Modeling fragmentation with new high order finite element technology and node splitting

Abstract

Abstract. The modeling of fragmentation has historically been linked to the weapons industry where the main goal is to optimize a bomb or to design effective blast shields. Numerical modeling of fragmentation from dynamic loading has traditionally been modeled by legacy finite element solvers that rely on element erosion to model material failure. However this method results in the removal of too much material. This is not realistic as retaining the mass of the structure is critical to modeling the event correctly. We propose a new approach implemented in the IMPETUS AFEA SOLVER R based on the following: New High Order Finite Elements that can easily deal with very large deformations; Stochastic distribution of initial damage that allows for a non homogeneous distribution of fragments; and a Node Splitting Algorithm that allows for material fracture without element erosion that is mesh independent. The approach is evaluated for various materials and scenarios: -Titanium ring electromagnetic compression; Hard steel Taylor bar impact, Fused silica Taylor bar impact, Steel cylinder explosion, The results obtained from the simulations are representative of the failure mechanisms observed experimentally. The main benefit of this approach is good energy conservation (no loss of mass) and numerical robustness even in complex situations.

The research of destruction of functionally-graded materials subjected to impact loading

“…The algorithm of erosion elements, algorithm of splitting nodes, and algorithm for constructing the free surface were implemented to overcome the problem of the elements overlapping under large deformation. A similar approach to modeling the perforation problems developed in the work [6]. However, in the present approach, several ways of splitting nodes are possible.…”

Investigation of the behaviour of functionally graded materials under impact loads

“…According to the terminology [6], the numerical method contains a new way for isolating the surfaces of discontinuity of materials. A similar approach to modeling the perforation tasks developed in the work [7]. However, in the present approach, several ways of splitting nodes are possible.…”

Pipeline Fracture due to Compression-Tension Loading Caused by Foreign Object Impact

“…The energy balance was typically of the order of 3% kinetic energy or less for these simulations, which is acceptable. When the damage parameter D attains unity in one of the 64 Gauss points in each element, the material fails by a node-splitting algorithm [22]. The exterior node closest to the integration point is split, and new element faces are created so that the crack plane is orthogonal to the maximum principal stress.…”