Trimmed IGA B-Spline Solids vs. Standard Tetrahedra Finite Elements

In 2005, Hughes et al. [1] introduced isogeometric analysis (IGA). As opposed to standard Lagrange polynomial-based finite element analysis (FEA), IGA utilizes the same shape functions employed in computer-aided design (CAD) for numerical analysis. In the last decade, the development of IGA in LS-DYNA was mainly focused on thin-walled structures modelled as either structured trimmed or unstructured isogeometric shells. Currently, there is growing interest in the analysis of more complex engineering parts. This requires the use of accurate solid finite elements. It is well known however that rather poor computational performance can be achieved by invoking low-order solid elements. Recently, the potential benefits of volumetric B-spline finite elements have been successfully demonstrated by Meßmer et al. [2], [3]. This led to an increased customer interest and thus to the development of trimmed isogeometric solids in LS-DYNA. This paper provides an overview of basic concepts and current capabilities of trimmed isogeometric solids in LS-DYNA.