弱非线性和不确定性对结构动力学分析的影响

摘要

Structural nonlmeanfies and uncertainties are rommon phenomenon encountered in practical engineering structures. The influence of nonlinearities and uncertainties in engineering applications on structural dynamic analysis is discussed. A method separating nonlinearities from uncertainties through constant displacement and velocity tests is developed for establishing the accurate model as much as possible. Based, on the study of Validation Challenge of Structural Dynamics Problem developed by Sandia National Laboratories (2006), a simulated 3DOF mathematic model with nonlinear stiffness and damping behavior, together with the parameter variation is constructed. A Monte Carlo Simulation is used to generate a pool of simulated nonlinear models through which the method is illustrated and verified.%局部连接引起的弱非线性和加工制造公差引起的参数变化不确定性是许多工程结构的常见现象.针对弱非线性和参数变化不确定性对结构动力学分析的影响进行了讨论,提出了一种通过恒位移和恒速度响应的振动试验进行非线性建模,并用统计分析来处理不确定性,建立尽可能精确的数学模型进行结构动力学分析的处理方法.仿真实例是在对美国Sandia国家实验室2006年提出的“结构动力学问题的模型确认挑战”研究的基础上,建立的具有非线性刚度和非线性阻尼以及参数变化不确定性的三自由度集中质量模型,仿真结果验证了方法的有效性.