A Study on the Dynamic Behavior of a Simply Supported Beam with Moving Masses and Cracks

J. Ocean Eng. Technol. 2003;17(6):47-52.

이동질량과 크랙을 가진 단순지지 보의 동특성에 관한 연구

윤한익,손인수,조정래

동의대학교 기계정보산업공학부,동의대학교 대학원 기계공학과,동의대학교 대학원 기계공학과

Keywords: Open Crack, Dynamic Behavior, Moving Mass, Strain Energy Density Function, Flexibility Matrix

핵심용어: 개구형 크랙, 동적특성, 이동질량, 변형률 에너지 밀도함수, 유연행렬

Abstract

To determine the effect of transverse open crack on the dynamic behavior of simply-supported Euler-Bernoulli beam with the moving masses, an iterative modal analysis approach is developed. The influence of depth and position of the crack in the beam, on the dynamic behavior of the simply supported beam system, have been studied by numerical method. The cracked section is represented by a local flexibility matrix, connecting two undamaged beam segments that is, the crack is modeled as a rotational spring. This flexibility matrix defines the relationship between the displacements and forces across the crack section, and is derived by applying a fundamental fracture mechanics theory. As the depth of the crack is increased, the mid-span deflection of the simply-supported beam, with the moving mass, is increased. The crack is positioned in the middle point of the pipe, and the mid-span defection of the simply-supported pipe represents maximum deflection.