delamination

We have an open position as a PhD student in the area of fracture mechanics of fibre composites. The focus of the position is to develop element test specimens, i.e., test specimens that are purposely-designed with the aim of checking the accuracy of model predictions of damage evolution (two or more damage types) in composite structures subjected to static and cyclic loading

Please find attached two recent papers on the use of high order B-splines/NURBS cohesive interface elements for an efficient modeling of delamination of composite laminates.  

model reduction, mesh burden reduction, mesh burden, mesh, multiscale fracture, polycrystals, delamination, surgical simulation http://orbilu.uni.lu/handle/10993/16404 http://orbilu.uni.lu/bitstream/10993/16404/2/20140422_HannoverGermany.m4v

Hi,

  I'm Praveen doing my Master of Technology Project. I wanted to know how to model delaminated composites in ANSYS. Whether to use Teflon layer as delamination between the plies or creating air gap between the plies? And also wanted to know how to use cohesive zone elements or interface elements to create delamination. Can anyone help me? I ve attached images for references. 

Hello all,

Last year when I started implementing interface elements to model material failure, I realized that the formulation is easy except how to generate a mesh with interface elements. I did a googling to search for such a free program. Amazingly, I did not find any although there are many researchers working on the fracture mechanics field.

So, I wrote a small object-oriented C++ program which reads a FE mesh, duplicates nodes and insert interface elements where asked. The program is able to

(1) insert 1D/2D interface elements everywhere in a FE mesh

The deadline for submitting abstracts has now been extended to 15 November. To submit, go to http://www.tc4pca.elsevier.com/abstractsubmission.asp

The Graduate School MUSIC (Multiscale Methods for Interface Coupling) invites to its first Summer School on Multiscale and Multiphysics Modelling of Interfaces at Leibniz Universitaet Hannover, Germany, from 15 to 17 September 2010.

Hi,
I am working on effects of Blast Loading in sandwich composites using Abaqus. I want to incorporate Cohesive behaviour at the interface of the two materials in the sandwich composite structure i am analysing.

H. Mei, Y. Pang, and R. Huang, International Journal of Fracture 148, 331-342 (2007).

Following a previous effort published in MRS Proceedings, we wrote a journal article of the same title, with more numerical results. While the main conclusions stay the same, a few subtle points are noted in this paper.

In flip-chip package, the mismatch of thermal expansion coefficients between the silicon die and packaging substrate induces concentrated stress field around the edges and corners of silicon die during assembly, testing and services. The concentrated stresses result in delamination on many interfaces on several levels of structures, in various length scales from tens of nanometers to hundreds of micrometers. A major challenge to model flip-chip packages is the huge variation of length scales, the complexity of microstructures, and diverse materials properties. In this paper, we simplify the structure to be silicon/substrate with wedge configuration, and neglect the small local features of integrated circuits. This macroscopic analysis on package level is generic with whatever small local features, as long as the physical processes of interest occur in the region where the concentrated stress field due to chip-packaging interaction dominates. Because it is the same driving force that motivates all of the flaws. Therefore, the different interface cracks with same size and same orientation but on different interfaces should have similar energy release rates provided that the cracks are much smaller than the macroscopic length. We calculate the energy release rate and the mode angle of crack on the chip-package interface based on the asymptotic linear elastic stress field. In a large range of crack length, the asymptotic solution agrees with finite element calculation very well. We discuss the simplified model and results in context of real applications. In addition, we find that the relation of energy release rate G and crack length a is not power-law since local mode mixity is dependent of crack length a. Therefore, the curve of G~a can be wavy and hardly goes to zero even if crack length a goes to atomically small. The local mode mixity plays an important role in crack behavior.