On Reliable Finite Element Methods for Extreme Loading Conditions

Abstract

Abstract. In this paper we focus on the analysis of solids and structures when these are subjected to extreme conditions of loading resulting in large deformations and possibly failure. The analysis should be conducted with finite element methods that are as reliable as possible and effective. The requirement of reliability is important in any finite element analysis but is particularly important in simulations involving extreme loadings since physical test data are frequently not available, or only available for some similar conditions. To then reach a high level of confidence in the computed solutions requires that reliable finite element procedures be used.While in this paper a large field of analysis is covered, the presentation is narrow because it only focuses on our research results, mostly published in the last decade (since 1995), and only on some of our contributions. Hence, this paper is not written to fully survey the field.

Dynamics of spatial flexible multibody systems with clearance and lubricated spherical joints

“…Nevertheless, the Bathe's scheme is more robust, stable and quite interesting for long time simulations since larger time steps can be used. The interested reader in the details of Bathe's scheme is referred to references [64,66,67]. However, when a multibody system includes joints with clearance, small time steps have to be used, and special attention should be paid to detect the precise instant of contact [68].…”

An implicit discontinuous Galerkin finite element framework for modeling fracture failure of ductile materials undergoing finite plastic deformation

“…First, we have formulated DG methods for crack propagation in finite plastic media in implicit computational frameworks rather than in explicit frameworks. The reliability of explicit and implicit finite element methods has been extensively discussed in the literature . In summary, while explicit dynamic simulations are widely used to evaluate high‐speed impact problems, quasi‐static and low‐speed problems are more appropriately and more effectively simulated using implicit dynamic or static solution techniques that are traditionally favored for solid mechanics problems.…”

“…The reliability of explicit and implicit finite element methods has been extensively discussed in the literature. [49][50][51][52] In summary, while explicit dynamic simulations are widely used to evaluate high-speed impact problems, quasi-static and low-speed problems are more appropriately and more effectively simulated using implicit dynamic or static solution techniques 49 that are traditionally favored for solid mechanics problems. Furthermore, the fracture failure of ductile materials often involves large plastic deformation.…”

Maintaining a grasp on reality – Is our validation and design effort focused in the same direction?

“…3 Additionally, it can be difficult and in some cases impossible, for example, extreme environment applications to faithfully represent in-service conditions in a structural test programme. 4,5 The simulation of structural failure by numerical methods has long been possible, 6 and with the appropriate and disciplined use of simulation software, the physical behaviour of many scenarios may be accurately modelled. However, potential unknowns or variability in the physical materials and the environment in which they are manufactured and operate suggests that computational methods cannot replace physical testing completely.…”