Finite Element Analysis Investigating the Sliding Contact of a Shape Memory Alloy Substrate
Abstract
Recent experimental wear tests have demonstrated that shape memory alloys offer better wear
resistance than conventional wear resistant materials and therefore make them ideal candidates
as tribological materials. The wear resistance of shape memory alloys has been attributed to its
pseudoelasticity and high yield strength. To date however, an extensive computational study that
simulates the contact behavior of these alloys during a typical sliding wear process has not been
investigated.
This study uses the finite element method to analyze the sliding contact behavior between a
rigid cylinder and a two dimensional shape memory alloy semi-infinite half-space. An experimentally
validated constitutive model is used to capture the pseudoelastic effect exhibited by these
alloys. The finite element contact model is validated with closed form solutions for well known
normal and sliding elastic contact problems. Parametric studies involving key shape memory alloy
material parameters (maximum recoverable transformation strain, the inherent difference between
the elastic moduli of martensite and austenite phase, various isothermal loading paths) and coefficients
of friction are conducted to study the effects on the sliding response. It is shown that
the sliding response of SMAs is strongly temperature dependent, with significant residual stresses
present in the half-space at temperatures below the austenitic finish temperature. An increase in
the maximum transformation strain causes the stress distribution to be spread over a wider area and
causes a significant decrease in the maximum von Mises stress in the half-space. The ability of
shape memory alloys to undergo a stress induced transformation to a more compliant phase, also
causes a reduction in the Mises stress and further demonstrates why pseudoelastic SMAs offer
better wear resistance that conventional wear resistant materials.
Citation
Fernandes, Ralston Ignatius Tarsico (2018). Finite Element Analysis Investigating the Sliding Contact of a Shape Memory Alloy Substrate. Master's thesis, Texas A & M University. Available electronically from https : / /hdl .handle .net /1969 .1 /174065.