Research On Topology Optimization Method Based On Nodal Density

Compliant mechanisms are the type of mechanisms that use elastic deformation of flexible members to transfer force, motion or energy. These devices have good prospects in areas such as Micro-Electro-Mechanical Systems, precision position and smart structures due to their advantages such as elimination of friction and wear.An optimal topology design based on finite element method for compliant mechanism used in micro-manipulation system is studied. The following aspects are studied in this dissertation: the numerical instabilities in topology optimization results, nodal density method, multiple inputs and multiple outputs compliant mechanism and suppression of the output coupling terms.In this dissertation, a new method using nodal density as design variable of continuum topology optimization is studied to resolve the checkerboard pattern. This method ensures C₀ continuity of density field in a fixed design domain, which prevents the checkerboard pattern problem. Numerical examples are presented to support the proposed design method which can effectively eliminate the numerical instabilities, such as checkerboard and mesh-dependency in topology optimization results. A clear structures is result is gained, and certain number of gridding is necessary.The mathematical model of topology optimization for multiple inputs and multiple outputs compliant mechanisms is established based on the principle of mutual energy, in which, the ratio of mutual energy to strain energy of the mechanism is regarded as the objective function. The analytical expression of sensitivity based on nodal density for multiple inputs and multiple outputs compliant mechanisms is deduced in detail. Outputs coupling terms is considered in this paper, make the control of multiple ...more easy.The 2D micro actuator that can be used in micro stage is designed by using topology optimization of multiple inputs and multiple outputs compliant mechanisms with multi load cases, the mathematical model is established, the analytical expression of sensitivity is deduced and the result of topology optimization is compared. The experimental results show that properties of the micro actuator can be fulfilled the designing demand.The paper is support by the Fund of Young Teacher of DUT 2006.