机械结构边界条件动态设计方法研究

Boundary dynamical design method research for mechanical structures

仅通过边界条件的动态设计而不改变结构的内部参数 ,在一定条件下 ,使结构满足给定的多阶固有频率与振型的要求 .通过边界参数的改变量 ,建立了边界条件改变前后 2个系统之间的关系 ,并将上述关系由物理坐标转换至模态坐标 ,得到结构在新的边界条件下的特征方程 .在此基础上 ,采用逐步二次规划法 ,对边界参数进行了优化求解 .此外 ,研究了模态截尾对算法的影响以及补偿方法 .本文方法具有精度高、物理概念清晰。

A boundary dynamical design method is introduced to satisfy a structure's multi frequency and mode shape requirements by designing its boundary conditions under certain circumstances while the inner part of the structure is kept unchanged. The relationship between the original structure and the new one with changed boundary conditions is built on the difference between the boundary parameters. The eigenvalue equation was then obtained by transforming the coordinate system from physical domain to modal domain. Sequential quadratic programming was adopted to solve the boundary parameters optimization problem. The influence of modal truncation was also discussed and its related compensation method was suggested. The accuracy of the presented method was proved by examples. This method has a clear physical meaning and can be used in a wide variety of dynamical engineering design problems.