which uses ABAQUS for bottle design and simulation. To view a replay of this Webinar visit:www.abaqus.com/replay.

Desktop EngineeringOctober 2004, pp. 30-33Moving Up to Multiphysics AnalysisDale Berry, Manager of Engineering Applications at ABAQUS,contributed his opinion to this article examining the advantagesof multiphysics analysis. On the question of whether using multiphysics software offers better accuracy, better usability, and better economy than using separate FEA packages for each environment, he emphasizes that companies have to

define their specific analysis needs.�Although tight integration is a benefit,� he says, �it often comes at the expense of modeling and solution capability. Often, the tightly integrated solutions are more limited in each domain than separate packages.�

Advanced CompositesBulletinOctober 2004, pp. 8-11Technology Trends: FractureMechanics Software from ABAQUSand Boeing Extends Virtual TestingPotential for CompositesThis article explains why the move by Boeing Intellectual PropertyBusiness to license its implementationof the Virtual Crack Closure

Technique (VCCT) to ABAQUS will give aircraft designers more insight into

the fracture mechanics of advanced composites. Writer VickiMcConnell extensively quotes Dale Berry, Manager ofEngineering Applications at ABAQUS, who discusses the potential of the new VCCT software to advance understanding of composite damage tolerance and failure modes. The articlealso includes comments from senior scientists at the NationalInstitute of Aerospace and the Federal Aviation Administration.

Design News October 25, 2004, pps. 57-60How to Deal With a Nasty, Nonlinear ProblemBased on his extensive experience in nonlinear structuralmechanics, Ted Diehl, Ph.D, of DuPont Engineering Technology, describes his four-step approach to nonlinear design challenges. His steps include: determine what you know; decide if modeling can help; characterize the material; and validate the model. Confronted with the task of improvingthe design of an inflatable containment system supported by a polymeric non-woven envelope, Ted tested his approach, andexplains his solution successes.

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ABAQUS, Inc.Rising Sun Mills166 Valley StreetProvidence, Rhode Island 02909-2499+1 401 276 4400e-mail info@abaqus.com

Europe+31 43 356 6906e-mail info.europe@abaqus.com

Japan+81 3 5474 5817e-mail info.japan@abaqus.com

WWW.ABAQUS.COM

ABAQUS, ABAQUS/Standard, ABAQUS/Explicit, ABAQUS/CAE,ABAQUS/Viewer, ABAQUS/Aqua, ABAQUS/Design,ABAQUS/Foundation, and the ABAQUS logo are trademarks orregistered trademarks of ABAQUS, Inc. or its subsidiaries in theUnited States and/or other countries.

Other company, product, and service names may be trademarksor service marks of others.

Copyright © 2004, 2005 ABAQUS, Inc. All Rights Reserved.

MAR_INS_501

IInndduussttrryy EEvveennttss

Pacific Design and ManufacturingJanuary 10-12, 2005Anaheim, CAwww.devicelink.com/expo/pac05

EEConsult SeminarFebruary 16, 2005Gent, Belgium

Tire Technology ExpoFebruary 22-24, 2005Koln, Germanywww.tiretechnology-expo.com

Virtuelle Produktentwicklung in der FahrzeugtechnikMarch 9-10, 2005Mürzzuschlag, Austriawww.payerconsulting.com/events

National Design Engineering ShowMarch 7-10, 2005Chicago, ILwww.designengineeringshow.com

COE 2005 Annual Conferenceand TechnifairMarch 20-23, 2005Phoenix, AZwww.coe.org/events/05conference

MICADApril 5-7, 2005Paris, Francewww.birp.com/micad

Hannover Messe 2005April 11-15, 2005Hannover, Germanywww.hannover.messe.de

Eurosime 2005April 17-20, 2005Berlin, Germanywww.eurosime.com

Nafems WiesbadenApril 25-28, 2005Wiesbaden, Germanywww.nafems.de

Solid Modeling 2005April 27-28, 2005Birmingham, U.K.www.edaexhibitions.com/SM

Materials EngineeringMay 11-12, 2005Eindhoven, The Netherlandswww.materialsengineering.nl

SAE Noise and Vibration CongressMay 16-19, 2005Traverse City, MIwww.sae.org/events/nvc

AVL AST User MeetingJune 13-14, 2005Graz, Austriawww.avl.com/ast2005

ECCMR 2005-Fourth European Conference on ConstitutiveModels for RubberJune 27-29, 2005Stockholm, Swedenwww.abedia.com/eccmr

European Automotive CFD Conference (Fluent)June 29-30, 2005Frankfurt, Germanywww.engineeringtalk.com

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