%% Function name
%       alpha_gtol

%% Revised:
%       13 January 2014
 
%% Author
%       Atif Amir, Trey Moore, & Autar Kaw
%       Section: All 
%       Semester: Fall 2012
 
%% Purpose
%       Given the longitudinal and transverse coefficients of thermal 
%       expansion of a unidirectional lamina, and the angle of the ply, 
%       output the coefficients of thermal expansion for an angle lamina.
 
%% Usage
%       function [alphaxy] = alpha_gtol(alpha12,angle)
% Input variables
%       alpha12=vector of thermal expansion of unidirectional lamina 
%               in 1,2 direction 
%       [alpha12]=[alpha1;alpha2;zero]
%       alpha1=longitudinal coefficient of thermal expansion
%       alpha2=transverse coefficient of thermal expansion.
%       alpha12=in-plane coefficient of thermal expansion.
%       angle=angle of ply in degrees
% Output variables
%       alphaxy=vector of coefficients of thermal expansion for angle
%               in x,y direction
%       [alphax,alphay,alphaxy]
% Keywords
%       coefficient of thermal expansion 
%       angle ply

%% License Agreement
%       http://www.eng.usf.edu/~kaw/OCW/composites/license/limiteduse.pdf

%% Testing Code
clc
clear all
%% Inputs
% Material:  Glass/Epoxy
alpha1=8.6E-6;
alpha2=22.1E-6;
[alpha12]=[alpha1;alpha2;0];
fprintf('\nLongitudinal Coeff. of Thermal Expansion: %g ',alpha1)
fprintf('\nTransverse Coeff. of Thermal Expansion: %g ',alpha2)
%% Test 1
% Testing for individual angle
% Input desired angle in degrees
angle=60;
% Call function: alpha_gtol
[alphaxy] = alpha_gtol(alpha12,angle);
% Results for a particular angle
fprintf('\n\nAngle of Lamina: %G\n\n',angle)
disp('    Lamina Coefficient of Thermal Expansion')
disp('___________________________________________________')
fprintf('\n alphax   | %G\n alphay   | %G\n alphaxy  | %G\n\n\n\n',...
    alphaxy(1),alphaxy(2),alphaxy(3))
%% Test 2
% Table of Thermal Expansion Coefficients of an Angle Lamina
% as a Function of Fiber Angle
for i=1:5:91
    angle(i)=i-1;
    [alphaxy] = alpha_gtol(alpha12,angle(i));
    alphax(i)=alphaxy(1);
    alphay(i)=alphaxy(2);
    alpha_xy(i)=alphaxy(3);
end
disp('          Lamina Coefficient of Thermal Expansion')
disp('_________________________________________________________________')
disp('  angle          alphax             alphay          alphaxy  ')
for i=1:5:91
   fprintf('\t%2.0f |\t  %E |\t %E |\t %E \n',angle(i),alphax(i),alphay(i),alpha_xy(i))
end
%% Test 3
% Graph of Thermal Expansion Coefficients of an Angle Lamina
% as a Function of Fiber Angle
for i=1:1:91
    angle(i)=i-1;
    [alphaxy] = alpha_gtol(alpha12,angle(i));
    alphax(i)=alphaxy(1);
    alphay(i)=alphaxy(2);
    alpha_xy(i)=alphaxy(3);
end
hold on
plot(angle,alphax,'b','LineWidth',2)
plot(angle,alphay,'r','LineWidth',2)
plot(angle,alpha_xy,'m','LineWidth',2)
grid
legend('alphax','alphay','alphaxy')
title('Coefficient of Thermal Expansion vs. Fiber Angle')
xlabel('Angle (degrees)')
ylabel('Coefficient of Thermal Expansion')
hold off