structural health monitoring : role of modelling and...
TRANSCRIPT
Structural Health Monitoring : Role of Modelling and Simulation
Fumio KOJIMA Organization of Advanced Science and Technology Graduate School of Sytem Informatics, Kobe University, Kobe, Japan (Phone/Fax +81-78-803-6493; E-mail: [email protected])
システムモデル論(第3回) H23.10.19 モデリングI
Scenario of the talk
1. Background and Aim of Research 2. Structural Health Monitoring using Inverse Analysis 3. Current and New Direction for SHM
Research Project
Projects of System Group: Inverse Problems in Nondestructive Evaluation
Condition Monitoring
New NDE for Nanoscale Defects
Cooperative Organization
CRSC, North Carolina Sate University, NC USA National Institute for Applied Mechanics, HCMC, Vietnam
Inverse Problems in Nondestructive Evaluation NASA
AIST
JAXA
Cyber-Infrastructure of Remote NDE System: Electrical Potential Method:
Scenario of the talk
1. Background and Aim of Research 2. Structural Health Monitoring using Inverse Analysis 3. Current and New Direction for SHM
Remark: Structural health monitoring is a promising technology in keeping safety of large scale complex systems, such as nuclear power plants, airplanes, etc. It involves the broad concept of assessing ongoing and in-service performance of structures using variety of measurements. Those elements include sensors in structures, data acquisition, data management, data interpretation, diagnosis, etc.
First Project
NASA Langley Research Center, Hampton Virginia
Nondestructive Evaluation Science Branch (1987~)
January 28, 1986
Abridgement
IX MAINTENANCE SAFEGUARDS
Installation, test, and maintenance procedures must be especially rigorous for Space Shuttle items designated Criticality 1. NASA should establish a system of analyzing and reporting performance trends of such items. Maintenance procedures for such items should be specified in the Critical Items List, especially for those such as the liquid-fueled main engines, which require unstinting maintenance and overhaul. With regard to the Orbiters, NASA should: Develop and execute a comprehensive maintenance inspection plan. Perform periodic structural inspections when scheduled and not permit them to be waived. Restore and support the maintenance and spare parts programs, and stop the practice of removing parts from one Orbiter to supply another.
Measurement Equipment at NASA Langley Research Center
(1988, ABC World News)
Shape Reconstruction using Thermal Data
Heat Lamp Heat Lamp
Infrared Camera Input :Heat-up at Surface
Output:Surface Measurement
Inspection Model
(Inverse Problems, 1991)
Why do we need to estimate material defect?
It is important to evaluate material system used in passenger flight, bridge, nuclear power plant for their safety.
Health monitoring techniques are available using various kinds nondestructive test but it is not enough information from current technologies.
Computational techniques play key role in maintenance technologies
Nondestructive Evaluation Science Measurements
+ High performance Computing
Type of Nuclear Power Plants There are two separate coolant loops in PWRs. Heating the water in the primary coolant loop by thermal conduction through the fuel cladding and it is pumped into the steam generator, where heat is transferred to the lower pressure secondary coolant.
BWR has only one coolant loop. Heat is produced by nuclear fission in the reactor core and the producing steam is directly used to drive a turbine. In BWR, the core shroud is a large stainless steel cylinder of circumferentially welded plates surrounding the reactor fuel core.
The fast breeder reactor (FBR) is the next generation of NPPs and a fast neutron reactor designed to breed fuel by producing more fissile material than it consumes.
JSFR Monjyu
Conventional Inspection Technologies (ECT)
In PWR, the steam generator tubes constitute one of the primary barriers between the radioactive and non-radioactive sides of the plant. Therefore, in-service inspections (ISI) of the steam generator tubes are essential in keeping safety of operations.
Crack Reconstruction using Inverse Analysis
Eddy Current Signal Shape Reconstruction
International Benchmark Problem (1999-2000)
Primary coolant loop
Secondary coolant
Conventional Inspection Technology (UT)
Scenario of the talk
1. About Our Laboratory 2. Background and Aim of Research 3. Structural Health Monitoring using Inverse Analysis 4. Current and New Direction for SHM
Remark: Structural health monitoring is a promising technology in keeping safety of large scale complex systems, such as nuclear power plants, airplanes, etc. It involves the broad concept of assessing ongoing and in-service performance of structures using variety of measurements. Those elements include sensors in structures, data acquisition, data management, data interpretation, diagnosis, etc.
Our Strategies
Mathematical modelling of NDT and defect profiles Forward analysis for constructing virtual inspection images Inverse analysis for model-based NDT
A direct problem is to design a real NDT system mathematically using the input and output relation with the appropriate admissible class of material flaws, while an inverse problem is to construct a method for recovering and/or visualizing material flaw information under the mathematical formulation of the direct problem.
Three Procedures:
SCC Monitoring In BWR, the core shroud is a large stainless steel cylinder of circumferentially welded plates surrounding the reactor fuel core. The shroud provides for the core geometry of the fuel bundles. Extensive cracking of circumferential welds on the core shroud has been discovered in an increasing number of Japanese BWRs plants since 2002.
Network Tomography
Grand test (Natioanl Project 2004-2006)
Network tomography implements the hybrid use of real-virtual system in NDT environments
Ground Test
Inspection Module
Computational Module
Communication Interface Module
Inverse Analysis
Computational Agent
Evaluator
Mobile Interface
Data Sending
Underwater Manipulator
Sensor Plate Curved Corner
Measurement Server
Probe
ECT Sensor
Operator
National Project (Hitachi Ltd., Tohoku Univ., Polytech. Univ. and Kobe Univ., 2004-2006)
Mathematical Modeling of NDT (Procedure I)
CrackTransmitterRecieverEddy CurrentConductor
Induced voltage
Electromagnetic Field in Sample
Simulator (FEM)
FEM matrix BEM matrix
crack
Fast Solver using Domain Decomposition Method
Finite Elements
Crack Elements
Crack model
Conductivity vector
Modeling of SCC
Surface of natural crack Finite element cracking model
Stress corrosion cracking is quite complicated structures for sizing. In our approach , complexity of real cracks are approximated by a set of rectangular solids. Each solid is characterized by its own properties, such as length, width, depth, and physical parameters.
Modeling of Defect Profiles (SCC)
Forward Analysis for ECT (Procedure II)
Measurement
Frequency Control Scanning Strategy
ECT Simulator
Defect Parameter Conductivities Position Number of Defects
Virtual Image
Inverse Analysis (Procedure III)
ECT Measurements
Crack shape ?
Crack Parameter
Crack Model Evaluation Update crack
parameter
Virtual Image
Forward Analysis
Inverse Analysis
+
‐
Measurement Image Crack Parameter :
Test Example (SUS sample with SCC)
-0.2 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 0 0.01 0.02 0.03 0.04X1 (m) 0 0.01 0.02 0.03 0.04 0.05X2 (m)
True Shape Estimate Shape
In this lecture, it was shown that modeling and simulation of NDT is indispensable problem-solving methodology for implementing high performance monitoring of NPPs.
Electromagnetic inverse methodologies for sizing stress corrosion crack were considered for boiled water reactor (BWR) plants. It is very crucial to characterize target cracking of SUS304 and SUS316L materials used in BWR plants since those involve various kind of complexities, such as orientation, multiple deep-lying branching, partially conducting, etc.
The model based health monitoring system was outlined for sizing natural crack in three dimensions. The feasibility and validity of our inverse algorithm using laboratory data were demonstrated.
Scenario of the talk
1. About Our Laboratory 2. Background and Aim of Research 3. Structural Health Monitoring using Inverse Analysis 4. Current and New Direction for SHM
Remark: Structural health monitoring is a promising technology in keeping safety of large scale complex systems, such as nuclear power plants, airplanes, etc. It involves the broad concept of assessing ongoing and in-service performance of structures using variety of measurements. Those elements include sensors in structures, data acquisition, data management, data interpretation, diagnosis, etc.
Critical Issues From Time Based Maintenance (TBM) to Condition Based Maintenance (CBM),… What kinds of philosophy (or concept) of NDT is necessary?
Condition monitoring plays an essential role!
Modeling methodologies of material failure progress
Research Direction
Data assimilation
Predictive model
Feasible management for sensor networks in aircraft
Lifetime estimate of aircraft components using stochastic inverse analysis
New Methodology for Health Monitoring based on s Stochastic Simulations