Modeling and fracture prediction in rubber composites
Abstract
A finite element method is developed to predict failure in rubber composites (such as cord-rubber, silicone-elastomer, etc.) for design applications in aerospace and automotive industries. The numerical predictions are also verified through experimentation. The critical tearing energy approach is used as a fracture criterion to predict failure within the rubber material. The tearing energy for arbitrarily cracked geometries is calculated by the virtual crack extension method using 8-node isoparametric finite elements, which are formulated based on a variation of geometric mapping. To illustrate the accuracy and value of the present formulation, examples of a single edge crack specimen and a pure shear crack specimen which are commonly used in fatigue and fracture studies of rubber were studied. The results obtained are compared with alternative solutions and experimental data available and good agreement was found. For the experimental verification, the mechanical and fracture properties of SBR (Stryrene Butadiene Rubber) material that undergoes large elastic deformations are determined from experimental tests on simple rubber specimens. To demonstrate the critical tearing energy approach and the present formulations, the predicted critical loads or critical tearing energies for crack growth initiation and final fracture, as well as the crack growth initiation direction for arbitrarily shaped mixed-mode rubber specimens, are compared to the experimental data with good agreement. A finite element model for single ply cord-rubber composites is developed to predict the nonlinear behavior and critical loads for crack growth. To illustrate the nonlinear behavior, the finite element results are compared to the experimental data on tensile tests. Using this finite element model and the critical tearing energy as fracture criterion, critical loads for crack growth of various cracked rubber composite specimens are predicted and compared to the experimental data with good agreement.
Degree
Ph.D.
Advisors
Yang, Purdue University.
Subject Area
Aerospace materials
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