A contribution to validation of SPH new features

Since 1998, the Smoothed Particle Hydrodynamics (SPH) method has been developed by LSTC in LS-DYNA®. This method is called a meshfree method because traditional finite elements are replaced by particles which are not physically connected but mathematically linked. It is an alternative to the classical Lagrangian Finite Elements method and is used to simulate problems where materials are submitted to hydrodynamic deformation modes, such as high velocity impacts. In order to improve the capabilities of SPH in LS-DYNA, LSTC recently developed several new functionalities available in the latest versions of LS-DYNA. The first new feature is the possibility to choose a Lagrangian kernel for SPH particles, which means there are always the same neighbors for one SPH node (more stability in tension). The second option is Hybrid SPH / Solid elements, designed to couple the benefits of both SPH and Lagrangian finite elements. With these new Hybrid elements, it is now possible to switch from SPH to solid elements using certain criteria and to realize a better transition between SPH and finite elements areas (no more tied contacts needed). This paper presents the DynaS+ contribution to the test and the validation of these new SPH options. Simple test cases and more complicated cases representative of industrial problems have been performed to assess the behavior and the interest of these new features. All tests have been conducted using LS-DYNA V970 R6.0.0 released in 2012. A comparison with older modeling ways will show the benefits they already bring, and the ones they will bring in the future, when their development will be completed.