Influence of Hole Localization on Local and Global Dynamic Response of Thin-Walled Laminated Cantilever Beam.

Marcin Bochenski,Andrzej Teter,Jaroslaw Gawryluk

doi:10.3390/ma14237409

Abstract

In this study, we discuss the effects of the diameter and position of a hole on the dynamic response of a thin-walled cantilever beam made of carbon-epoxy laminate. Eigen-frequencies and corresponding global and local eigen-modes were considered, where deformations of the beam wall were dominant, without significant deformation of the beam axis. The study was focused on the circumferentially uniform stiffness (CUS) beam configuration. The laminate layers were arranged as [90/15(3)/90/15(3)/90]T. The finite element method was employed for numerical tests, using the Abaqus software package. Moreover, a few numerical results of the structure’s behaviour, with and without a hole, were verified experimentally. The experimental eigen-frequencies and the corresponding modes were obtained using an experimental modal analysis, comprising the LMS system with modal hammer. We found that the size and location of the hole affected the eigen-frequencies and corresponding modes. Furthermore, even a small hole in a beam could significantly change the shape of its local modes. The numerical and experimental results were observed to have high qualitative compliance.

Highlights

Thin-walled laminate structures with closed cross-sections are commonly used elements in aerospace, mechanical and civil engineering, for example, in aircraft wings, helicopter and wind turbine blades, etc
Laminate structures have a high strength-to-weight ratio, but they are sensitive to different types of damage
A laminated box-beam made of unidirectional carbon-epoxy prepreg with circumferentially uniform stiffness (CUS) beam configuration was considered

Summary

Introduction

Thin-walled laminate structures with closed cross-sections are commonly used elements in aerospace, mechanical and civil engineering, for example, in aircraft wings, helicopter and wind turbine blades, etc. A hole could appear in the structure because of high energy impact [1] and reduce its stiffness and inertia Changing these parameters influences the structure’s dynamic response. In paper [10], the nonlinear vibrations of composite beams subjected to harmonic excitation were determined, which were further used to study the sensitivity of selected vibration response parameters to damage. The impact of a hole-type damage on the dynamic response of a thinwalled laminated beam was investigated using small inputs generated by a modal hammer. This method is often used to test composite structures [15,16].

Object of the Study

Finite

Results and Discussion

Results

Conclusions