The effect of a negative Poisson’s ratio on thermal stresses in cellular metallic structures

Abstract

To investigate the influence of auxetic behavior on thermally induced stresses, finite element analysis simulations of the displacement and stress fields in locally heated three dimensional auxetic and cubic structures are compared. The simulations were carried out in Comsol for a cubic as well as a chiral array of 30 mm length in each spatial dimension (3 × 3 × 3 unit cells). The center cells of these arrays were heated for 20 s. For two boundary conditions (free and clamped), deformation mechanisms are analyzed. It is found, that the auxetic behavior can effectively reduce thermal stresses by internal node rotation and strut bending, especially for constrained (clamped) boundary conditions. A stress reduction of a factor of 3.3 in comparisons to a simple cubic cell array could be evaluated.

Design and Additive Manufacturing of 3D Phononic Band Gap Structures Based on Gradient Based Optimization

“…The selective electron beam melting (SEBM) process enables the production of very complex parts, such as cellular metals [ 39 ]. It has been shown that the process is suited to fabricate cellular auxetic structures with the ability to control relative density [ 40 , 41 , 42 , 43 ]. Furthermore, phononic band gap structures were produced by SEBM and the existence of the complete PBGs was already experimentally verified [ 21 , 44 ].…”

Experimental and numerical studies on a novel shape-memory alloy wire–woven trusses capable of undergoing large deformation

“…The model was built using solid elements (ABAQUS element type C3D8R with a mesh sweeping seed size of 0.2-0.3 mm, as shown in Figure 18(d) and (e)). The seed size was selected by the criterion of a maximum deviation of 3% of the maximum von Mises stress when the element size was halved (Adler et al, 2016). The material properties used in the simulation come from tensile test results of SMA wires.…”