Progressive failure analysis of composite shells

Olcay, Yasemin
The objective of this thesis is to investigate the progressive failure behavior of laminated fiber reinforced composite shell structures under different loading conditions. The laminates are assumed to be orthotropic and the first order shear deformation theory is applied. Three-node layered flat-shell elements are used in the analysis. To verify the numerical results obtained, experimental and analytical results found in literature are compared with the outputs of the study, and the comparison is found to have shown good agreement with the previous work. Rectangular graphite/epoxy composite laminates under transverse loading are analyzed through several boundary conditions and stacking sequences. Maximum stress criteria, Hashin’s criteria and Tsai Wu criteria are employed to detect the failure and progressive failure methodology is be implemented according to instantaneous degradation approach. First ply failure, final failure loads, corresponding deformations and failure patterns are presented and compared.


Failure analysis of advanced composites under impact by cohesive zone method
Doğan, Oğuz; Parnas, Kemal Levend; Department of Mechanical Engineering (2013)
The main objective of this study is to investigate the delamination damage of laminated composites subjected to low velocity impact. Three-dimensional finite element analyses are conducted to determine delamination area, shape and location. The impact analysis is performed by using the explicit finite element method which uses the central difference rule to integrate the equations of motion through the time. The composite structures are modeled using eight-node solid elements. The critical interfaces betwee...
Experimental and numerical investigation of damage process in composite laminates under low-velocity impact
Topaç, Ömer Tanay; Çöker, Demirkan; Gürses, Ercan; Department of Aerospace Engineering (2016)
Damage sensitivity of composites under out-of-plane dynamic loading, and its limited detectability on a structure has long remained a prominent problem in industry. In this study, simulations are compared with the real-time damage formation scheme, with the aim of increasing confidence in failure predictions. Drop-weight impact experiments are carried out on a [0/90]_s CFRP beam laminate. Initiation and progression of damage, consisting of matrix cracks and delamination, are visualized via ultra-high-speed ...
Progressive interlaminar failure analysis in composite missile structures
Bartan Kumbasar, Büşra; Kayran, Altan; Department of Aerospace Engineering (2016)
Interlaminar damage in composite structures is very crucial because it may cause splitting of the layers and lead to progressive failure of the whole structure. Delamination initiation and progression must be predicted accurately to aid the design of composites structures. Objective of the thesis is to investigate the interlaminar progressive failure behavior of the composite wing of a missile manufactured by twill composite by finite element analysis and tests. For this purpose, before the analyses and tes...
Buckling, postbuckling and progressive failure anaylses of composite laminated plates under compressive loading
Namdar, Ömer; Darendeliler, Haluk; Department of Mechanical Engineering (2012)
The aim of this thesis is to investigate buckling, post-buckling behaviors and failure characteristics of composite laminated plates under compressive loading with the help of finite element method and experiments. In the finite element analyses, eigen value extraction method is used to determine the critical buckling loads and nonlinear Riks and Newton-Raphson methods are employed to obtain post-buckling behaviors and failure loads. The effects of geometric imperfection amplitude on buckling and post-buckl...
Numerical investigation of stiffened composite panel into buckling and post buckling under combined loading
Akay, Erkan; Yaman, Yavuz; Department of Aerospace Engineering (2015)
This thesis presents the investigation of buckling and post buckling behaviour of stiffened thin walled laminated composite aerospace structures subjected to combined in-plane axial and shear loadings. Due to the fact that the state of stress developing especially in the post-buckling stage is quite complicated under the combined loading, the necessary computational model is usually based on Finite Element Modelling (FEM). In this study, after verifying the FEM methodology and completing the sensitivity stu...
Citation Formats
Y. Olcay, “Progressive failure analysis of composite shells,” M.S. - Master of Science, Middle East Technical University, 2012.