Local damage in a 5-harness satin weave composite under static tension, part II: meso-FE modelling

International audienceThis study forms the second part of a paper on the local damage analysis in a thermo-plastic 5-harness satin weave composite under uni-axial static tensile load. The experimental observations of Part I are confronted with the meso-FE simulations. Part II describes the following steps regarding the unit cell meso-FE modeling starting from: 1) Construction of the unit cell geometrical model; 2) Estimation of the homogenized elastic constants of the unit cell using different boundary conditions; 3) Evaluation of the local stress and damage behavior of the unit cell using meso-FE simulations. The aim of the numerical analysis is to investigate the dependency of local ply stress and damage profiles on the adjacent layers of the laminate

Strain rate effect on the mechanical behaviour of a textile reinforced cement composite

The static tensile behaviour of Textile Reinforced Cement Composites is known and can be modeled adequately. However, using these static material properties under dynamic loadings such as impact and seismic loadings, can cause over- or underestimation of the material due to effects of strain rate. This work focuses on the strain rate dependency of a specific textile reinforced cement composite under tensile loadings at strain rates equivalent to quasi static applications towards low velocity impacts. It was found that the main damage mechanisms of this material stay the same. However cracking of the cement matrix is delayed to higher stress levels

A new meso-scale modelling of static and fatigue damage in woven composite materials with finite element method

Aim of this work is to evaluate the fatigue damage in textile composites on meso-scale level. Pre-damage properties, damage thresholds and damage propagation of unit cell (UC) are calculated and validated by experiments. Quasi-static damage algorithm is further used to model the cycles of the fatigue loading. Model output is the computed SN curve of textile composites

A progressive damage model of textile composites on meso-scale using finite element method: static damage analysis

A meso-scale finite element model for static damage in textile composites was established. The impregnated yarn is taken as homogeneous and transverse isotropic material, whose mechanical properties are calculated using Chamis' equations. The damage modes are determined by using the Tsai-Wu criterion and additional criteria. The Murakami damage tensor is used to calculate the post-damage stiffness matrix. The model has been validated using plain weave and twill weave carbon-epoxy composites. The initiation of inter-fiber matrix cracks and fiber rupture were analyzed using this meso-FE model

Local damage in a 5-harness satin weave composite under static tension, part I: experimental analysis

International audienceThis paper presents an experimental damage analysis of a 5-harness satin weave carbon-PPS (PolyPhenylene Sulphide) composite under uni-axial static tensile load. In order to understand the local damage behaviour, tensile tests were performed and accompanied by acoustic emission (AE) and microscopic analysis of the composite specimen. These tests enable us to detect the damage initiation stress as well as the damage initiation location in the composite. Microscopic observation of the tested composite laminates allowed the characterization of the sequence of intra-yarn transverse damage (perpendicular to the load direction) occurrence at different locations in the laminate, starting from crack initiation to the final failure of the composite

Large-scale blast loading of a composite tube array for protection of civil engineering structures

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On the nonlinear evolution of the Poisson’s ratio under quasi-static loading for a carbon fabricreinforced thermoplastic, Part I:

a b s t r a c t When observing or describing the damage state in a composite material, often only Young's modulus or residual deformation are considered. Generally, however, the Poisson's ratio is more sensitive to damage than those properties. Rather than observing the Poisson's ratio as function of crack density, the evolution of the Poisson's ratio as function of the longitudinal strain was studied in part I of this research, where a peculiar shape of the evolution was observed and proven to be entirely due to the material itself, rather than the sensors used for the strain measurement. In this article, a theoretical explanation for the peculiar evolution of the Poisson's ratio as function of the longitudinal strain is presented. Based on this explanation, extra experiments were conducted for validation purposes. The material used for this study is a carbon fabric-reinforced PPS