# fourthOrderMat

Below is a demonstration of the features of the `fourthOrderMat` function

## Contents

```
clear; close all; clc;
```

## Syntax

`[CM]=fourthOrderMat(C);`

## Description

Converts a 3x3x3x3 4th order tensor to a 9x9 matrix

## Examples

Creating the stiffness tensor for Hooke's law of linear elasticity

%Constructing 4th order base tensor set I=eye(3,3); %The 2nd order identity tensor II1=dyadicProduct(I,I,1); %4th order base tensor 1 II3=dyadicProduct(I,I,3); %4th order base tensor 3 %Parameters for Hooke's law mu=1; %The shear modulus lambda=5; %The lambda lame parameter C=lambda.*II1+2.*mu.*II3; %Construct 4th order stiffness tensor

[CM]=fourthOrderMat(C)

CM = 7 0 0 0 1 0 0 0 1 0 5 0 1 0 0 0 0 0 0 0 5 0 0 0 1 0 0 0 1 0 5 0 0 0 0 0 1 0 0 0 7 0 0 0 1 0 0 0 0 0 5 0 1 0 0 0 1 0 0 0 5 0 0 0 0 0 0 0 1 0 5 0 1 0 0 0 1 0 0 0 7

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*Kevin Mattheus Moerman*, [email protected]

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