Design And Performance Test Of Insert Joints For Sandwich Structures Based On Topology Optimization

Sandwich structure has high specific stiffness,high specific strength,high designability and multi-function integration potential,which is one of the research hotspots in the field of mechanics and aerospace.However,the immature joining technology restricts the development and application of sandwich structure.The unique topological configuration of sandwich structure makes it difficult to transfer the concentrated load caused by the joint.Due to the lack of systematic theoretical analysis,the relationship between the bearing capacity and structural parameters of sandwich structure joint is still unclear.Therefore,this dissertation focuses on the design,fabrication and mechanical properties of insert joints for sandwich structures,analyzes the stiffness and load transfer path of the sandwich structure under concentrated load,and provides theoretical and technical support for the engineering application of the sandwich structure.The mechanical behavior of surface joint of three-dimensional honeycomb sandwich structure is studied.The deformation mechanism of the structure is systematically analyzed by numerical simulation,which lays a foundation for the optimization and performance characterization of the insert joints connection.The finite element software is used to optimize the surface joint of the honeycomb sandwich structure.The optimized and intial specimens are manufactured by 3D printing technology.The mechanical properties of the surface joint of the specimens are tested by normal tensile test,which proves the rationality of the optimization.According to the primary load forms of the boundary joint of honeycomb sandwich structure,the mechanical behavior of the boundary insert joint of the honeycomb sandwich structure is studied.The mechanical properties of the structure are systematically analyzed by numerical simulation.The boundary insert joint of honeycomb sandwich structure is locally optimized by using finite element software.The required specimens are manufactured by using 3D printing technology.Through the in-plane tensile test at the boundary of the structure,the bearing capacity of the structure is tested.And the reliability of the optimization of the boundary insert joint is verified by combining the numerical simulation and experimental test.The mechanical behavior of the lattice sandwich structure under different loads has been systematically studied.Through numerical simulation,the mechanical properties of the two-dimensional lattice sandwich structure under the normal tension and in-plane shear are respectively analyzed.The topology optimization method is used to locally optimize the insert,and the specific stiffness of the optimized structure is analyzed and calculated.The mechanical properties of three-dimensional lattice sandwich structure are studied.The stiffness of the lattice sandwich structure in the normal tension is analyzed.The connected prismatic insert is optimized and the model for the optimized structure is established.The rationality of the optimization is verified by numerical simulation.