基于螺栓连接刚度的动力学模型修正

Dynamic model updating based on bolt connection stiffness

由于螺栓连接具有简单、可靠、安装方便等优点,在实际工程中被广泛采用。螺栓连接的连接刚度介于铰接和刚接之间,工程上一般直接处理为铰接或刚接,简化处理会影响栓接结构的仿真精度。为了提高栓接结构仿真的精度,更真实地反映栓接结构的动态特性,需要根据实验测试数据确定栓接的真实刚度。本文采用六自由度弹簧模拟螺栓连接,建立栓接结构的仿真模型:以栓接刚度为设计变量,以特征向量的数值仿真结果与实验测试结果的残差最小为目标,以固有频率的数值仿真结果与实验测试结果的残差为约束,建立了优化模型。通过迭代求解优化模型得到的栓接刚度,就是使数值仿真结果与实验测试结果相匹配的栓接刚度。用栓接结构的数值仿真结果替代实验测试数据,对修正后的栓接结构进行了静力和动力分析,分析了螺栓连接结构的数值仿真误差。数值算例表明:上述模型修正方法可以确定螺栓连接的真实刚度,能够提高螺栓连接结构的数值仿真精度;可为螺栓连接结构的理论分析和工程设计提供参考。

In practical engineering,bolt connection structures are widely used because of their advantages of simplicity,reliability and easy disassembly.The stiffness of bolted connection is between hinge and rigid connection,but it is usually treated as hinge or rigid connection directly in engineering.In order to improve the accuracy of numerical simulation of bolted connection structures and truly reflect the dynamic characteristics of bolted connection structures,it is necessary to determine the true stiffness of bolted connection according to the experimental data.The six degree of freedom spring is used to simulate the bolt connection to establish the simulation model of a bolt connection structure.The spring connection stiffness is taken as the design variable,the residual between the numerical simulation result and the experimental test result of the eigenvector is taken as the objective,and the residual of the natural frequency between numerical simulation result and the experimental test result is taken as the constraint to establish the optimization model.Solving the optimization model to get the spring stiffness is to make the numerical simulation results match the experimental test results of the bolt connection stiffness.The static and dynamic analysis of the modified bolt connection structure is carried out,and the numerical simulation error of the bolt connection structure is analyzed.Numerical examples show that the real stiffness of bolted connection can be determined by the model modification method,which can improve the numerical simulation accuracy of bolted connection structures,and provide theoretical basis and engineering experience for the precise modeling of bolted connection structures.