CTH reference manual : composite capability and technologies.

The composite material research and development performed over the last year has greatly enhanced the capabilities of CTH for non-isotropic materials. The enhancements provide the users and developers with greatly enhanced capabilities to address non-isotropic materials and their constitutive model development. The enhancements to CTH are intended to address various composite material applications such as armor systems, rocket motor cases, etc. A new method for inserting non-isotropic materials was developed using Diatom capabilities. This new insertion method makes it possible to add a layering capability to a shock physics hydrocode. This allows users to explicitly model each lamina of a composite without the overhead of modeling each lamina as a separate material to represent a laminate composite. This capability is designed for computational speed and modeling efficiency when studying composite material applications. In addition, the layering capability also allows a user to model interlaminar mechanisms. Finally, non-isotropic coupling methods have been investigated. The coupling methods are specific to shock physics where the Equation of State (EOS) is used with a nonisotropic constitutive model. This capability elastically corrects the EOS pressure (typically isotropic) for deviatoric pressure coupling for non-isotropic materials