基于刚-柔混合建模的时变结构动力学分析

Dynamic analysis of time-varying structure based on rigid-flexible hybrid modeling

为适应液压挖掘机高速、轻量化的要求,以具有时变固频特性的液压挖掘机工作装置为研究对象,提出了以角加速度判断时变结构的关键工况,利用刚性多体动力学和有限元方法对液压挖掘机在整个作业循环中的动力学特性进行建模和分析.分析了液压挖掘机工作装置在受力最大处的动态应力分布,并与传统刚性体模型的分析结果进行了比较.结果表明,刚-柔混合建模方法与刚性体建模方法相比,获得的位移和应力较小,反映出以往的设计偏于保守,为轻量化设计提供了依据.

In order to design lighter and faster hydraulic excavator, a rigid-flexible hybrid modeling method based on rigid multi-body dynamics and finite element method was put forward to study the dynamic characteristic of hydraulic excavator in its whole working cycle. The working equipment with characteristic of time-varying structure was taken as research object, and radial acceleration was computed as tags of key load. The dynamic response distribution of the working equipment in the case of maximal load was analyzed, and the results were compared with those of rigid body modeling method. Analysis results showed that compared with the rigid body model, the displacement and stress obtained by using rigid-flexible hybrid model were smaller. So the former design is conservative, and the method is helpful for light-weight design of hydraulic excavator.