You might want to avoid abbreviations unless you plan to define them. Of your four abbreviations, I recognize one.

SPH Errors in LS-DYNA SPH (Smmoothed Particle Hydrodynamics) errors in an LS-DYNA composite impact simulation involving a rigid impactor typically stem from solver conflicts related to how rigid bodies interact with deformable elements. The primary causes include: Incompatible Contact Definitions: Default contact algorithms (e.g., AUTOMATIC_SURFACE_TO_SURFACE) can struggle to robustly manage interactions between a purely mathematical rigid body and deformable composite shell or solid elements, leading to node-on-surface penetration errors that trigger the SPH solver. Rigid Body Formulation: The formulation of the MAT_RIGID material model can conflict with certain boundary conditions or interaction types, causing numerical instability. Material Model Conflicts: The abrupt interface between an infinitely stiff body and a deformable material can create solver-level issues that are misinterpreted as needing SPH intervention. Replacing the rigid body with a deformable body assigned a high-stiffness (high-modulus) material resolves the error because it uses a standard finite element formulation that interacts more predictably with contact algorithms, thus avoiding the specific solver conflicts associated with the MAT_RIGID definition. However, it is crucial to validate that the deformation of this pseudo-rigid impactor is negligible to ensure the simulation results remain physically accuratte.