Nonlinear modeling of structures with bolted joints: A comparison of two approaches based on a time-domain and frequency-domain solver

Abstract

Motivated by the current demands in high-performance structural analysis, and by a need to better model systems with localized nonlinearities, analysts have developed a number of different approaches for modeling and simulating the dynamics of a bolted-joint structure. However, it is still unclear which approach might be most effective for a given system or set of conditions. To better grasp their similarities and differences, this paper presents a numerical benchmark that assesses how well two diametrically differing joint modeling approaches -a time-domain wholejoint approach and a frequency-domain node-to-node approach -predict and simulate a mechanical joint. These approaches were applied to model the Brake-Reuß beam, a prismatic structure comprised of two beams with a bolted joint interface. The two approaches were validated first by updating the models to reproduce the nonlinear response for the first bending mode of an experimental Brake-Reuß beam. Afterwards, the tuned models were evaluated on their ability to predict the nonlinearity in the dynamic response for the second and third bending modes. The results show that the two joint modeling approaches perform about equally as well in simulating the Brake-Reuß beam. In addition, the exposition highlights improvements that were made in each method during the course of this work and reveal further challenges in advancing the state-of-the-art.

The Direct Integration Method with Virtual Initial Conditions on the Free and Forced Vibration of a System with Hysteretic Damping

“…In the analytical solution, the divergent member can be omitted to obtain the exact solution of Equation (14). However, the direct integration solution converges to Equation (12). Therefore, it is crucial to make Equation (12) equal to Equation (14).…”

“…The complementary solution is the free vibration response given by Equation (12). The complete solution is the sum of the complementary and particular solutions.…”

“…The frequency domain approach solves the hysteretic damping system by using the Fourier transform for the equation of motion [9][10][11], but it has two main drawbacks [12,13]. (1) Part of transient response may be neglected which may underestimate the response at the initial time and (2) in theory, it is only applicable for the linear elastic system due to the application of the superposition principle, so it cannot be used to analyze the true nonlinear response.…”

On an improved adaptive reduced-order model for the computation of steady-state vibrations in large-scale non-conservative systems with friction joints

“…Other types of nonlinearities can exist such as geometric nonlinearities, material nonlinearities and aerodynamic forces, but they still remain less important than friction joints, especially for the applications to turbo-machinery [1]. The contact friction can result in a significant reduction in the global stiffness of the whole structure through the relative motion on the joint interface, which also introduces amplitude-dependent damping [11,16,19,28]. For an accurate prediction of the dynamic behavior of the assembly, the dynamics of the joint of interest must be captured accurately [6].…”

On the Use of Ultrasound Waves to Monitor the Local Dynamics of Friction Joints

“…These modelling approaches must be validated against experimental results, to confirm the quality of the models and their reliability for the analysis of complex nonlinear structures. Despite some validations performed on the global scale which looks at A. Fantetti a.fantetti@imperial.ac.uk 1 Imperial College London, London, England the nonlinear dynamic response of the assembled system [9,10], experimental techniques which can be used to improve the understanding of local joint dynamics are still a rather unexplored field of research. One of the main reasons for this lack of local experiments is the lack of a suitable technique which is able to capture what is happening locally without interfering with the contact itself.…”