Implicit Inverse Force Identification Method of Acoustic Liquid-structure Interaction Finite Element Model

TL;DR

This paper introduces an implicit inverse force identification method for vibroacoustic FE models that improves stability, reduces degrees of freedom, and handles noise, enabling accurate force reconstruction in fluid-structure systems.

Contribution

It proposes a novel inverse force identification approach combining implicit time integration, reduced-order modeling, and regularization for vibroacoustic FE models.

Findings

Accurately identifies unmeasured forces in simulations and experiments.

Demonstrates improved stability and efficiency over existing methods.

Effectively reconstructs response fields in fluid-structure interaction models.

Abstract

The two-field vibroacoustic finite-element (FE) model requires a relatively large number of degrees of freedom compared to the monophysics model, and the conventional force identification method for structural vibration can be adjusted for multiphysics problems. In this study, an effective inverse force identification method for an FE vibroacoustic interaction model of an interior fluid-structure system was proposed. The method consists of: (1) implicit inverse force identification based on the Newmark-$\beta$ time integration algorithm for stability and efficiency, (2) second-order ordinary differential formulation by avoiding the state-space form causing large degrees of freedom, (3) projection-based multiphysics reduced-order modeling for further reduction of degrees of freedom, and (4) Tikhonov regularization to alleviate the measurement noise. The proposed method can accurately identify the unmeasured applied forces on the in situ application and concurrently reconstruct the response fields. The accuracy, stability, and computational efficiency of the proposed method were evaluated using numerical models and an experimental testbed. A comparative study with the augmented Kalman filter method was performed to evaluate its relative performance.