66
4 Mechanical characterization on constituent level
material model is selected according to the characteristics known from the performed
tests and literature. These characteristics largely coincide with UD-composite materials,
which require orthotropic elasticity and brittle failure, while tensile and compressive
strength are given separately. Such material models are standard in commercial FE-solvers. However, the shear plasticity of fabric composites is generally not covered by these
UD-material models. In ABAQUS\Explicit this behavior can be modeled using a pre-compiled user subroutine (VUMAT)
1 , which is based on the continuum damage mechanics
model of Johnson [Joh01]. This VUMAT is described in more detail in Appendix A2.
Honeycomb bonded prepreg (HC)
Flat pressed prepreg (FP)
Figure 51 Comparison of HC pressed and flat pressed prepregs in terms of tensile properties
For comparison with the test results and for calibration of the material properties the
performed tests are remodeled in ABAQUS/Explicit using S4R elements and the aforementioned VUMAT subroutine. Due to the small specimen size, the test is modelled in
1 VUMAT for Fabric Reinforced Composites, since ABAQUS 6.8
1mm
1mm
4 Mechanical characterization on constituent level
material model is selected according to the characteristics known from the performed
tests and literature. These characteristics largely coincide with UD-composite materials,
which require orthotropic elasticity and brittle failure, while tensile and compressive
strength are given separately. Such material models are standard in commercial FE-solvers. However, the shear plasticity of fabric composites is generally not covered by these
UD-material models. In ABAQUS\Explicit this behavior can be modeled using a pre-compiled user subroutine (VUMAT)
1 , which is based on the continuum damage mechanics
model of Johnson [Joh01]. This VUMAT is described in more detail in Appendix A2.
Honeycomb bonded prepreg (HC)
Flat pressed prepreg (FP)
Figure 51 Comparison of HC pressed and flat pressed prepregs in terms of tensile properties
For comparison with the test results and for calibration of the material properties the
performed tests are remodeled in ABAQUS/Explicit using S4R elements and the aforementioned VUMAT subroutine. Due to the small specimen size, the test is modelled in
1 VUMAT for Fabric Reinforced Composites, since ABAQUS 6.8
1mm
1mm