改进的小损伤结构动力学有限元建模方法

在遗传算法或神经网络方法识别结构损伤位置和程度时,都是基于少量的在线测量的损伤结构振动响应数据和大量的模型仿真数据来实现的,因而建立高效和精确的损伤结构动力学有限元模型,以便仿真获得损伤结构的大量动力学响应数据是十分重要的基础前提工作。本文针对ANSYS结构分析软件在建立结构小损伤有限元动力学模型存在两个关键问题,结构损伤处直接网格划分的计算结果误差和网格节省问题,以结构损伤振动检测的实际需要为出发点,提出了建立含小损伤结构的ANSYS动力学建模技术,研究了结构局部小损伤及其位置与所在处单元刚度矩阵变化的数量关系。

Improved Dynamical Modeling Method for Structure with Small Damage

The existing methods for structural damage indentification,such as GA algorithms and neural networks technology,are usually implemented based on few measured data and a large number of simulation data from structural vibration responses.Construction of an acurate and efficient dynamics model for a structure with different damage becomes an important precondition,thus plentiful simulation data of structural vibration response can be acquired using the dynamics model of the structure with damage.There are two problems during direct meshing small structural damage in FEM modeling,i.e.,excessive gridding number and unavoidable errors from different(meshing) for the same damaged structure.To solve these two problems,an improved modeling method based on modifying element stiffness matrix at damage position is presented,and corresponding algorithm for damaged element stiffness matix is adopted.The influence of damage position and constraint conditions on the modification coefficient for small structural damage is simultaneously discussed.