Stress relaxation behavior of 3D printed silicone rubber foams with different topologies under uniaxial compressive load

Abstract

3D printed elastomeric foams present good potential for mechanical application and their stress relaxation behaviors are critical for engineering performance. In this work, polydimethylsiloxane (PDMS) foams with simple tetragonal (ST) and face-centered tetragonal (FCT) structures were printed and present different stress relaxation behaviors. The ST foam had a similar stress relaxation rate to that of the stochastic foam (15–16%), whereas the FCT foam had a lower stress relaxation rate (10%). The ST foam had high local stress concentrations under compression, because it deformed by uniaxial buckling deformation, leading to high stress relaxation of the PDMS matrix. In contrast, the stress distribution was more uniform in the FCT foam due to its bending deformation under compression. Thus, the compressive deformation mechanism of the printed topology greatly affects the stress relaxation properties. This finding provides an important guide for the design of elastomeric foams with low stress relaxation for high performance applications.