Introduction to longitudinal vibration
Longitudinal vibration is the vibration of the cross section of the hull along its longitudinal axis in reciprocating tension-pressure. The vibration of the hull is classified according to the form of the hull vibration, which can produce longitudinal vibration, vertical vibration, horizontal vibration and torsional vibration. Only when the center of gravity of all transverse sections of the hull and the centroid of the longitudinal section of the hull are on the same straight line, the above-mentioned vibrations occur independently. Since the hull does not meet this condition, horizontal vibration and torsional vibration appear simultaneously, and vertical and longitudinal vibration occur simultaneously.