The nonlinear dynamic modeling by combining the equivalent linear mechanics with the multi-objective optimization algorithm is proposed to describe the nonlinear behaviors of the joint interfaces. The joint interfaces are simplified as the equivalent virtual material or linear spring–damper element. The genetic algorithm for multi-objective optimization is then used to identify the mechanical properties of the equivalent joint by minimizing the error between the simulated dynamic characteristics and the experimental results, including the modal frequencies of the bolted joint beam and the frequency response functions (FRFs) of the rubber isolation system. The FRFs are divided into several subsections with frequency-varied dynamic properties of the joint to consider the nonlinear dynamic behaviors, and the effects of subsection number and excitation amplitudes on the FRFs are also investigated. The results show that the simulated dynamic characteristics of modal frequencies and FRFs agree well with the experimental results. With the increase in the subsection number, the simulated FRFs agree better with the experimental results, indicating a good performance of modeling the nonlinear dynamic behaviors of the joint interfaces forced by different excitation amplitudes. Larger excitation amplitudes will decrease the joint stiffness.

中文翻译：

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等效线性力学与多目标优化相结合的联合界面非线性动力学建模

提出了将等效线性力学与多目标优化算法相结合的非线性动力学建模方法，以描述关节界面的非线性行为。关节接口简化为等效的虚拟材料或线性弹簧阻尼器元件。然后，通过将模拟动态特性与实验结果（包括螺栓连接梁的模态频率和频率响应函数，FRF）之间的误差最小化，使用多目标优化的遗传算法来识别等效接头的机械性能。 ）的橡胶隔离系统。FRF分为具有关节频率可变动态特性的几个小节，以考虑非线性动力学行为，并研究了分段数和激励幅度对FRF的影响。结果表明，模态频率和FRF的动态特性与实验结果吻合良好。随着分段数的增加，模拟的FRF与实验结果更好地吻合，这表明在模拟由不同激励幅度引起的关节界面的非线性动力学行为方面表现出良好的性能。较大的激励幅度将降低接头刚度。说明了对由不同激励幅度强迫的关节界面的非线性动力学行为建模的良好性能。较大的激励幅度将降低接头刚度。说明了对由不同激励幅度强迫的关节界面的非线性动力学行为建模的良好性能。较大的激励幅度将降低接头刚度。