*Start of Readme.txt*
Interacting surface defect results, Mk 1.0
Copyright Harry Coules 2016

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This file last edited on 13/06/2016.

%INTRODUCTION
These files contain the results of a large number of finite element models of interacting semi-elliptical surface cracks in plates of finite thickness. The models were performed as part of the work described in:
H. E. Coules, "Stress intensity interaction between dissimilar semi-elliptical surface cracks", International Journal of Pressure Vessels and Piping, 2016.

%FILES INCLUDED IN THIS DATASET
Readme.txt
results_const_nu_02.mat
results_const_nu_03.mat
results_const_nu_04.mat
results_cubic_nu_03.mat
results_linear_nu_03.mat
results_quadratic_nu_03.mat
results_quartic_nu_03.mat
results_quintic_nu_03.mat

%SOFTWARE
These data files were generated using MATLAB R2013a (The Mathworks Inc., Natick, USA). They should be compatible with any subsequent version of MATLAB.

%DATA STRUCTURE
1. Files
	Eight .mat files contain the data. Each .mat file corresponds to one of the parameter sets described in Table 2 in the article. Each parameter set contains results for a different combination of loading state and material Poisson's ratio.
	
2. Structures found within the .mat files
	Each .mat file contains two data structures, named mainStruct and singleStruct. mainStruct contains the results of analyses performed with cracks in close proximity to one another, while singleStruct contains results of analyses performed for remote cracks. mainStruct additionally contains the interaction factors referred to in the paper, which result from comparison beteen stress intensity factors for the remote and interacting crack models.
	
3. Second-level structures
	mainStruct and singleStruct have the same basic arrangement. Each one contains a sub-structure (paramLogStruct) and a cell array (outputArray). The length of the sub-structure/cell array is the same as the number of different parameter combinations considered, which is 7350 for mainStruct and 1470 for singleStruct.
	
4. paramLogStruct
	This structure contains a log of all the parameter combinations used for each model, along with information relating to how it was executed. The most important sub-structures are:
		paramLogStruct.naturalParams - Contains the geometry of the crack pair in non-dimensionalised ('natural') form. The most important of these geometric parameters are specified in Section 2.1 of the accompanying paper. Others such as paramLogStruct.naturalParams.rpA2 relate to eg. crack tip mesh zone sizing.
		paramLogStruct.modelParams - Contains the geometry of the crack in the form used to specify it in the finite element model, i.e. in actual spatial coordinates.
		jobExitStatus - Logical to indicate if the finite element model ran successfully. Some models encountered numerical problems, or (more often) were not attempted in the first place due to eg. insufficent distance between cracks for reliable mesh generation.

5. outputArray
	Cell array containing the finite element results. The fields include k (Stress intensity factors), j (j-integral), and t (elastic T-stress). For mainStruct.outputArray, there are also interaction factors and global interaction factors, as defined in the paper.

%EXAMPLE
This example demonstrates how data mat be extracted from these files using Matlab.

Q.
What was the interaction factor at the deepest point of Crack 2 for the geometric case shown in Figure 9a of the paper, with a Poission's ratio of 0.3 under uniform stress?

A. 
>> load('results_const_03.mat')
>> mainStruct.outputArray{1,3347}.interactionFactor{1,2}(5,26)
ans = 1.1060

The file results_const_03.mat contains results for uniform tension loading of a material with Poisson's ratio = 0.3. The case shown in Figure 9 is number 3347, and this can be verified by comparing the geometry pictured to the parameters specified in mainStruct.paramLogStruct(3347).naturalParams. the sub-array .interactionFactor{1,2} contains interaction factors for Crack 2. We want the result evaluated using outermost available mesh contour (#5), at the deepest node on the crack tip line (#26).

nB. All cracks were meshed using 51 nodes placed equidistant along the crack tip line. Concentric rings of elements around the crack tip line enabled contour integration over fixed radii. Results are given for five contour integration regions, and can therefore be checked for contour-independence.

%CONTACT
harry.coules@bristol.ac.uk

*End of Readme.txt*