Transient Response of an Impacted Beam and Indirect Impact Force Identification Using Strain Measurements

Hyungsoon Park,Youn-Sik Park

doi:10.1155/1994/781574

Abstract

The impulse response functions (force-strain relations) for Euler–Bernoulli and Timoshenko beams are considered. The response of a beam to a transverse impact force, including reflection at the boundary, is obtained with the convolution approach using the impulse response function obtained by a Laplace transform and a numerical scheme. Using this relation, the impact force history is determined in the time domain and results are compared with those of Hertz's contact law. In the case of an arbitrary impact, the location of the impact force and the time history of the impact force can be found. In order to verify the proposed algorithm, measurements were taken using an impact hammer and a drop test of a steel ball. These results are compared with simulated ones.

Highlights

Impact is defined as a force of short duration acting on a structure; this causes a local response in the system
Impacts on the beam by a steel ball are tested and the reconstructed forces are compared with the results found using Hertz's contact law
Because the impact force cannot be measured in this case, the convolution result from the recovered force and the impulse response function between the predicted impact point and the measured point, x = 10 cm, is compared with the measured signal at x = 10 cm (Fig. 15)

Summary

Introduction

Impact is defined as a force of short duration acting on a structure; this causes a local response in the system. This article focuses on the transverse impact of a beam (Fig. 1) to investigate features of wave phenomena and to reconstruct the impact force from a measured strain signal using the impulse response function. In order to execute both response and force analysis, the impulse response function, which is the relationship between the force and strain, is obtained by using the wave propagation approach in the time domain.

Results

Conclusion