Elastic mechanics solution of thermal expansion of bi-material curved beam and its application to negative thermal expansion metamaterials

Abstract

Thermal stress impacts various engineering fields significantly, such as aerospace and precision instruments. This adverse effect can be greatly reduced, if not eliminated, by the application of micro-thermal expansion materials, and bi-material beams are widely utilized in the design of micro-thermal expansion structures, thereby exhibiting great application potentials. The elasticity solution of bi-material curved beam under free thermal expansion has been proposed by scholars. Based on this solution, the simplified form is proposed in this paper, and extended to the case where the rotation angles at both ends of the circular arc are constrained under thermal loads. Besides, the geometric parameters and the nonlinear problems of the thermal expansion of bi-material curved beam are analyzed. In addition, a novel type of negative thermal expansion material has been designed by applying the bi-material curved beam to the tetra chiral and anti-tetra chiral materials. The proposed material has greater negative thermal expansion effect than the traditional tetra and anti-tetra chiral materials that are with straight beams.

Impact resistance analysis of a dual-constituent negative Poisson’s ratio lattice metamaterial with tailorable coefficient of thermal expansion

“…This has stimulated researchers' interest in the study of artificial metamaterials capable of presenting zero or negative coefficients of thermal expansion (ZCTE or NCTE). These properties can often be obtained by compositing two or more materials with different CTE and by varying the material ratio or performing fine microstructure design [20][21][22][23][24][25][26]. Miller [27] first introduced two materials with different CTEs into a triangular unit cell to achieve CTE regulation in the vertical direction of the structure, and then Grima [28] assigned each of the three edges of the triangular unit cell to materials with different CTEs, further expanded the CTE tuning range of the triangular structure.…”