Research On Topology Optimization Design Method Of Lattice Structure Based On Selective Laser Melting

Lattice structure has excellent mechanical properties,such as light weight,high strength.It is widely used in various fields.However,the single homogeneous cells in lattice structure lead to the anisotropy of their mechanical properties and the low utilization rate of materials.Meanwhile,the traditional lattice structure preparation method still has many problems,such as complex process,high cost and low material utilization.These have become the bottleneck of the development and application of the lattice structure.Therefore,it is necessary to study the topology optimization design method of lattice structure based on the selective laser melting.Firstly,a topology optimization design method for lattice structures based on the diameter of rod elements in lattice structure is proposed in this paper,and the topology optimization is carried out by using the optimization method based on the ground structure method.On the basis of the original optimization model,the process constraint of selective laser melting technology is introduced,and the interior point method is applied to solve the whole optimization model.Then the sensitivity of the optimization model is calculated,and the influence of each parameter in the model on the optimization result is analyzed.Then,the process constraints on the fabrication of lattice structure by the selective laser melting are discussed.The characteristics of the SLM process and its influence on the lattice structure are analyzed.The forming quality and mechanical properties of rod units with different diameters and inclination angles under SLM process were studied.And the influence of the inclination angle and diameter of rod units on the mechanical properties and forming quality of rod units under SLM process was revealed.A set of prediction formula of rod units’ cross-sectional area based on SLM technology has been fitted.And the lattice structure can be corrected through the formula in the design stage,so as to minimize the error caused by SLM processing itself.Then this paper introduces the concrete realization of the lattice structure,which can optimize the topology of the continuum structure or lattice structure.At last,the topology optimization of a model of the shell of the penetration warhead of GBU-28 is carried out.And experimental samples are processed by SLM,and the optimization results are verified through comparative experiments.