类蜂窝复合夹层结构的力学特性及其在精密机床上的应用

Mechanical Properties of Honeycomb Composite Sandwich Structure with Applications to Precision Machine Tools

为提高加工中心中立柱的静、动刚度及热刚度,提出一种类蜂窝胞元结构,并应用该结构对加工中心的关键部件进行重新设计。首先,针对蜂窝结构在共面方向承载力不足的问题,以传统六边形蜂窝胞元为对象,在外侧构建保护壁,构成类蜂窝结构,力学特性及仿真分析表明,强化后的结构具有更好的比刚度和承载性。其次,将机床立柱结构分为横梁和立柱两部分,将类蜂窝填充结构分别与"米"字形或"井"字形填充结构进行了对比分析,从定性和定量的角度评判方案的优劣。最后,计算了刀具在实际工况下的受力及主轴箱、导轨等处的生热状况,将力载荷和热载荷施加在立柱上,并对重新设计后的立柱进行了静、动力学分析及散热性能分析。结果表明:较"井"字形填充结构,类蜂窝填充结构的立柱质量减小了4.21%,沿z轴的变形下降了39.5%,一阶固有频率提高了29.22%,热稳态时间减少了81.39%。

To improve the static, dynamic and thermal stiffness of a machining center column, the honeycomb cell structure is introduced in the redesign of the key parts of the machining center. For the insufficient bearing capacity of honeycomb structure in the coplanar direction of the traditional hexagonal honeycomb cell, the protective wall is constructed on the outer side of the honeycomb cell to form the honeycomb-like structure. Simulations and the mechanical property analysis indicate the better specific stiffness and bearing capacity of the strengthened structure. The properties of the column filled with star-shape or #-shape and honeycomb structures are compared, the advantages and disadvantages of this redesign scheme are evaluated from the qualitative and quantitative aspects. The suffering force of the cutter under actual working condition and the heat generation of the spindle box and guide rail are calculated. The force and heat loads are exerted to the column, and the static, dynamic and heat dissipation performances of the redesigned column structure are analyzed. The results show that compared with the #-shape rib-filled column, the mass of the honeycomb-filled column is reduced by 4.21%, the deformation along the z-axis is reduced by 39.5%, the first-order natural frequency is heightened by 29.22%, and the thermal steady-state time is reduced by 81.39%.