A STUDY ON VIBRATION AND BUCKLING ANALYSIS OF CRACKED COMPOSITE BEAM

Chhaya Ahirwar; P.C. Diwan; Harsh kumar Ahirwar

Volume : VIII, Issue : II, February - 2019

A STUDY ON VIBRATION AND BUCKLING ANALYSIS OF CRACKED COMPOSITE BEAM

Chhaya Ahirwar, P. C. Diwan, Harsh Kumar Ahirwar

Abstract :

Cracks in structural members lead to local changes in their stiffness and dusttrap their static and dynamic nature is altered. The influence of cracks on dynamic characteristics value of material like common frequencies, modes of viation of structures has been the subject of many investigations. However studies related to nature of composite cracked structures subject to in–plane forces are scarce in literature. Present work deals with the viation and buckling analysis of a cantilever beam made from graphite fiber reinforced polyimide with a transverse one–edge non–propagating open damage using the finite element method. The uncracked parts of the beam are modeled by beam finite elements with three nodes and three degrees of freedom at the structure work. An „overall additional flexibility matrix‟ is added to the flexibility matrix of the corresponding non–damage composite beam element to obtain the total flexibility matrix, and therefore the stiffness matrix in line with previous studies. The viation of cracked composite beam is computed using the present formulation and is compared with the previous results. The effects of many parameters like crack location, crack depth, volume fraction of fibers and fibers orientations upon the changes of the natural frequencies of the beam are studied. It is found that, presence of crack in a beam decreases the natural frequency which is more pronounced when the crack is near the fixed support and the crack depth is more. The natural frequency of the cracked beam is found to be greater than at about 45% of volume fraction of fies and the frequency for any depth of crack increases with the increase of angle of filament. The static buckling load of a cracked complex beam is found to be decreasing with the presence of a damage and the decrease is more severe with increase in crack depth for any location of the crack. Furthermore, the buckling force of the beam decreased with increase in angle of the fies and is highest at 0 degree orientation.