Timothy Shelton

Validation of Grid-Based Hex Meshes with Computational Solid Mechanics

Grid-based methods for generating all-hex meshes show tremendous promise in automating and speeding up turnaround for computational simulations for solid mechanics. Recognizing some of its inherent weaknesses, there has been hesitancy in accepting this technology as a viable option for critical FEA. This study attempts to compare meshes generated with traditional manual pave-and-sweep technologies with those generated with an automatic overlay grid method. We use a simple torsion pin analysis to understand both linear-elastic and non-linear elastic-plastic responses with grid based meshes. This study demonstrates that in the cases tested, equivalent or superior results were achieved with grid-based meshes when compared to pave-and-sweep meshes.

An Exploration of Accuracy and Convergence of the Degenerate Uniform Strain Hexahedral Element: A Solution to the Unmeshed Void in an All-Hexahedral Mesh

The uniform strain hexahedral element mesh has long been a work horse for getting accurate and convergent answers in high deformation solid mechanics analyses. Obtaining an all-hexahedral mesh can be a difficult and time consuming process thus limiting the element’s use in design phase computations. Unconstrained paving and plastering offers a technique to get an all-hexahedral mesh automatically but still can leave un-meshable voids [1]. While degenerated forms of the uniform strain hexahedral element such as the wedge have been used sparingly, they have garnered limited general acceptance. We present a more exhaustive numerical exploration of the degenerated hexes with the hope of encouraging their use to resolve the un-meshable voids. The results of patch tests are used to numerically demonstrate linear completeness of the degenerate elements. A manufactured solution analysis is then used to show optimal convergence rates for meshes containing degenerate elements. Additionally, applications to a torsion rod and high velocity impact are used to highlight the accuracy and applicability of degenerates for solving more complex problems.Copyright

Adagio 4.20 User’s Guide

Adagio is a Lagrangian, three-dimensional, implicit code for the analysis of solids and structures. It uses a multi-level iterative solver, which enables it to solve problems with large deformations, nonlinear material behavior, and contact. It also has a versatile library of continuum and structural elements, and an extensive library of material models. Adagio is written for parallel computing environments, and its solvers allow for scalable solutions of very large problems. Adagio uses the SIERRA Framework, which allows for coupling with other SIERRA mechanics codes. This document describes the functionality and input structure for Adagio.