The Design And Characterization Of Tailorable Thermal Expansion Structures

The thermal deformation of the structure will bring the problem of the stability of the engineering structure and will affect the measurement accuracy of precision equipment.The tailorable thermal expansion structure,due to its good shape stability and tailorable thermal expansion coefficient,can solve the problems caused by the thermal deformation of the structure.And the tailorable thermal expansion structure is being widely concerned by scholars abroad.However,there are relatively few related works on the design,manufacture and testing of tailorable thermal structures.The negative Poisson’s ratio metamaterial is also because of its unique nature of the negative Poisson’s ratio effect,which has caused extensive research by scholars.Replacing some members in the negative Poisson’s ratio metamaterial structure with a high thermal expansion coefficient material can make Negative Poisson’s ratio metamaterials have negative thermal expansion properties.This paper draws on the related research results of the existing tailorable thermal expansion structure and negative Poisson’s ratio structure,designs the tailorable thermal expansion structure based on the negative Poisson’s ratio cell,and uses the negative Poisson’s ratio structure’s negative Poisson’s ratio effect.The tailorable thermal expansion of the structure has both negative Poisson’s ratio and adjustable thermal expansion properties.The thermal expansion characteristics and mechanical characteristics of the thermal expansion-controllable structure were studied by numerical simulation.Mainly include the following:An tailorable thermal expansion cell structure consisting of a star-shaped negative Poisson’s ratio cell and a hexagonal positive Poisson’s ratio cell-a negative Poisson’s ratio unit with tailorable thermal expansion is designed.The composition of linear rods expands the structural unit array into a planar lattice structure.The influence of the geometric parameters and material distribution of the structural configuration on the equivalent thermal expansion coefficient of the structure is studied.The results of numerical simulation research show that by changing the structural parameters,it is possible to make the structure exhibits a positive or negative structural equivalent thermal expansion coefficient.The mechanical properties such as deformation and stress distribution of the structure under the action of uniform temperature field are analyzed and discussed.Based on this linear structure of negative Poisson’s ratio adjustable thermal expansion structure,a curved structure tailorable thermal expand structure is developed,which is the concave rods are replaced with arc curved rods with different radii of curvature.The effects of different structural geometric parameters and material distribution on the thermal expansion properties of the structure were studied.The numerical results prove that changing the geometric parameters and material properties of the structure can make the structure exhibit adjustable thermal expansion characteristics,and studied the structure’s mechanical problems of structural deformation and stress distribution under the effect of uniform temperature field.At the same time,this paper also uses the numerical method to study the equivalent compression stiffness and deformation failure mode of the negative Poisson’s ratio tailorable thermal expansion structure and the curved-edge tailorable thermal expansion structure under the action of compressive load,and compares the equivalent of the two structures’ s effective compression stiffness and its influencing factors.