SBIR-STTR Award

Because of their macromolecular structure, elastomers exhibit unique behavior and require special-purpose modeling and simulation methods. Endurica has developed a patented system for the simulation of fatigue life in elastomeric materials. The fatigue life is the number of cycles that a material will tolerate before developing a crack of specified size. The analysis system embodies 10 man-years of development, and its author has received numerous awards for the work. We propose to address the subject SBIR Phase I feasibility study by applying our simulation system to a series of tasks selected to demonstrate its underlying principles and operability. The tasks will be developed around the following main themes: 1) material model definition, 2) analysis of the multiaxial, variable amplitude duty cycle occurring at a single material point, and 3) simulation of crack nucleation in a rubber component simulated via finite elements. The proposal includes the option to further demonstrate workflow feasibility by experimentally characterizing two materials following our analysis schema.

Keywords:
Fatigue Life, Rubber, Strain, Crack, Fea, Multiaxial, Variable Amplitude, Duty Cycle

Engineering and qualifying a rubber component for dynamic applications is often time-consuming and expensive due to the need to control fatigue failure. Endurica’s Phase I project demonstrated feasibility of using numerical simulation of rubber’s failure process to compute effects of material properties, component geometry, and applied duty cycle. Through simulation, Endurica provides means to evaluate fatigue performance before costs of component testing start to accrue. Funding Endurica’s Phase II proposal will enable the implementation, testing, and productization of a wide range of capabilities useful for simulating fatigue failure of rubber components. The final deliverable will include the ability to analyze multiaxial, variable amplitude duty cycles, to consider the unique material characteristics of rubber (inclusive of temperature effects), and to account for self-heating of the rubber under the action of dynamic loading. The code will include a user-oriented, menu-driven interface. Using the new tool, a case study will be made of a tank track backer pad. The backer pad material will be fully characterized, and finite element analysis of its mechanical and thermal behavior will be run to determine strain history and operating temperature. Fatigue life predictions of the backer pad will be compared with experimental observations.

Keywords:
Fatigue Life Prediction, Elastomer Improvement Program, Tank Track Systems, Finite Element Analysis, Backer Pad, Multiaxial, Variable Amplitude, Product Development