Experimental and numerical investigation of damage process in composite laminates under low-velocity impact

Topaç, Ömer Tanay
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 camera at rates up to 60,000 fps and the sequence of failure events are captured. Evolution of dynamic strain fields is then quantified by a Digital Image Correlation (DIC) analysis and the resulting final failure patterns are characterized by a digital microscope. In the computational part, 3D finite element analysis is performed using ABAQUS/Explicit to simulate the experiments. Intraply matrix damage is modeled using a Continuum Damage Mechanics (CDM) based composite failure theory with LaRC04 initiation criterion and implemented via a user-written VUMAT subroutine. Delamination is modeled using cohesive interface elements introduced between 0°/90° interfaces. Damage initiation time, location and the interaction of failure modes and symmetry are compared with the experiments. The sequence of dynamic matrix cracking followed by dynamic delamination is observed for the first time. A good agreement between experimental and numerical results is achieved.


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One of the widely used geometrically complex parts in advanced commercial aircraft is L-shaped composite laminates in which mixed-mode delamination failure is reported. Dynamic delamination under quasi-static loading is studied using explicit finite element method in conjunction with Cohesive Zone Modeling (CZM). A 4-noded interface element working with Bilinear (BL), Xu-Needleman (XN) and ratedependent bilinear (RD) CZMs are implemented in ABAQUS/Explicit. The interface elements are validated with benchmar...
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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...
Citation Formats
Ö. T. Topaç, “Experimental and numerical investigation of damage process in composite laminates under low-velocity impact,” M.S. - Master of Science, Middle East Technical University, 2016.