Delamination Defects Impact On The Carrying Capacity Of The Laminated Cylindrical Shells

Laminated composite cylindrical shells are important structural components in the aerospace and other engineering industries.This is due to their advantages of high stifmess-to-weight ratios,superior fatigue properties,high specific modulus and large space for design.The Composite Material Laminate is more complex compared to the traditional metal structure,which inevitably leads to various kinds of defects during manufacturing and utilization-Delamination,which caused by multiple factors, is the most important and serious of these defects.For the delaminated composite laminated cylindrical shells, even the presence of local delaminations can lead to a reduction in structural strength, thus causing a reduction in the critical buckling load of the cylindrical shells.This paper deals with the modeling of delamination in laminated composite cylindrical shells based on the finite element method.Through a systematic study,the results of critical buckling load varying with respect to different delaminations have been obtained.The main work of this paper can be divided into four parts as follows:1. This paper introduces the geometrical model of the composite cylindrical shells,which include delaminations extend along the entire circumference, delaminations extend along the entire length and square delaminations, as well as the finite element model and the method for analysis of the delaminated laminated cylindrical shells. By comparing with the previous results, the effectiveness of the finite element model and the method for analysis has been verified.2. This paper discusses the effect of delaminations extend along the entire circumference on the critical buckling load of laminated cylindrical shells subjected to loading of axial compression and external pressure.lt gives results of how the critical buckling load changes with respect to different delamination length and studies the effect of depth and location of the delaminations extend along the entire circumference on the critical buckling load.Besides,how the critical buckling load varies with respect to more than one delaminated zone has also been researched.More details can be found in chapter2.3. This paper discusses the effect of delaminations extend along the entire length on the critical buckling load of laminated cylindrical shells subjected to loading of axial compression and external pressure.It gives results of how the critical buckling load changes with respect to different delamination height and depth, and systematically studies the effect of more than one zone of delamination extend along the entire length on the critical buckling load.Besides,how the critical buckling load varies with respect to different relative locations of delaminated zones has also been researched.More details can be found in chapter3.This paper discusses the effect of square delaminations on the critical buckling load of laminated cylindrical shells subjected to loading of axial compression and external pressure.How the critical buckling load of the cylindrical shells with square delaminations varies with respect to different sizes of delaminations.More details can be found in chapter4.