For circumferential joint in boilers, the type of joint used is

The cracks in helical springs used in railway carriages usually start on the inner side of the coil because of the fact that

Soderberg relation is based on __________ of the material whereas all other failure relation for dynamic loading are based on ultimate strength of the material.

When a closely coiled helical spring is subjected to a couple about its axis, the stress induced in the wire material of the spring is