Ply scale modelling of CFRP/GFRP laminates under quasi-static, fatigue loading and environmental conditions
Topic(s) : Material and Structural Behavior - Simulation & Testing
Co-authors :
Julie CURBELIÉ (FRANCE), Jean-Christophe WAHL (FRANCE), Christophe BOIS (FRANCE)Abstract :
Ply scale modelling of CFRP/GFRP laminates under quasi-static, fatigue loading and environmental conditions
Context
Environmental concerns lead manufacturers to use more and more composite material and also to think about their end of life and how to recycle them in order to limit their product’s carbon footprint. In this context, thermoplastic matrices and their recycling abilities are an opportunity. However, composite material are sometimes used in structural ways within more or less severe environments. Current thermoplastic matrices are sensitive to temperature: the very significant variations of all the material’s properties near the glass transition Tg strongly impact its mechanical properties.
Our research team works from years on the sizing of composites structures, especially under thermomechanical fatigue loading. A specific model defined at the ply scale, has been developed and identified for Glass/Epoxy [1] and Glass/PMMA [2,3] composites. In this paper, experimental results for a carbon/thermoplastic composite material, made from tapes with the AFP process, and modelling results are presented.
Study
The aim is to model the composite behaviour under static, fatigue, creep and thermal loading. The experimental results were used to identify the parameters of the ply scale model, to find out evolution laws to model the influence of the temperature and the creep behaviour and to validate the model.
The damage model we chose was first developed by Ladevèze et al. [4] in 1992 and was since completed by several studies in order to take into account fatigue loadings and several types of fibre reinforcement. It is a ply-scale modelling that consider homogeneous orthotropic ply and use the laminate theory. The model is based on thermodynamical forces used to determine the evolution of the three damage variables considering a cumulative influence of fatigue and monotonic loadings.
Figure 1 : Comparison of model predictions and experimental data for a tensile loading applied to BXS [(±45)2]s with Vf = 50.5%
The evolution law’s parameters can be identified with eight different tests. This identification was made at several temperature in the range (-20°C-60°C) to evaluate the influence of the temperature on the fatigue, creep and quasi-static behaviour. Moreover, water ageing and DMA tests were performed to highlight the influence of moisture environment on composite lifespan.
Figure 2 : Observation at 2,4% longitudinal strain of a sample BXS [(0°/90°)2]s tested with a quasi-static tensile loading with (a) at 15°C many transverse cracking et (b) at 40°C, no transverse cracking
Context
Environmental concerns lead manufacturers to use more and more composite material and also to think about their end of life and how to recycle them in order to limit their product’s carbon footprint. In this context, thermoplastic matrices and their recycling abilities are an opportunity. However, composite material are sometimes used in structural ways within more or less severe environments. Current thermoplastic matrices are sensitive to temperature: the very significant variations of all the material’s properties near the glass transition Tg strongly impact its mechanical properties.
Our research team works from years on the sizing of composites structures, especially under thermomechanical fatigue loading. A specific model defined at the ply scale, has been developed and identified for Glass/Epoxy [1] and Glass/PMMA [2,3] composites. In this paper, experimental results for a carbon/thermoplastic composite material, made from tapes with the AFP process, and modelling results are presented.
Study
The aim is to model the composite behaviour under static, fatigue, creep and thermal loading. The experimental results were used to identify the parameters of the ply scale model, to find out evolution laws to model the influence of the temperature and the creep behaviour and to validate the model.
The damage model we chose was first developed by Ladevèze et al. [4] in 1992 and was since completed by several studies in order to take into account fatigue loadings and several types of fibre reinforcement. It is a ply-scale modelling that consider homogeneous orthotropic ply and use the laminate theory. The model is based on thermodynamical forces used to determine the evolution of the three damage variables considering a cumulative influence of fatigue and monotonic loadings.
Figure 1 : Comparison of model predictions and experimental data for a tensile loading applied to BXS [(±45)2]s with Vf = 50.5%
The evolution law’s parameters can be identified with eight different tests. This identification was made at several temperature in the range (-20°C-60°C) to evaluate the influence of the temperature on the fatigue, creep and quasi-static behaviour. Moreover, water ageing and DMA tests were performed to highlight the influence of moisture environment on composite lifespan.
Figure 2 : Observation at 2,4% longitudinal strain of a sample BXS [(0°/90°)2]s tested with a quasi-static tensile loading with (a) at 15°C many transverse cracking et (b) at 40°C, no transverse cracking