Axial Compression
The dimensional reduction or shortening of the face-to-face parallel length of the joint measured along the longitudinal axis.
Axial Elongation
The dimensional increase or lengthening of the face-to-face parallel length of the joint measured along the longitudinal axis.
Lateral Deflection
Lateral deflection is movement perpendicular to the axial plane of the expansion joint. It is a shear motion on the bellows.
Vibration
The movement of the joint due to vibrations which are effectively intercepted and insulated against transmission to the remainder of the system.
Angular Movement
The displacement of the longitudinal axis of the joint from its initial straight line position (a combination of axial elongation and axial compression).
Torsional Movement
The twisting of one end of the expansion joint with respect to the other end about its longitudinal axis.