introduction of static analysis using sw 2010

Introduction of Static Analysis Using Solidwork 2010

Ewantalib, 2013

Training Module 1



Ewantalib, 2013

1-1 Introduction of Static Analysis 1 – 3 1-2 Create New Study 1 – 4 1-3 Material Properties 1 – 6 1-4 Boundary Conditions 1 – 7 1-5 Loading Conditions 1 – 9 1-6 Meshing Process 1 – 11 1-7 Result 1 – 13

Contents


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In this module, we will use the SolidWorks Simulation finite element analysis (FEA) program to

analyse the response of a component to an applied load. Finite element analysis is a powerful tool that

allows engineers to quickly analyse and refine a design. It can be applied to problems involving vibration,

heat transfer, fluid flow, and many other areas. The most common use of FEA is in structural analysis,

and this chapter will be limited to that use.

There has been much discussion during the past decade over who should be using FEA software.

As the software has become easier to use, the potential for misuse has risen. An inexperienced user can

quickly obtain results, but the interpretation of the results requires knowledge of the applicable

engineering theories. In this tutorial, we will point out where choices and assumptions are made that

could affect the accuracy of the results.

Static (or Stress) studies capable to determine calculate displacements, reaction forces, strains,

stresses, failure criterion, factor of safety, and error estimates. Available loading conditions include

point, line, surface, acceleration (volume) and thermal loads are available. Elastic orthotropic materials

are available.

1-1 Introduction of Static Analysis


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Many of the tools in the Simulation Group of the Command Manager have an “Advisor” feature.

For example, if you select the Study Advisor Tool, then the software leads you through several questions

to help you choose the best analysis type. We will be skipping the Advisors and selecting analysis option

directly from the pull‐down menus below each Advisor Tool.

In a static analysis, we assume that that loads are applied slowly. If loads are applied almost

instantaneously, then dynamic effects need to be considered. A linear static analysis assumes that the

response of the structure is linear.

PROCEDURE

1. Open the cad data, “Crane Hook”.

Figure 1: Hook

2. Click “Office Products” bar and choose “Solidwork Simulation” in “SolidWorks Office” list. Then,

“Simulation” bar will appear.

1-2 Create New Study


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Figure 2: SolidWork Office

3. Click “New Study” in “Study Advisor” list and choose “Static” for type of analysis rename it as

“Static Analysis on Crane Hook”. Then, click symbol.

4. The design trees for modelling and analysis are shown at left side. Command for analysis

operation can be found on upper side.

Figure 3: Create new study


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One of the most important inputs to the model is the elastic modulus E of the material. The

elastic modulus defines the stiffness (resistance to deflection) of the material. Its value is determined

from material tests. A material with a high value of E will deflect less than one with a lower value of E.

PROCEDURE

1. Click “Apply Material” to assign type of material used for the part and material library will pop

out. Choose Alloy Steel in Steel folder and click “Apply”. Then, close it.

1-3 Material Properties

Figure 4: Command bar

Command bar Design Tree


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Figure 5: Material selection

The symbol will appear on thumbnail shown that material had been applied.

When a component is isolated for analysis, the way in which that component is attached to

another must be simulated with boundary conditions. In this case, we have chosen a fixed restraint,

which means that every point on the fix face of the hook is prevented from moving in any direction.

While this seems to be a reasonable assumption, it may not be entirely accurate. If pin are used and

attach the hook to chain etc., then the pin is assume may stretch enough and have no issues in its

straightness. Hence, this analysis can focus on hook only which is the main problem. It is not necessary

to include all assembly to be analyse because it will wasting time. Try to simplify it. The choice of proper

boundary conditions to simulate actual constraints is often one of the most important decisions to be

made for an analysis.

1-4 Boundary Conditions

Figure 6: Applied material sign


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PROCEDURES

1. Define the boundary condition or apply fixtures. Click the small arrow below “Fixtures Advisor”

and choose “Fixed Geometry”.

Figure 7: Chain and hook assembly

Chain

Connector

Pin

Hook


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Figure 8: Boundary condition

Choose the fix surfaces as picture below. Then, click the symbol.

Figure 9: Fixture

Face 2 Face 1


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The simplest definition of stress is that stress is equal to force per unit area. Therefore, the units of

stress are newtons per square meter (Pascals). However, stress is not a single value. There are normal

stresses in all three directions. Normal stresses cause a material to stretch or contract. There are also

shear stresses in all three planes. Shear stresses cause a material to warp or distort. These six stress

components are often combined to find principal stresses.

Strength is defined as the stress at which a material will fail. Therefore, for a simple state of stress,

such as a wire being stretched in one direction, we can simply compare the stress to the strength to

determine if the wire will break.

PROCEDURES

1. Define the loading condition or external loading. Click the small arrow under “External Loads”

and choose “Force”.

Figure 10: External load

1-5 Loading Conditions


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Choose the surface as picture. Tick the “selected direction” and choose top plane as the normal

direction of the force. Click the “normal to plane” thumbnail and insert 5000N. Click the reverse

direction if necessary so that the force going downward. Then, click the symbol.

Figure 11: Applied load

Load exerted


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A finer mesh, with more elements, will generally produce more accurate results at the expense of

longer processing time. For simple parts and a relatively fast computer, the longer processing time is not

significant. However, for complex analyses (such as non‐linear and time‐dependent analyses), mesh size

can significantly impact processing time. How many elements are needed for accuracy? Sometimes it is

necessary to experiment with different meshes until the results converge to a solution. In other cases,

the mesh can be refined to create more elements in a local area where stresses are greatest.

PROCEDURES

1. To create mesh, click small arrow under “Run” and click “Create Mesh”.

Figure 12: Create mesh

1-6 Meshing Process


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In the Mesh option at the left, drag the cursor to the finest density and in advance setting

tick the “Draft Quality Mesh”. Then, click the symbol and the Mesh Process will be

shown.

Figure 13: Applied mesh

Note!

Mesh Density ↑

Accuracy ↑

Processing time ↓


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For a more complex state of stress, we must choose a failure theory in order to predict whether

or not the part will fail. One of the most widely used in the von‐Mises or maximum‐distortion‐

energy theory. In our analysis, the software computed the von‐Mises equivalent stress, which can

be compared to the material’s yield strength to predict yielding of the part.

PROCEDURES

1. After the meshing process complete, click “Run”.

2. Then, choose the related results outcome. In static analysis, basic results used are Stress,

Factor of Safety, and Displacement. Click small arrow below “Results Advisor” and choose

“Stress” and click “Stress”.

1-7 Result

Figure 14: Meshing process

Figure 15: Results selection


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At the option for Stress Plot, choose “VON: von Mises Stress” and unit “N/m2. Then, click the

symbol and stress result will be shown.

Repeat the step for the FOS result.

The factor of safety is chosen to account for all of the many uncertainties associated

with the analysis (loading, material properties, environmental degradation of material, etc.)

In some industries, factors of safety of 10 or more are common. In aerospace applications,

Figure 16: von Mises Stress

Figure 17: Factor of safety


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where weight is critical, factors of safety of less than two are typical. When a lower factor of

safety is used, extensive material testing and analysis are used to reduce uncertainty as

much as is practical.

Repeat the step for the Displacement result.

The maximum deflection is shown as about 0.286mm. This value is the resultant of the

deflection in all three directions. Note that the deflections are too obvious in the display of the

deflected shape but the deflections of most structural parts are usually very small, scaling their

values to produce the deflected shape is a common practice. The deflected shape gives the engineer

insight into the behaviour of the structure and results outcome.

3. The part can be identified either fail or save by comparing the value for von Misses stress

and yield strength /young modulus of the material property. The part is considered save if

maximum value of von Mises stress did not exceed the yield strength. FOS also can show the

capability of the part. The part is considered save if minimum value of FOS over than 1, the

bigger value is better.

Figure 18: Deformation/ deflection


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4. For this case the result showed that maximum von mises stress is 379.152MPa which is

smaller than its yield strength, 620.4MPa. Hence, this part passed the test.

5. Maximum stress that can be support by hook can be determined by apply this formula:

Maximum force, Fmax =

Hence;

Maximum force, Fmax =

=8200N

m = current min FOS

F= current load applied

FOS = >1.0 (save condition)

introduction of static analysis using sw 2010

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