六自由度振动台台体结构优化设计研究

在应用六自由度振动台进行高频振动测试试验时,若台体结构被激发产生共振,则会影响测试结果的准确性。为保证台体的共振频率在工作频带之外,同时使台体重量更轻,文章提出基于二级多点逼近算法的六自由度振动台台体结构优化方法。首先建立台体结构的有限元模型,并根据实际应用工况确定台体连接面法向位移约束的边界条件,以壳、梁单元的截面尺寸和外形半径大小为设计变量,建立以台体结构一阶固有频率和静强度为约束、质量最小为目标的模型。然后,利用二级多点逼近算法对模型进行尺寸优化,并以人机交互的方式实现外形半径的优化,得到满足约束条件的优化解。最后依据优化结果设计与制造出台体结构,并完成台体样机。该台体结构实现了轻量化设计要求并应用于振动试验,验证了该结构优化方法的有效性。

Structural optimization design of 6-DOF shaker's table

When a shaker of six degrees of freedom (6-DOF) is applied in a high frequency vibration test, the table of the shaker might easily be in the state of resonance, which will greatly influence the accuracy of the test results. To make the first-order natural frequency of the 6-DOF shaker''s table higher than the working frequency and reduce its mass, an optimization approach for the table based on the two-level multi-point approximation method is proposed. Firstly, the finite element model of the table is established, including the boundary conditions according to the actual working situation. Then, the structure model''s shell and beam properties and the radius of the shape are taken as the design variables, with the constraint of the first-order natural frequency and the static strength, a structure optimization model is established to minimize the mass. In the optimum solution, the two-level multi-point approximation method and the man-machine interactive method are, respectively, adopted in the size and shape optimizations. Based on the results after optimization, a prototype including the table structure is designed and manufactured. The structure can meet the lightweight design requirement and is used in the vibration test, thus this optimization approach is validated.