Parameter identification of lap-type joints based on Bouc–Wen–Bilinear model and event-driven steady-state response sensitivity method

The pursuit of accurately representing the frictional behavior of joint interfaces has led to the development of numerous Iwan models, each distinguished by its unique density function. However, deriving the density function that most accurately represents the frictional hysteresis in bolted joints is still a significant challenge, primarily due to epistemic uncertainties associated with interface characteristics. This paper proposes a novel Bouc–Wen–Bilinear (BWB) Iwan-type model, wherein the model parameters are identified directly from hysteretic curves rather than relying on specific density functions. This novel model simulates the micro-slip behavior of the joint interfaces by the Bouc–Wen model instead of the integral formulation of density functions. To calibrate lap-type joints, steady-state response data, accurately capturing the dominant friction mechanisms inherent in bolted joints, is integrated with an event-driven sensitivity analysis method, resulting in a tailored event-driven steady-state response sensitivity method. Furthermore, a normalization technique is proposed and incorporated into the tailored method to address the order-of-magnitude discrepancies between model parameters and response variables. Numerical simulations and experiment studies show that the proposed BWB model efficiently represents the frictional hysteresis of lap-type joints.