Equivalent Drop Test Modification for Determination of Cushioning Performance

摘要

There are two main testing methods for cushioning performance of the transport packaging: One is the dynamic compression test which uses simple shapes of material and the other is the equivalent drop test-the shock test, which is based on the traditional equivalent drop theory. Because of limitations of the traditional theory, the traditional equivalent drop test causes errors in many cases. For this reason, by introducing the concept of the velocity correction coefficient that can be expressed by a parameter of the damping ratio, a new attenuation equivalent drop theory (modified theory in this paper) based on the traditional theory is proposed in this paper. Subsequently, two different correcting methods that are based on the modified theory are proposed. In order to verify the viability of the new theory, expanded polyethylene is used as a test material, and the dynamic compression test and the shock test based on the traditional theory and the modified theory respectively are performed. Finally, the results of two tests are compared. Verification experiments show that the modified theory can improve the equivalent precision of the two tests, and one of the two correcting methods is superior to the other.