how to solve an integral

hi everyone , this is my code:

clc
clear all
syms A m n r teta omega
E=200;h=.1;now=.2;D=400;row=7.8;l=.2;l1=pi/6;
G=E/(2*(1+now));gama=20;
syms a11 a21 

   m=1;
       n=1;
          mow=(2*m-1)*pi/2;
          alpham=(sin(mow)+sinh(mow))/(cos(mow)+cosh(mow));
          fr=a11*(sin(mow*r/l)-sinh(mow*r/l)-alpham*(cos(mow*r/l)-cosh(mow*r/l)));
          mow1=(2*n-1)*pi/2;
          alpham1=(sin(mow1)-sinh(mow1))/(cos(mow1)-cosh(mow1));
          fteta=a21*(sin(mow1*teta/l1)+sinh(mow1*teta/l1)-alpham1*(cos(mow1*teta/l1)+cosh(mow1*teta/l1)));
          w=fr*fteta;

drw=diff(w,1,'r');
dtetaw=diff(w,1,'teta');
nr=(E*h/(1-now^2))*((.5*(drw)^2)+(now/r)*((dtetaw)^2/(2*r)));
nteta=(E*h/(1-now^2))*(now*(.5*(drw)^2)+(dtetaw)^2/(2*r^2));
nrteta=G*((drw*dtetaw)/r);
u1=(1/(h*E))*(nr^2+nteta^2-2*now*nr*nteta+2*(1+now)*nrteta^2);
u1=u1*r;
U11=int(int(u1,r,1,3),teta,0,pi/6);

but although this seems simple ,matlab doesnot solve that and its busy for hours without any error or any answer.this is very important for me,Any help setting up this integral would be much appreciated.

Thank You.