Dynamic behaviour of a package under circulatory harmonic vibration

Vibration test is one of the performance evaluation tests for simulating th e transport environment under laboratory conditions for evaluation of packa ge - product integrity. The method of conducting vibration tests are prescr ibed in all national and international standards. The vibration test proced ure for repetitive shock tests for single container are vertical linear amp litude mode in which the amplitude is fixed at 25 mm and acceleration at 1 g level. The frequency calculated for the package to leave the table is 4.4 2 cycles/sec. But in actual vibration tests the package starts to rock at m uch below the calculated frequency for 1 g acceleration. This paper provide s the theoretical explanation for the rocking motion and the repeated impac ts to the package. Also it is observed-that the factors like 1. coefficient of friction between the package and the vibration table surf ace and 2. the center of gravity of the package plays a vital role for rocking of t he package.