Stiffness identification of boundary conditions by using thin-layer element for parameterization

Dong Jiang,Yu Tian,Yu Xu,Wu Yimeng

doi:10.21595/vp.2019.20841

Abstract

The stiffness of boundary conditions in mechanical structures is difficult to represent. A method is proposed to model the mechanical performance of the clamped boundary condition based on thin-layer element. Firstly, the contact surface of clamped boundary condition is parameterized by using isotropic thin-layer element to model the normal and tangential contact stiffness. Secondly, material parameter of thin-layer element is identified by using experimental modal data, parameter identification is transformed as an optimization problem. Experimental investigation is undertaken to verify the proposed method by employing an aluminum honeycomb panel, the numerical model of which is constructed by using the equivalent theory. Thin-layer elements with different properties are used to simulate the mechanical properties in different area of the boundary conditions, and the experimental modal data is adopted to identify the material parameters. Results show that the width to thickness ratio of the thin layer element has a great influence on the identification results.

Highlights

Investigations on modeling of boundary conditions have attracted interests of researchers [1, 2]
Boundary stiffness are simplified as spring models in the above researches, modeling difficulties will arise when apply spring models to complex structures, because spring element should be allocated in each boundary constraints, and the deficiency is obvious for modeling large contact surface
Until the numerical modal data satisfy the requirement of precision, the accurate contact surface material parameters are obtained

Summary

Introduction

Investigations on modeling of boundary conditions have attracted interests of researchers [1, 2]. The contact analysis for boundary conditions will be time consuming when apply to modeling of complex structures. Identification of the boundary conditions from experimental data is an effective solution to improve the modeling accuracy. Pabst and Hagedorn [6] proposed an inverse method to identify the boundary stiffness and damping parameters of a visco-elastically clamped beam by using modal data. STIFFNESS IDENTIFICATION OF BOUNDARY CONDITIONS BY USING THIN-LAYER ELEMENT FOR PARAMETERIZATION. Based on the basic theory of thin-layer element, this paper parameterized the contact surface of the clamped boundary. The elastic parameters of the thin-layer element are identified by using the experimental modal data. The influence of the weighted matrix and the ratio coefficient of the thin-layer element are investigated

Thin-layer element

Parameter identification

Case studies: a clamped honeycomb panel

Equivalent modeling

Findings

Conclusions