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

Abstract

Joints are commonly used in many largescale engineering systems to ease assembly, and ensure structural integrity and effective load transmission. Most joints are designed around friction interfaces, which can transmit large static forces, but tend to introduce stick-slip transition during vibrations, leading to a nonlinear dynamic system. Tools for the complex numerical prediction of such nonlinear systems are available today, but their use for large-scale applications is regularly prevented by high computational cost. To address this issue, a novel adaptive reduced-order model (ROM) has recently been developed, significantly decreasing the computational time for such high fidelity simulations. Although highly effective, significant improvements to the proposed approach is presented and demonstrated in this paper, further increasing the efficiency of the ROM. An energy-based error estimator was developed and integrated into the nonlinear spectral analysis, leading to a significantly higher computational speed by removing insignificant static modes from the stuck contact nodes in the original reduced basis, and improving the computational accuracy by eliminating numerical noise. The effectiveness of the new approach was shown on an industrial

Computation of damped nonlinear normal modes for large scale nonlinear systems in a self-adaptive modal subspace

“…To overcome above-mentioned challenges, improved sub-structuring methods are needed to enhance the computational performance for the calculation of dNNMs. Recently, an adaptive component mode synthesis method was put forward by Yuan providing a significant computational improvement for large scale systems with friction joints [35][36][37]. The method allows the set of static modes in classical CMS reduced basis to update automatically according to the real-time contact conditions on the interface.…”

“…This adaptive ROM can be conveniently integrated with the harmonic balance method (HBM) to obtain the most interesting steady-state response. The original adaptive algorithm was further improved by introducing an energy-based error estimator [37]. It can be effectively used as a monitoring indicator to update the set of reduced basis through adding or removing associated static modes during the online computation.…”

A Reduced Order Model for Joint Assemblies by Hyper-Reduction and Model-Driven Sampling

“…Speedups ranging from 50-100 have been reported considering the cost per iteration for a test case with relatively restrictive assumptions regarding contact conditions. A further improvement was presented in [23] that excludes numerical noise, as well as nodes that are dominated by sticking behavior, from influencing the choice of reduced interface DOFs. To contrast our work with existing methods, we regard that relative to [21], we explore employing a HR technique that retains the original interfacial mesh, and in relation to [22,23], we test considering only one reduced set of elements for the nonlinear computations at all frequency points.…”

On the use of the GP-NARX model for predicting hysteresis effects of bolted joint structures

“…However, handling contact problems involves complex nonlinearities governed by micro and mesoscale parameters, e. g., geometry, roughness, and contact pressure [5], which considerably increases the complexity and computational cost of these numerical models. Some other nu-merical tools have been developed in recent years to accelerate such simulations, including quasi-static modal analysis (QSMA) [6,7,8], reduced-order models (ROMs) [9,10], and substructuring techniques based on the spatial decomposition of the structure in a local basis partitioned into linear and nonlinear subdomains, with the latter encompasses the region around the lap-type bolted joint [11,12].…”