The project involves nonlinear finite element modeling using the commercial finite element code ABAQUS. The project involves using a newly developed user material subroutine and can ether include application of the model on specific problems or improvement of the implemented model.

Purpose

For high strength carbon fiber reinforced polymers, the design criteria are often specified by the compression strength of the composite component. This is due to the fact that the compression strength of unidirectional composites is as low as 50 to 60 percent of the tensile strength. One important compressive failure mode in composite is kink-band formation which for a great deal is governed by the waviness of the fibers and the yielding properties of the matrix material. Therefore, in order to make proper simulation of the failure modes in composites, it is necessary to take these effects into account. One approach is to model the actually fiber/matrix system using a micromechanical based finite element model. For realistic composite structures with large number of fibers, approaches which will result in extremely large numerical models including a great deal of unwanted details. An alternative is to base the simulation on a smeared out composite model where the nonlinear properties of the constituents are taken into account. This alternative will be used in the proposed project.

Description

Based on a finite element implementation of a non-linear smeared out model suited for compressive deformation of fiber reinforced polymers, compressive failure behavior will be simulated using the commercial finite element program Abaqus. The model can e.g. be used to investigate the interaction between overall structural buckling, sub-structural delamination and local kink-band formation in realistic fiber composite components.



Kink-band prediction in a block of material under compression using the smeared out composite model in a plan strain version.

Qualifications

Mechanics of materials and continuum mechanics, finite element modeling. Knowledge on plasticity theories, non-linear finite element modeling and on using ABAQUS is an advantage but is not essential.

Project form

Thesis Final year project

Subjects

Materials

Duration