I have a PVC fitting that keeps cracking. The fitting consists of 2 parts. One piece is placed over the end of a flexible PVC ribbed hose, and the other is inserted inside the hose. The 2 parts act as a compression fitting to attach to the end of the hose. The hose typically has an outside diameter of 1.85". When the internal part is screwed into the hose, it expands the hose's outer diameter to 1.9". The inner diameter of the external part is 1.8". How do I calculate the stress exerted by the compressed hose material on the external part of my fitting?