Progressive interlaminar failure analysis in composite missile structures

2016
Bartan Kumbasar, Büşra
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 tests of the missile wing are performed, a simpler structure is modelled and tested to investigate the delamination behavior in the twill composite. In this study, simpler structure is selected as the open-hole plate. To initiate delamination, a thin film is inserted in a known location the composite plate in order to provoke delamination and examine the delamination progression behavior at different load levels. After the prediction of delamination initiation and propagation behavior by finite element analysis, open hole tensile test specimens are manufactured by the same twill composite which is used in the missile. Intact (OHT) and delaminated (DOHT) open hole tensile specimens are tested in tensile loading and comparisons are made with the experimental results. The load - displacement curve and load-strain curves obtained for the OHT specimens and DOHT specimens by the finite element analysis and the tests showed relatively good agreement. It is also shown that the increment of delamination areas measured for the DOHT specimens by the C-Scan differed from the finite element solution by %17. For the composite missile wings, similar analysis and test method is followed as the open-hole specimens but in bending load condition. It is shown that the increment of delamination areas measured for DWs by the C-Scan differed from the finite element solution by %7.3. The preliminary analysis performed on a real structure such as a composite missile wing showed that with the cohesive zone modeling, the progression of delamination can be predicted fairly accurately.

Suggestions

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 ...
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 ...
Experimental and computational study of the damage process in CFRP composite beams under low-velocity impact
Topac, O. Tanay; Gözlüklü, Burak; Gürses, Ercan; Çöker, Demirkan (2017-01-01)
Damage process in composites subjected to low-velocity impact is investigated both experimentally and numerically. Drop-weight impact experiments are carried out, in which a model unidirectional [0(5)/90(3)](s) CFRP laminate beam is impacted by a cylindrical head creating an almost uniform two-dimensional loading condition. Initiation and progression of damage, consisting of matrix cracks and delamination, are visualized in real-time via ultra-high-speed camera at rates up to 60,000 fps and the sequence of ...
Failure analysis of tapered composite structures under tensile loading
Çelik, Ozan; Parnas, Kemal Levend; Department of Mechanical Engineering (2016)
A three dimensional finite element modeling approach is used to evaluate the effects of preliminary design variables on the performance of tapered composite laminates under tensile loading. Hashin failure criteria combined with a progressive failure algorithm is used for in-plane failure mechanisms and cohesive zone method is used for out-of-plane failures. The modeling approach is validated by a comparison with experimental results from literature. The validated model is used to examine various design vari...
Experimental investigation of particle filtration in compression resin transfer molding of advanced composites
Aydil Dalkıran, Tuğçe; Erdal Erdoğmuş, Merve; Department of Mechanical Engineering (2014)
With the inclusion of particle fillers in advanced continuous fiber reinforced composites, issues such as impregnation with increased viscosity of the injected resin leading to high process pressures and possible nonhomogeneous/directional composite properties due to filtering of filler particles necessitate the study of the relations between processing parameters and the resulting particle distributions. In this study, the particle-resin interaction during compression resin transfer molding (CRTM) and resi...
Citation Formats
B. Bartan Kumbasar, “Progressive interlaminar failure analysis in composite missile structures,” M.S. - Master of Science, Middle East Technical University, 2016.