Multiphysics Foundations for Material State Change Prognosis in Material Systems UNIVERSITY OF SOUTH CAROLINA “Forward Projected State Awareness” Form relates to function + Substance relates to performance  What something is determines what it does - and what it will do “The material is the sensor”

Strength Concepts for Large Nonlinear Deformations of Woven Composites at Different Strain Rates Acknowledgements: “Foundations for Mechanical Prognosis of Nano-Structured Membranes,” AFOSR, Victor Giurgiutiu Constitutive Modeling for Mechanical Response of Ionomer- Based Nano-Phased Composite Laminates,” Sponsor: NSF Strength Concepts for Large Nonlinear Deformations of Woven Composites at Different Strain Rates, ONR / GD Electric Boat UNIVERSITY OF SOUTH CAROLINA

Material Systems  Distributed Properties (e.g. ‘damage’) UNIVERSITY OF SOUTH CAROLINA “Damage Tolerance and Durability of Material Systems” Kenneth Reifsnider & Scott Case John Wiley, 2003 Ken Reifsnider

Distributed Damage  Reliability ~ conditional probability UNIVERSITY OF SOUTH CAROLINA Ken Reifsnider Risk analysis specifies an exponential relibility Then “collecting” damage: a = 4 a = 12

Distributed Damage  Nonlinear stress strain behavior UNIVERSITY OF SOUTH CAROLINA Elastic: Plastic: h(  ): Elastic-plastic analysis:  Single master curve Large deformation ~ distributed damage: Liqun Xing Ken Reifsnider 15 o 30 o 45 o 60 o 90 o 0 o

Constitutive Models Related literature: 1. Weeks C.A. and Sun C.T.; Design and Characterization of Multi-core Composite Laminates, 38 th International SAMPE Symposium, May 10-13, pp , Sun, C.T. and Potti S.V., A simple model to predict residual velocities of thick composite laminates subjected to high velocity impact, Int. J. Impact Engg, V. 18, No. 3 pp , Sun C.T. and Chen, J.L., Composite Materials, 23, , Tamuzs, V.m, Dzelzitis, K. and Reifsnider, K.L., Applied Composite Materials, Vol.11 No.5, , Tamuzs, V.m, Dzelzitis, K. and Reifsnider, K.L., Applied Composite Materials, Vol.11 No.5, , Ogihara, S. and Reifsnider, K.L., Applied Composite Materials, Vol.9, , 2002

 Constitutive equations representing that progressive damage were constructed, and generalized for ABAQUS :  captures strain-rate dependence  only one time dependent parameter

Finite Element Verification & Validation: Failure surfaces Contour of failure index

UNIVERSITY OF SOUTH CAROLINA Liqun Xing Ken Reifsnider Micro-cracking  Strain to break Models of specific local material state changes can be used to correctly estimate limits of behavior  How can we relate the other specific events that control the state of the material to real-time measurements to create state awareness that specifies mechanical state variables like stiffness, strength, and life?

 Mass Balance  Charge Transfer Balance  Species Diffusion  Momentum  Energy Balance  Stress-Strain Temperature dependent properties: conductivity, exchange current density, species diffusion, polarizations, thermal stress, capacitance… Results: Material system response coupled to material state, in real time? Heat Transfer: Sources- overpotentials, entropy changes Sink- heat conduction, convection and radiation Governing Equations Physics Multiphysics representation of response in terms of material state: (the material is the sensor) Ken Reifsnider Material state = set of all physical variables needed to define system performance

Conductivity – by using a cyclic excitation voltage in our simulation, we were able to predict the impedance behavior of an actual microstructure, which compares very well with the observed results for the bulk material of that type  microstructure becomes a multiphysics indicator of material state UNIVERSITY OF SOUTH CAROLINA Ken Reifsnider Surface 1, BC1 Surface 2, BC2 Electrochemical Impedance Spectroscopy provides data that relate to microstructure 

AC Simulation Impedance spectra calculated by finite element method and corresponding measured result for as-received and as-aged 10ScSZ1550. Microstructure changes correctly predict EIS results  a measure of local conduction paths, geometry, and micro-constituent properties Ken Reifsnider, Gang Ju

Impedance / conductivity –  requires a path  reflects material properties, properties, geometry, interfaces at the local level in a fundamental way  dynamic measurements are sensitive to transport, chemical or electrochemical activity, microstructural integrity, interfaces, …  distributed sensor / detector technology is out there  we can model the physics (good foundation in the literature) UNIVERSITY OF SOUTH CAROLINA Ken Reifsnider

References: Zhu Dongming and Miller Robert A 2000 MRS Bulletin 25 n State changes : porosity / tortuosity Ohmic resistance interface phase formation impurity migration microcracking / delamination conductivity (T, i) stiffness strength …. Rate equations : Multiphysics analysis : balance equations constitutive equations boundary conditions extensive variables as functions of time Predicted specific power density as function of history of operation, design, manufacturing : Mechanical performance, failure prediction : Durability – a general multiphysics-based approach: Foundations for Durability of Fuel Cells and Fuel Cell Systems Ken Reifsnider

Mechanical condition can be measured by EIS methods: UNIVERSITY OF SOUTH CAROLINA Ken Reifsnider Liqun Xing, Paul Fazzino Fractured Glass Fiber Composite: EIS data:

Mechanical degradation can be measured by EIS methods: UNIVERSITY OF SOUTH CAROLINA Ken Reifsnider Liqun Xing, Paul Fazzino

UNIVERSITY OF SOUTH CAROLINA Ken Reifsnider Measurements: Impedance spectroscopy Interpretation: Multiphysics Material mechanical state: Composite mechanics Performance: Remaining stiffness, strength and life as a function of expected operation environment Science Advance  multiphysics  material state Technical Advance  material state  mechanical performance methodologies

ELECTRONIC STD WORK INTEGRATED INTO ELECTRONIC PROCESS MAPS & ASSOCIATED WITH WORK INSTRUCTIONS ELECTRONIC IPD A B D E F C G IPT 1 IPT 2 IPT 3 WORK FLOW MANAGEMENT COLLABORATIVE ENGINEERING SECURE B2B DESIGN AUTOMATION A B D E F C G SYSTEM OPTIMIZER IPT 1&2 IPT 3 AUTOMATE ITERATION SATISFY CRITERIA GRID COMPUTING LIBRARY OF “WRAPPED” TOOLS ABCBCG ACCURATE VALIDATED CERTIFIED CONTROLLED Proprietary tools INTEGRATION FRAMEWORK CG B DF H INTEGRATE THIRD PARTY & LEGACY TOOLS INDUSTRY ACCEPTED COMMERCIAL Commercial of the shelf (COTS) Available  FIPER, CO, ModelCenter Internal PW Standard Work & IPD Process Center for eDesign, Airforce ACD&D, CAD PDMs COTS: iSIGHT 45 What do we do with such foundations?

46 We must provide representations and models of material systems that can be used to design and manufacture engineering structures. What do we do with such foundations?

UNIVERSITY OF SOUTH CAROLINA Material models  Nonlinear stress strain behavior Elastic- viscoplastic analysis: Large deformation, material models can represent such behavior, but not specific events or types of damage  Liqun Xing