Degree Candidacy: Master of Science in Mechanical Engineering
Date: Monday, May 5, 2014
Time: 9:00 AM
Location: 215 EIB
Advisor: Dr. Georges Fadel
Committee Members: Dr. Nicole Coutris and Dr. Gang Li
Title: Identifying target properties for the design of meta-material tank track pads
On track vehicle systems, track pads are designed to provide traction and support the weight of the vehicle, they have limited service life due to common failure by blowout. According to the literature, blowout is a failure mode caused by overheating due to hysteresis in elastomeric materials during high speed operations. Elastomers are used primarily for their high compliance, which is essential to protect the suspension components and maintain structural integrity of the track pad. The objective of the work is to explore the use of linear elastic meta-materials with optimized topology to replace elastomers and reduce or eliminate the effect of hysteretic loss.
This work presents a methodology to design an alternate meta-material that can provide some of the desired elastic properties of the track pads. To determine the requirements for linear elastic meta-materials, dynamic analyses of a rollover event were conducted. From these analyses the complex dependence of the strain history on different strain components is understood. Due to the non-linearity of elastomers, tangent stiffness matrices are required to update the stress state in consequence of a new strain increment. The elasticity tensors (tangent operators) determined at a set of strain levels, are used a prescribed constitutive parameters to tailor the meta-material unit-cell topology. The optimal material properties according to which the elastomeric track pad is designed with linear elastic material are identified in this work.