Dynamic tests and model updating of nonlinear beam structures with bolted joints
Highlights•The derivation process of force-displacement relationship is presented for the Iwan beam element. Then, the linear beam element and Iwan beam element are used to simulate the bolted cantilever beam structure.•The linear natural frequency of the structure is obtained by low-amplitude random white noise test, and the linear parameters is updated based on the sensitivity analysis method.•The nonlinear model updating method based on the instantaneous characteristics of the principal response components is proposed to update nonlinear model of the bolted cantilever beam, and the parameters of Iwan beam element is obtained.AbstractMechanical joints usually affect structural dynamic responses, leading to local nonlinear stiffness and damping. In this paper, hysteresis Iwan model is discussed in detail to describe nonlinear mechanical behaviors of contact surface. Based on adjusted Iwan model, the derivation process of force-displacement relationship is presented for Iwan beam element. Meanwhile, relevant experimental study on the dynamic behaviors of a cantilever beam with a bolted joint is performed. Linear beam element and Iwan beam element are used to simulate the bolted cantilever beam structure, and the corresponding structural dynamic responses are calculated by forward incremental displacement center difference method. Then, combined with the nonlinear structural model updating method based on the instantaneous characteristics of principal dynamic response components, the bolted cantilever beam structure is updated and the parameters of Iwan beam element are obtained. The updated results are in good agreement with the experimental results, that is, the feasibility and effectiveness of the proposed nonlinear structural model updating method are verified by comparing the updated responses and measured data.
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