Failure analysis of advanced composites under impact by cohesive zone method

Download

index.pdf

Date

2013

Author

Doğan, Oğuz

Metadata

Show full item record

Item Usage Stats

231
views

112
downloads

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 between layers is represented by special interface elements based on Cohesive Zone Method (CZM). A combined approach considering damage initiation and damage growth phases in a single model is utilized in this method. The linear elastic and linear softening behavior is applied for these interface elements. A stress based failure criterion and damage mechanics approach are used to simulate initiation and propagation of delamination, respectively. The analyses are divided into two main sections involving the validation of computational model and parametric studies. The eight-node brick element is verified without delamination damage. Then, the model with delamination damage is validated by experimental results from literature. The verified model is adapted for the curved laminates and a parametric study is conducted in order to determine the effect of curvature on the delamination damage. Additionally, the effect of element size on delamination damage is discussed.

Subject Keywords

Laminated materials., Composite materials, Materials, Fracture mechanics.

URI

http://etd.lib.metu.edu.tr/upload/12616306/index.pdf
https://hdl.handle.net/11511/22861

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Fatigue and static behavior of curved composite laminates Taşdemir, Burcu; Çöker, Demirkan; Department of Aerospace Engineering (2018) By virtue of the fact that curved composite laminates which are utilized as load carrying subcomponents in aircraft and wind turbine structures are subjected to cyclic loading during their operating time, it is crucial to understand fatigue failure mechanisms at least as much as static failure mechanisms. With the intention of understanding fatigue failure mechanisms and thus improving fatigue life of structures, these curved laminates are investigated experimentally under static and fatigue loadings. The f...
Progressive failure analysis of composite shells Olcay, Yasemin; Darendeliler, Haluk; Department of Mechanical Engineering (2012) 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 ...
Fatigue and fracture analysis of helicopter fuselage structures Özcan, Rıza; Dağ, Serkan; Department of Mechanical Engineering (2013) In this study a methodology is developed for the fatigue and fracture analysis of helicopter fuselage structures, which are considered as the stiffened panels. The damage tolerance behavior of the stiffened panels multiaxially loaded is investigated by implementing virtual crack closure technique (VCCT). Validation of VCCT is done through comparison between numerical analysis and the studies from literature, which consists of stiffened panels uniaxially loaded and the panel with an inclined crack. A program...
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 ...
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

O. Doğan, “Failure analysis of advanced composites under impact by cohesive zone method,” M.S. - Master of Science, Middle East Technical University, 2013.