Mechanical Property Analysis And Optimization Of Microstructures Based On Homogenization

Microstructure refers to the geometry structures whose size are small compared with the whole model.Researchers applied microstructure to design and manufacture metamaterials which greatly expand the physical property space of materials.Metamaterials realize the physical performance that cannot be met by homogeneous materials,such as lightweight and high strength required for aerospace components,energy absorption performance required by automobile industry,negative Poisson’s ratio required in biomedical field Material transport performance,etc.In recent years,researchers designed various microstructures,and used them for different applications.Different forms of microstructure are designed,such as truss-based microstructures,shell-based microstructures,foam microstructures,etc.Each microstructure has their own performance characteristics and application scenarios.Researchers generally used experimental method or finite element analysis method to obtain the mechanical properties of microstructures.In experimental method,people manufactured the sample unit composed of periodic arrangement of microstructure,and carried out uniaxial compression or tensile test on the sample unit using universal testing machine to obtain its mechanical properties.In the finite element analysis method,researchers used finite element analysis software such as ABAQUS and ANSYS.Applying equivalent boundary conditions of uniaxial compression or tension to the sample unit composed of periodic arrangement of microstructure,software simulated its deformation then obtain its mechanical properties.The experimental method has high requirements for manufacturing machines,experimental instruments and experimental methods.In addition,the manufacturing and experimental time is long.The finite element analysis method simulates the microstructure sample unit,which needs large-scale calculation and requires a lot of time.In order to obtain the mechanical properties of microstructure quickly,accurately and comprehensively,the homogenization method is used to analyze the mechanical properties of various types of microstructures.We obtain the equivalent Young’s modulus,shear modulus,Poisson’s ratio,compressive strength and shear strength of microstructure,and show the elastic anisotropy and stress distribution of microstructure,which gives a comprehensive analysis and comprehensive understanding of the mechanical properties of microstructure.For the truss-based microstructures,researchers have used parametric method to modeling them and optimized its mechanical properties,such as optimizing the structure to achieve the target elastic properties,isotropic elasticity and avoiding stress concentration and so on.However,the existing work lacks the parametric description of sheet-based microstructures and the optimization of its mechanical properties.In order to explore the high stiffness and high strength of sheet-based microstructures.Inspired by the hollow rod structure,this thesis describes the sheet-based microstructure parametrically based on the truss-based microstructures and generates a series of sheet-based microstructures with different topologies.And then optimizes the microstructures to a target mechanical property.