A numerical model based on ALE formulation to predict crack propagation in sandwich structures

Abstract

A numerical model to predict crack propagation phenomena in sandwich structures is proposed. The model incorporates shear deformable beams to simulate high performance external skins and a 2D elastic domain to model the internal core. Crack propagation is predicted in both core and external skin-to-core interfaces by means of a numerical strategy based on an Arbitrary Lagrangian-Eulerian (ALE) formulation. Debonding phenomena are simulated by weak based connections, in which moving interfacial elements with damage constitutive laws are able to reproduce the crack evolution. Crack growth in the core is analyzed through a moving mesh approach, where a proper fracture criterion and mesh refitting procedure are introduced to predict crack tip front direction and displacement. The moving mesh technique, combined with a multilayer formulation, ensures a significant reduction of the computational costs. The accuracy of the proposed approach is verified through comparisons with experimental and numerical results. Simulations in a dynamic framework are developed to identify the influence of inertial effects on debonding phenomena arising when different core typologies are employed. Crack propagation in the core of sandwich structures is also analyzed on the basis of fracture parameters experimentally determined on commercially available foams.

Low velocity failure and integrity assessment of foam core sandwich panels

“…Cohesive models for sandwich core/skin interfaces were calibrated by means of comparisons with numerical and experimental data for mode I and mode II configurations. They also studied, [25], the influence of inertial effects on debonding phenomena and crack propagation in different core typologies of sandwich structures based on fracture parameters determined experimentally on commercially available foams. Park et al [26] investigated the force-time history curves of impacted sandwich structures and concluded that the damage resistance appears to be dependent on both the facesheet materials and core thickness: the lower the stiffness becomes, the greater the core thickness affects the impact resistance.…”

Numerical modeling based on moving mesh method to simulate fast crack propagation

“…Once that the predicted crack propagation angle is larger than the tolerance value, a re-meshing procedure is required. This procedure, extensively described in a previous authors' work developed in static framework [27], is made by proper script files implemented in a MATLAB® environment, which manages the numerical procedure. Fig.…”

A Numerical-Geometrical Methodology to Represent Out-of-Plane Mechanisms of Unreinforced Masonry Structures by Using Pushover Analysis

“…In the present work, the evaluation of the load carrying capacity is performed by a mass proportional force distribution. As known, by using implicit time integration schemes [22,23], the softening behavior, which is typically expected by the CDP, is hardly reproducible, since non-convergent behaviors of the solution might have happened. For these reasons, several attempts where an explicit time integration scheme to solve highly nonlinear systems under quasistatic or dynamic loads condition have been proposed in [24][25][26].…”