How to calculate the deflection in ring, fixed at center, with a radial point force acting at some point(let say at theta=0) ? I have derived complete set of equations. Now how to apply boundary conditions ? to get a complete solution of 4th order equation, I need 4 B.C's, but here displacements are not specified at any point. Imposing periodicity I can get 2 more conditions u(0)=u(2*pi) w(0)=w(2*pi) where u and w are radial and tangential displacements respectively and how to apply force boundary condition in this case? Can someone please help?