IAM LOOKING FOR THE "DERIVATION" OF THE GOVERNING EQUILIBRIUM EQUATION
OF THE MEMBRANE STRUCTURES IN THE TRANSVERSE DIRECTION. I HAVE THE
FOLLOWING EQUATION FROM ONE OF THE TECHNICAL PAPERS ( LARGE
DEFLECTIONS OF AXISYMMETRIC CIRCULAR MEMBRANES - by Kao and Perrone
),BUT I WANT TO KNOW HOW THE EQUATION WAS DERIVED. THE EQUATION IS AS
FOLLOWS : (1/R)* d(R*Nr*(dw/dr))/dr + P = 0. WHERE 'R' IS THE RADIUS
OF THE CIRCULAR MEMBRANE, 'Nr' IS THE STRESS RESULTANT IN THE RADIAL
DIRECTION, 'P' IS PRESSURE APPLIED TO THE MEMBRANE IN THE VERTICAL
DIRECTION, 'r' IS THE RADIAL COORDINATE AND 'w' IS THE DISPLACEMENT
COMPONENT IN THE NORMAL DIRECTION.