Shear-lag simulation of the progress of interfacial debonding in unidirectional composites

1999 ◽  
Vol 59 (1) ◽  
pp. 77-88 ◽  
Author(s):  
Shojiro Ochiai ◽  
Masaki Hojo ◽  
Tadanobu Inoue
Keyword(s):  
Interfacial Debonding ◽  
Shear Lag ◽  
Unidirectional Composites

Investigation of Damage in Unidirectional Ceramic Matrix Composites Using a Cohesive-Shear-Lag Model

2001 ◽  
Author(s):  
B. Yang ◽  
S. Mall
Keyword(s):  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Interfacial Debonding ◽  
Matrix Composites ◽  
Fiber Reinforced ◽  
Shear Lag ◽  
Stress Strain ◽  
Unidirectional Fiber ◽  
Shear Lag Model ◽  
Lag Model

Abstract The present study develops a cohesive-shear-lag model to analyze the cycling stress-strain behavior of unidirectional fiber-reinforced ceramic matrix composites. The model, as a modification to a classical shear-lag model, takes into account matrix cracking, partial interfacial debonding, and partial breakage of fibers. The statistical nature of partial breakage of fibers is modeled by using a cohesive force law. The validity of the model is demonstrated by investigating stress-strain hysteresis loops of a unidirectional fiber-reinforced ceramic-glass matrix composite, SiC/1723. This example demonstrates the capability of the proposed model to characterize damage and deformation mechanisms of ceramic matrix composites under tension-tension cycling loading. The dominant progressive damage mechanism with cycling in this case is shown to be accumulation of fibers breakage, accompanied by increase in interfacial debonding and smoothening of frictional debonded interface.

Numerical analysis and investigation of short- and long-term behavior of unidirectional composites

2017 ◽  
Vol 52 (5) ◽  
pp. 659-678
Author(s):  
Elias Dib ◽  
Jean François Caron ◽  
Wassim Raphael ◽  
Ioannis Stefanou ◽  
Fouad Kaddah
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Fiber Strength ◽  
Fiber Type ◽  
Glass Fibers ◽  
Shear Lag ◽  
Unidirectional Composites ◽  
Long Term Behavior ◽  
Shear Lag Theory

This study gives a detailed analysis on estimating the ultimate tensile strength of unidirectional fiber reinforced composites and its creep behavior under sustained tension load. We develop two different micromechanical models that allow us to estimate the longitudinal tensile strength and the evolution with time of fiber and matrix stresses around arbitrary array of fiber breaks. The first model is based on the shear-lag theory while the second one is developed using the software Abaqus. The comparison of the above models allowed to validate the fundamental assumptions of the shear-lag theory (first model) as well as several numerical issues related to time integration and spatial discretization. The Monte–Carlo method was used in order to account for the stochastic fiber strength and its impact on the ultimate tensile strength (short-term) and creep (long-term behavior) of unidirectional composites. Finally, a parametric investigation on the fiber type and the load level on the long-term behavior of unidirectional composites was performed showing an accelerating creep effect for fibers of inferior quality such as glass fibers compared to carbon fibers.

Evaluation of the Interfacial Properties in Polymer Matrix Composite: Experiments and Elasto-Plastic Shear-Lag Analysis

2007 ◽  
Vol 340-341 ◽  
pp. 167-172
Author(s):  
Souta Kimura ◽  
Jun Koyanagi ◽  
Takayuki Hama ◽  
Hiroyuki Kawada
Keyword(s):  
Carbon Fiber ◽  
Stress Distribution ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Interfacial Energy ◽  
Interfacial Debonding ◽  
Plastic Shear ◽  
Fiber Reinforced ◽  
Shear Lag

An energy-based analysis has been developed to evaluate interfacial adhesion between fiber and matrix in a single fiber composite over the years. However, the value of the energy-based parameter, e.g. an energy release rate, depends on a stress distribution predicted by a model employed. In the case of carbon fiber-reinforced plastics (CFRP), laser Raman spectroscopy (LRS) is significantly effective to validate the stress distribution predicted. The fragmentation tests with a model of carbon fiber-reinforced epoxy composite are performed, and LRS is used to detect a distribution of the fiber axial strain. An elasto-plastic shear-lag analysis methodology is employed, and a stress distribution is predicted under various approximations of s-s curve of the matrix resin and compared with the experimental results. Our recent energy-balance method, including an energy dissipation induced by plastic deformation around an interfacial debonding tip, is used to calculate an energy release rate to initiate an interfacial debonding (interfacial energy). An effect of the difference between the approximations on the value of the interfacial energy is discussed.

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