Engineering Fracture Mechanics

Videos of Tests A and B

We developed a semi-analytical fibre bundle model to simulate the longitudinal tensile failure of large composite bundles of continuous fibres. The model uses shear-lag to calculate the stress recovery along broken fibres, and an efficient field superposition method to calculate the stress concentration on the intact fibres, which has been validated against analytical and FE results from the literature. The baseline version of the model uses static equilibrium stress states, and considers fibre failure driven by strength of materials (stress overload) as the only damage theory which can drive bundle failure. Like other models in the literature, the baseline model fails to capture the correct size effect (decreasing composite strength with bundle size) shown by experimental results. Two model variants have been developed which include dynamics stress concentrations (model DE) and a fracture mechanics (model FM) failure criterion respectively. To the knowledge of the authors, it is the first attempt in the literature to investigate these two effects in a fibre bundle model by direct simulation of large composite bundles.

The data include the results of CA and OL experiments on QSTE340TM steel, and the fatigue crack growth rate predicted by a proposed effective SIF fatctor and a proposed model.

Processed AE data from set of hydraulic fracture experiments on Barre granite. Raw waveforms are excluded for ease of upload/download.

The dataset contains a material routine (UMAT.f) and a user-defined hardening routine (UHARD.f) to be used in conjunction with FE-program ABAQUS. These subroutines enable to take into account gradient-enhanced damage. A special ductile damage model is implemented. Different examples (input-files) are given to conduct convergence studies (shear band specimen, plate-with-hole, double-notched tensile test). More information about usage is given in the short-documentation (Doc.pdf).

Figures 1 - 22 and Tables 1 - 3

The computer code performs 3D finite element crack closure analysis employing the remeshing concept. The code requires Intel MKL Library with the subroutine PARDISO for solving linear system equations. 3Dvmscode_20171016.txt - the 3D crack closure code with the remeshing concept implanted datainp_x64y004n25t1 - input file for the center crack specimen with a thickness of 2 mm datainp_x64y01n20t2 - input file for the center crack specimen with a thickness of 4 mm datainp_x64y02n25t5 - input file for the center crack specimen with a thickness of 10 mm datainp_x64y02n25t10 - input file for the center crack specimen with a thickness of 20 mm