Topological Optimization Design Of Multi Degree Of Freedom Compliant Mechanisms With Large Geometric Deformation

Compliant mechanisms often require large displacements and large rotations to improve the performance of the mechanism,and how to design and improve the performance of Compliant mechanisms has become one of the difficult research areas.The rapid development of computer technology has led to the mature use of topology optimisation as a design tool for structural optimisation,and the use of topology optimisation is very scientific and efficient for the design of flexible mechanisms.The current topology optimisation method for flexible mechanisms is often based on the theory of small deformations of the linear elastic model.For the topology optimisation of large deformation flexible mechanisms the geometric non-linear effects must be taken into account.Therefore,this paper mainly investigates the geometric nonlinear topology optimization theory and the topology optimization design method for large deformation flexible mechanism,the main contents and works are as follows:(1)Geometrically non-linear topology optimisation theory for continuum structures.In view of the existing topological optimisation design methods for linear elastic models which do not take into account non-linear effects,the linear finite element part is further extended to non-linear finite elements based on the mechanics of continuous media,and non-linear finite element equilibrium equations are established.The two-way asymptotic structure optimisation method is the basic method for topology optimisation,summarising and generalising and realising the complete theory and process of non-linear topology optimisation.The effectiveness of the nonlinear topology optimization algorithm is demonstrated through classical arithmetic examples,laying the theoretical foundation for the later research.(2)A nonlinear topology optimization method for continuum structure geometry based on the Binary Hunter Prey Optimization algorithm.In order to solve the problems of the BESO method for nonlinear topology optimization,such as the tendency to fall into local optima and fail to obtain optimal topological configurations,and the low computational efficiency of the meta-heuristic algorithm for solving nonlinear topology optimization models.Firstly,the existing standard HPO algorithm is used to construct the binary HPO(BHPO)algorithm by discrete binary processing with the S-shape conversion function;secondly,the cell structure is defined by double encoding,and the sensitivity information is used as the fitness function of the BHPO algorithm to perform a semi-random search for the optimal topological configuration to establish the BHPO-BESO nonlinear topological optimization theory;finally,a typical Finally,the algorithm is tested with a typical case,and the results prove that BHPO-BESO can find a better topological configuration and is more computationally efficient than the BESO method,which can solve the above problems.(3)Nonlinear topology optimization method based on adaptive evolution rate.In order to solve the problem of lower computational efficiency due to constant evolutionary values in nonlinear topology optimization,two adaptive evolutionary rate models based on S-type functions and V-type functions are used to dynamically control the evolutionary rate in bi-directional progressive structure method topology optimization,in order to improve the computational efficiency of topology optimization.It is proved that the adaptive evolution rate model based on the S-type function is more effective after a typical calculation.(4)Topology optimization design of large deformation flexible clamps.This chapter takes a planar two-dimensional flexible clamp as an example,solves its optimal topology based on the geometric non-linear topology optimisation theory in this paper,and transforms it into a three-dimensional model by stretching.In order to allow the flexible clamp to produce as large a deformation of displacement as possible,the optimal topology configuration is structurally redesigned.The rationality of the designed structure is verified by finite element simulation,the flexible clamp is manufactured by 3D additive manufacturing technology,and finally the mechanical properties are tested and compared with the finite element simulation results to prove the effectiveness of the geometric non-linear topology optimisation of this paper,and the large displacement output of the flexible clamp is achieved by the redesigned structure.