ansys apdl basic error please solve
 

I am trying to analyse a two material cylinder glued together .The cylinder is subjected to internal pressure of 100 units. The problem i am facing is that the radial stress at the inner radius (where the internal pressure is applied) is not equal to the internal pressure.I.E. if the internal pressure is 100 units ,the radial stress at the inner radius is 98.23. It generally deviates by 2 to 3 percent.I am attaching a contour plot of the radial stress.
I have used the following properties;
young's modulus E1=1e5......E2=2e5
Poisson's ratio is 0.3 for both materials
Mesh properties: smart size no:1(fine)
free mesh
plane 182 has been used. It is a cylinder with zero height hence area has been defined.Only quarter cylinder is analysed and symmetric boundary condition has been implemented.
To find radial stress, rsys,1 command has been used