The pipe section is circular and is characterized by its outer radius and its
thickness (in that order). There are 8 integration points equally distributed
along the circumference. In local coordinates, the radius at which the
integration points are located is 
![]() , where
, where ![]() ,
, ![]() being the inner radius and
being the inner radius and ![]() the outer radius. The weight for each
integration point is given by
 the outer radius. The weight for each
integration point is given by 
![]() [12].
 [12].