Recently, trimmed Isogeometric B-Spline solid elements have been introduced in Ansys LS-DYNA ® nonlinear dynamics structural simulation software [1]. The numerical analysis methodology Isogeometric Analysis (IGA) dates to the paper by Hughes et al. [2] in 2005. While in standard Finite Element Analysis (FEA) polynomial basis functions are typically used for the discretization of the geometry and the unknown fields, IGA aims to use the same shape functions employed in the Computer Aided Design (CAD) environment for numerical analysis. This paper reviews the main ideas and concepts of the trimmed IGA B-spline solid finite elements in LS-DYNA and provides an update on the available capabilities. The current modeling workflow for these new element types will be first introduced. Modeling strategies for boundary conditions, contact and connections, and in-core refinement possibilities will be presented, and some recommendations and best practices will be discussed. The potential benefits of this new type of solid finite elements will be illustrated by two numerical examples. The paper closes with a summary and an outlook on future development activities.
With the changes in the global environment such as global warming, automobile OEMs and their affiliates have an urgent need to address carbon neutrality and resource circulation to reduce the environmental impact of their products and their corporate activities. Under such circumstances, as part of the effective use of materials, companies are considering the adoption of large aluminum diecast (ALDC) parts aimed at weight reduction through part integration, and enhancement of material recycling rates. Some OEMs have already introduced such parts to the market. Since prototyping and testing of large ALDC parts require enormous costs and time, it is important to be able to predict and evaluate the part performance through simulations. Crash calculations are no exception.
Isogeometric Analysis (IGA) has emerged as a next generation advancement in the field of Computer-Aided Engineering (CAE) and simulation thanks to its ability to utilize geometric representations native to Computer-Aided Design (CAD) models. Ansys LS-DYNA®’s proven capabilities for IGA have made it the premier solver for the technology. While the direct benefits for analysis are well documented, industrial adoption has been hampered by the difficulty in producing IGA-ready models from CAD data. Trimmed multi-patch IGA preprocessing approaches have seen advances at the industrial level but the desire for untrimmed body-fit unstructured splines has remained an unsolved approach in IGA preprocessing. In this paper, we discuss an IGA preprocessor for Ansys LS-DYNA® that not only produces untrimmed body-fit unstructured splines but does so in a process that is integrated directly into a CAD application.
Isogeometric Analysis (IGA) [1] is a Finite Element Analysis (FEA) technology that uses spline basis functions known from Computer Aided Design (CAD) to describe the geometry and the solution field. Employing such spline basis functions with higher order and higher continuity may yield several advantages such as an easier transition from CAD to analysis, a more accurate geometry description, smooth solution fields or a larger time step in explicit analysis. In fact, only the higher-continuity property of splines enables the concept of trimming (ubiquitous in CAD) to be used in explicit analysis with a feasible time step size [2].
Updates on trimmed IGA B-Spline Solids