Investigation of the effect of resin behavior on long fiber composites in shear for the prediction of compressive strength
Topic(s) : Material and Structural Behavior - Simulation & Testing
Co-authors :
Fabing EMMANUEL (FRANCE), Pierre-Yves MECHIN (FRANCE), Vincent KERYVIN (FRANCE)Abstract :
Carbon Fibers Reinforced Polymers are widely used for their excellent mechanical properties (both stiffness & strength). Those materials are characterized with an experimental program to understand the mechanisms involved alongside the different failure modes. This highly depends on the manufacturing process.
The compressive failure mechanism is a first order challenge complex to capture. Compressive strength is a structural property which requires material parameters from the different scales, from constituents to global stacking sequence. The compressive strength relies on the micro buckling of the fibres contained by the resin system used and the neighboring plies to the Uni-directional plies (UD). A correlation between the global compressive load applied and the local mechanism of the UD corresponding to a pure shearing of the UD was established [1]. In addition, the contribution of the neighboring plies or the deformation gradient (axial vs. flexural loading) was widely covered [2]. The micro-buckling contribution is the largest one driving the compressive strength (more than 80% of the measured strength). The shear behavior of the UD is measured from tension test on ±45° laminate or computed from multiscale simulation thanks to fibres and resin behaviors [3]. Constituent’s properties are characterized from neat resin test. Orthotropic Properties of the fibres are retrieved from both datasheet and papers which attempted to measure the properties from complex indirect experiments [4]. Predictions of the shear response of the UD and comparison to experiments has been successfully performed by several authors [3], [5]. The predictions were proposed considering a hexagonal Representative Volume Element (RVE) for the microstructure. Hexagonal is used for multiscale computation, same if difference were observed between the microstructures (Hexagonal and Random) [6].
This study proposes to quantify the effect of the speed rate on the resin performance. The behaviour of the resin is modeled with a Ramberg-Osgood model (non-linear elastic). The virtual computation of the shear of the UD is performed and compare to the experiments done on ±45° coupons with different rates. Accordingly, the effect on the compressive strength is estimated. The effect of the speed rate on the compressive strength provides an opportunity to estimate fatigue prediction thanks to time-temperature superposition principle. In addition, the effect of the void content on the resin system performance to compare to the experiments on tension tests on ±45° and axial compressive strengths measurements performed on M21 resin and IM7 fibres with different void content [7]. A porous media RVE is set thanks to 3DEXPERIENCE Platform to quantify the effect of the void on the resin behaviour. The ability to faithfully predict the behavior of the UD opens the possibility of exploring a wide range of fiber/resin/process configurations through virtual testing.
The compressive failure mechanism is a first order challenge complex to capture. Compressive strength is a structural property which requires material parameters from the different scales, from constituents to global stacking sequence. The compressive strength relies on the micro buckling of the fibres contained by the resin system used and the neighboring plies to the Uni-directional plies (UD). A correlation between the global compressive load applied and the local mechanism of the UD corresponding to a pure shearing of the UD was established [1]. In addition, the contribution of the neighboring plies or the deformation gradient (axial vs. flexural loading) was widely covered [2]. The micro-buckling contribution is the largest one driving the compressive strength (more than 80% of the measured strength). The shear behavior of the UD is measured from tension test on ±45° laminate or computed from multiscale simulation thanks to fibres and resin behaviors [3]. Constituent’s properties are characterized from neat resin test. Orthotropic Properties of the fibres are retrieved from both datasheet and papers which attempted to measure the properties from complex indirect experiments [4]. Predictions of the shear response of the UD and comparison to experiments has been successfully performed by several authors [3], [5]. The predictions were proposed considering a hexagonal Representative Volume Element (RVE) for the microstructure. Hexagonal is used for multiscale computation, same if difference were observed between the microstructures (Hexagonal and Random) [6].
This study proposes to quantify the effect of the speed rate on the resin performance. The behaviour of the resin is modeled with a Ramberg-Osgood model (non-linear elastic). The virtual computation of the shear of the UD is performed and compare to the experiments done on ±45° coupons with different rates. Accordingly, the effect on the compressive strength is estimated. The effect of the speed rate on the compressive strength provides an opportunity to estimate fatigue prediction thanks to time-temperature superposition principle. In addition, the effect of the void content on the resin system performance to compare to the experiments on tension tests on ±45° and axial compressive strengths measurements performed on M21 resin and IM7 fibres with different void content [7]. A porous media RVE is set thanks to 3DEXPERIENCE Platform to quantify the effect of the void on the resin behaviour. The ability to faithfully predict the behavior of the UD opens the possibility of exploring a wide range of fiber/resin/process configurations through virtual testing.