INTEGRATED COMPUTATIONAL MATERIAL ENGINEERING FOR ...
Verification of Integrated Computational Material Engineering for Virtual Life Management® of Medical Devices S. Kulkarni*, R. Tryon#, K. Merdan*, G. Krishnan# ASTM Third Symposium on Fatigue and Fracture Metallic Medical Materials and Devices
* Boston Scientific, # Vextec Corporation
November 14, 2012 Hyatt Regency Atlanta, GA
Copyright © 2012 by Boston Scientific Corporation or its affiliates. All rights reserved.
Talk Outline
• • • • •
ICME Technology Virtual Twin® Application to MP35N Lead Simulations Results Perspectives and Summary
Copyright © 2012 by Boston Scientific Corporation or its affiliates. All rights reserved.
Integrated Computational Material Science
• Virtual Twin – Computer model that represent all structural aspects of a component (or system)
Integrated Computational Materials Engineering: A Transformational Discipline for Improved Competitiveness and National Security (http://www.nap.edu/catalog/12199.html) Copyright © 2012 by Boston Scientific Corporation or its affiliates. All rights reserved.
Virtual Twin Used to Determine Costs
• Computation methods are available to determine blue line (loads) • Red line (capacity) is traditionally determined with lots and lots of testing • ICME determines red line using computational methods and less testing
Copyright © 2012 by Boston Scientific Corporation or its affiliates. All rights reserved.
ICME Extends FEA to Durability Analysis Standard Industry Analysis
Design & Stress
With ICME
Life & Where & Why
Copyright © 2012 by Boston Scientific Corporation or its affiliates. All rights reserved.
Material Structures Models 1. Grain energy input into well known and accepted material science damage equations
2. Grain lives statistically combined into element life; then component life
3. Actual “mission” simulation by sequencing FEA models and repeating above steps Mission Cycle 1 2 3 4 5
Component Life Usage
Copyright © 2012 by Boston Scientific Corporation or its affiliates. All rights reserved.
risk area
Knowledge & Rules Fatigue Analysis
• Crack nucleation
• Small crack growth
• Long crack growth Copyright © 2012 by Boston Scientific Corporation or its affiliates. All rights reserved.
MP35N Lead VT Objective Demonstrate VLM Technology • Ability to predict product durability under varying conditions • Provide understanding of technology and the benefits of VT Simulators
Specifically….. • Simulate fatigue buckling test under 2 load conditions • Conduct Sensitivity Studies around principal durability drivers • Provide opportunity to compare predicted trends against known trends
Copyright © 2012 by Boston Scientific Corporation or its affiliates. All rights reserved.
Simulator Set-up for MP35N Wire Rotating Bend Fatigue Test
Grain Size
Residual Stress
Particle Size J. E. Schaffer: Ph.D. Thesis, Purdue, 2007 Copyright © 2012 by Boston Scientific Corporation or its affiliates. All rights reserved.
Fatigue Mechanisms Nucleation
Small Crack Growth
Near-initiation, cracked TiN particle
Crack front arrest at microstructural features.
Chevron crack-initiating feature
Striation spacing at crack front J. E. Schaffer: Ph.D. Thesis, Purdue, 2007
Copyright © 2012 by Boston Scientific Corporation or its affiliates. All rights reserved.
Perform Simulations on Wire Test
Copyright © 2012 by Boston Scientific Corporation or its affiliates. All rights reserved.
Fatigue Test Design Set-up for MP35N Leads
Cond1: A”+/-a” Cond2: B”+/-b”
Condition 1: A” Von Mises Stress; Max Stress=XX ksi
• • • •
Simulation of two test conditions – Displacements A” and B” Cycling between maximum displacement and 0 displacement Cycling to 1E10 cycles and Runout (suspension) if no failure Measured difference in maximum Von-Mises stress between Conditions 1 and 2 Copyright © 2012 by Boston Scientific Corporation or its affiliates. All rights reserved.
Condition 2: B” Von Mises Stress; Max Stress=YY ksi
MP35N Coil Simulation Set-up • • • •
Define geometry and stress with FEA Define microstructure with metallography Run Simulation Calibrate to residual stress profile with experimental data
Copyright © 2012 by Boston Scientific Corporation or its affiliates. All rights reserved.
Sensitivity Study Virtual Design of Experiments – Applied displacement – Residual stress profile – Inclusion size distribution
•
Top durability drivers
Copyright © 2012 by Boston Scientific Corporation or its affiliates. All rights reserved.
…
– Residual Stress – 10% improvement yields 60% improvement in mean total life – Inclusion Size – 50% smaller inclusion size yields 25% improvement in mean total life – Inclusion Density- 50% lower inclusion density; No significant impact – Trade-off threshold exists between residual stress and inclusion size
Global Perspective and Summary •
Able to Characterize MP35N lead design • Material Microstructure (grain size, inclusion size and density) • Residual Stress
•
Developed Insights • Concept or design alternatives • Material substitution or vendor management
•
Potential application of VLM • Sensitivity analysis • Design trade studies • Supplier controls • Design optimization • Next Steps – new materials and new designs
Copyright © 2012 by Boston Scientific Corporation or its affiliates. All rights reserved.
* Boston Scientific, # Vextec Corporation
November 14, 2012 Hyatt Regency Atlanta, GA
Copyright © 2012 by Boston Scientific Corporation or its affiliates. All rights reserved.
Talk Outline
• • • • •
ICME Technology Virtual Twin® Application to MP35N Lead Simulations Results Perspectives and Summary
Copyright © 2012 by Boston Scientific Corporation or its affiliates. All rights reserved.
Integrated Computational Material Science
• Virtual Twin – Computer model that represent all structural aspects of a component (or system)
Integrated Computational Materials Engineering: A Transformational Discipline for Improved Competitiveness and National Security (http://www.nap.edu/catalog/12199.html) Copyright © 2012 by Boston Scientific Corporation or its affiliates. All rights reserved.
Virtual Twin Used to Determine Costs
• Computation methods are available to determine blue line (loads) • Red line (capacity) is traditionally determined with lots and lots of testing • ICME determines red line using computational methods and less testing
Copyright © 2012 by Boston Scientific Corporation or its affiliates. All rights reserved.
ICME Extends FEA to Durability Analysis Standard Industry Analysis
Design & Stress
With ICME
Life & Where & Why
Copyright © 2012 by Boston Scientific Corporation or its affiliates. All rights reserved.
Material Structures Models 1. Grain energy input into well known and accepted material science damage equations
2. Grain lives statistically combined into element life; then component life
3. Actual “mission” simulation by sequencing FEA models and repeating above steps Mission Cycle 1 2 3 4 5
Component Life Usage
Copyright © 2012 by Boston Scientific Corporation or its affiliates. All rights reserved.
risk area
Knowledge & Rules Fatigue Analysis
• Crack nucleation
• Small crack growth
• Long crack growth Copyright © 2012 by Boston Scientific Corporation or its affiliates. All rights reserved.
MP35N Lead VT Objective Demonstrate VLM Technology • Ability to predict product durability under varying conditions • Provide understanding of technology and the benefits of VT Simulators
Specifically….. • Simulate fatigue buckling test under 2 load conditions • Conduct Sensitivity Studies around principal durability drivers • Provide opportunity to compare predicted trends against known trends
Copyright © 2012 by Boston Scientific Corporation or its affiliates. All rights reserved.
Simulator Set-up for MP35N Wire Rotating Bend Fatigue Test
Grain Size
Residual Stress
Particle Size J. E. Schaffer: Ph.D. Thesis, Purdue, 2007 Copyright © 2012 by Boston Scientific Corporation or its affiliates. All rights reserved.
Fatigue Mechanisms Nucleation
Small Crack Growth
Near-initiation, cracked TiN particle
Crack front arrest at microstructural features.
Chevron crack-initiating feature
Striation spacing at crack front J. E. Schaffer: Ph.D. Thesis, Purdue, 2007
Copyright © 2012 by Boston Scientific Corporation or its affiliates. All rights reserved.
Perform Simulations on Wire Test
Copyright © 2012 by Boston Scientific Corporation or its affiliates. All rights reserved.
Fatigue Test Design Set-up for MP35N Leads
Cond1: A”+/-a” Cond2: B”+/-b”
Condition 1: A” Von Mises Stress; Max Stress=XX ksi
• • • •
Simulation of two test conditions – Displacements A” and B” Cycling between maximum displacement and 0 displacement Cycling to 1E10 cycles and Runout (suspension) if no failure Measured difference in maximum Von-Mises stress between Conditions 1 and 2 Copyright © 2012 by Boston Scientific Corporation or its affiliates. All rights reserved.
Condition 2: B” Von Mises Stress; Max Stress=YY ksi
MP35N Coil Simulation Set-up • • • •
Define geometry and stress with FEA Define microstructure with metallography Run Simulation Calibrate to residual stress profile with experimental data
Copyright © 2012 by Boston Scientific Corporation or its affiliates. All rights reserved.
Sensitivity Study Virtual Design of Experiments – Applied displacement – Residual stress profile – Inclusion size distribution
•
Top durability drivers
Copyright © 2012 by Boston Scientific Corporation or its affiliates. All rights reserved.
…
– Residual Stress – 10% improvement yields 60% improvement in mean total life – Inclusion Size – 50% smaller inclusion size yields 25% improvement in mean total life – Inclusion Density- 50% lower inclusion density; No significant impact – Trade-off threshold exists between residual stress and inclusion size
Global Perspective and Summary •
Able to Characterize MP35N lead design • Material Microstructure (grain size, inclusion size and density) • Residual Stress
•
Developed Insights • Concept or design alternatives • Material substitution or vendor management
•
Potential application of VLM • Sensitivity analysis • Design trade studies • Supplier controls • Design optimization • Next Steps – new materials and new designs
Copyright © 2012 by Boston Scientific Corporation or its affiliates. All rights reserved.
