function [Tnd]=T_stress(a,rea,num,x);%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% The function tfac calculates the compressive T stress, by% calculating K_I(a,b)=f_I*stress*Sqrt(pi*a)% f_I, is given in  *)"Stress Intensity factore Handbook Vol 1."% The Society of Materials Science, Japan, Pergamon Press 1987%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%  INPUT :%%%%%%%%%%%%%%%%% 	a  	=	crack length %	rea	=	reaction forces in top nodes of panel%%  OUTPUT :%%%%%%%%%%%%%%%%	Tnd	=	non-dimesionailised T-stress.%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%                  Constants                                            %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%	a=round(a);	alpa=a/W	c=W-a;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%		Main Routine						%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 		Center Crack Panels					%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Changes  for center crack panels was made the d. 30 April 1994, as% the beta values, had to be corrected for the deeply crack panels    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%          if num==1;  		fm=[1 1.006 1.025 1.058 1.109 1.187 1.303 1.488 1.816 ...                   2.3118]; % *) 		al=[0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9]; % *)	if alpa <= 0.6 		Beta=-(1+0.085*(2*a/W));	else                 if alpa==0.7 		Beta=-1.261;		end		if alpa==0.8		Beta=-1.460;		end		if alpa==0.9		Beta=-1.93;		end 	end	 end;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%		Singel Edge Crack- Tension (displacement loaded)        %%  Changes in f_function	d. 18/8-94 		  		%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%                if num==2; 		beta=[-0.464 -0.434 -0.371 -0.278 -0.153 0.69e-2 ...		0.21 0.501 0.103e1];                al=[0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9];% obs 19/8-94   f=1.12-0.23*alpa+10.55*alpa^2-21.72*alpa^3+30.39*alpa^4;   		f=(2*tan(pi*alpa/2)/(pi*alpa))^0.5* ...   		(0.752+2.02*alpa+0.37*(1-sin(pi*alpa/2))^3)/cos(pi*alpa/2);        end;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 		Single Edge Crack - Bending 				%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%       if num==3;   		beta=[-0.363 -0.229 -0.07344 0.0921 0.262 0.433 0.610 0.839 0.126e1];				                      						al=[0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9];                f=1.122-1.40*alpa+7.33*alpa^2-13.08*alpa^3+14*alpa^4;                 [m,n]=size(rea)                 for i=1:n;                 M(i)=0.0;                 for j=1:m;                 M(i)= M(i)+(x(j)-c/2)*rea(j,i);                 end;                 M=abs(M);                 end; 		end;%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%		   Double Edge Crack  					%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%	if num==4;                 beta=[-0.436 -0.445 -0.458 -0.463 -0.471 -0.441 -0.411 ...                 -0.33 -0.196];                 al=[0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9];                 f= 1.222-0.154*alpa+0.807*alpa^2-1.894*alpa^3+2.494*alpa^4;                 end;   [g,h]=size(al);if num~=1 % for CCP Beta is given by a function rather than vector 		for i=1:h				if al(i)==alpa				Beta=beta(i);								end;		end;else		for i=1:h				if al(i)==alpa				f=fm(i);								end;		end;end;		if num==3;				for i=1:n;				Tnd(i)=6*M(i)*f*Beta/(W^2*s0);				end		else					[m,n]=size(rea);					if m~=1					p=sum(rea);  					else 					p=rea;					end				Tnd=Beta*f*abs(p)/(W*s0);		end;