Abstract: A kirigami metamaterial with tunable auxetic property under large tensions and a design method for it. The kirigami metamaterial is composed of a plurality of square unit cells in orderly arrangement. The unit cells are arrayed in periodic, gradient and inhomogeneous layouts, corresponding to the kirigami metamaterials with homogeneous, gradient and inhomogeneous auxetic properties. The design method is as follows: Firstly, the heuristic design of the unit cell is obtained by using the structural optimization method for fully considering out-of-plane deformations. Secondly, the optimization result obtained from the above step is processed by geometric reconstruction and parametric modeling, and then the auxetic properties with different geometric parameters are obtained. Finally, the kirigami metamaterial is composed of a plurality of unit cells arrayed into a specific layout. The present invention can achieve a variety of tunable auxetic trends adjusted with the tensions by modifying the cut parameters.

Abstract: The present invention belongs to the technical fields of novel structure design and lattice material design, and refers to structures, lattice materials, and lattice cylindrical shells with simultaneous stretch- and compression-expanding property. First, use the local tension-compression asymmetry in the tension modulus and compression modulus generated by the contact nonlinearity of the tension springs to construct a type of 2D structures and lattice materials with stretch- and compression-expanding property. Then by assembling the 2D structures in different directions, 3D structures and lattice materials can be constructed. Meanwhile, a lattice cylindrical shell can also be constructed by using the 2D stretch- and compression-expanding structures as the unit cell.

Abstract: A TPMS microstructural material with holes and an optimization design method therefor are related to the technical fields of topology optimization, microstructural materials and 3D printing. TPMS is smooth, has a large specific surface area and good mechanical properties, and has a good application prospect in the field of microstructural material design. According to the optimization design method, an advanced design method, i.e., topology optimization, is applied to the microstructural material design based on TPMS. The method is to conduct topology optimization on a TPMS model, and then design the number, layout and shape of holes in a complete TPMS according to the results of topology optimization so as to obtain the microstructural material with different configurations. The material obtained has a higher utilization rate and a better lightweight property.

Abstract: The present invention belongs to the technical fields of novel structure design and lattice material design, and refers to structures, lattice materials, and lattice cylindrical shells with simultaneous stretch- and compression-expanding property. First, use the local tension-compression asymmetry in the tension modulus and compression modulus generated by the contact nonlinearity of the tension springs to construct a type of 2D structures and lattice materials with stretch- and compression-expanding property. Then by assembling the 2D structures in different directions, 3D structures and lattice materials can be constructed. Meanwhile, a lattice cylindrical shell can also be constructed by using the 2D stretch- and compression-expanding structures as the unit cell.

Abstract: A structural non-gradient topology optimization method based on a sequential Kriging surrogate model mainly comprises three parts: reduced series expansion of a material field of design domain, building of a non-gradient topology optimization model and solving optimization model using a sequential Kriging surrogate model algorithm. Design variables of the topology optimization problem are considerably reduced through the series expansion of a material-field function, and then the topology optimization problem involving fewer than 50 design variables can be effectively solved using the sequential Kriging surrogate model algorithm with an adaptive design space adjustment strategy. Without requiring the information of design sensitivity of a performance function, this method is suitable for solving complex multi-physical, multidisciplinary and highly nonlinear topology optimization problems.

Abstract: A structure topology optimization method based on material-field reduced series expansion is disclosed. A bounded material field that takes correlation into consideration is defined, the bounded material field is transmitted into a linear combination of a series of undetermined coefficients using a spectral decomposition method, these undetermined coefficients are used as design variables, an optimization model is built based on an element density interpolation model, the topology optimization problem is solved using a gradient-based or gradient-free algorithm, and then a topology configuration with clear boundaries is obtained efficiently. The method can substantially reduce the number of design variables in density method-based topology optimization, and has the natural advantage of completely avoiding the problems of mesh dependency and checkerboard patterns.

Abstract: A method for fixture shape optimization design of a space membrane structure for inhibiting wrinkling, and solves the problem that the space membrane structure is easy to generate a wrinkling phenomenon under the stretching effect of a traditional fixture. By optimizing the shape of the fixture and changing the loading boundary conditions, the minor principal stress of the unit in the membrane region is maximized and the distribution of the principal stress of the membrane is regulated. A global optimization algorithm is used to find a global optimal design, and then novel fixture forms with “arch” and “convex” boundaries are obtained, to achieve the purpose of completely simulating the wrinkling. The present invention not only inhibits the generation of the wrinkling in the membrane, but also avoids cutting the membrane and ensures that the membrane has large enough working area.

Abstract: The present invention proposes a design optimization method to prevent wrinkling of stretched membrane structures. It solves the problem of membrane wrinkling in a macro structure or a graphene structure under stretching loads. The membrane material distribution is found using a topology optimization technique that generates a design with curved boundaries or inner holes to eliminate wrinkles. The stress state of a membrane is regulated by restrict the minimum principal stress of each finite-element to a positive value. Such a method guarantees that wrinkling is prevented by accurately designing the shape of boundary and the layout of holes of the membrane. The optimization procedure is highly automated, and the efficiency of the wrinkle-free design for membrane structures can be guaranteed.