Impact and vibration testing of shipping containers

Equations are developed for experimental evaluation of restoring and dissipative parameters, as used in a non-linear mathematical unit load model. A specially developed transportation damage simulation test jig is described. This jig is suitable for impact and vibration load reproduction on bottom tier containers in unit loads, but only a single container sample is needed. A detailed case study is described, exemplifying how these parameters may be evaluated by impact (shock) or vibration testing of corrugated produce shipping containers. The initial spring rate K₀ was found to be approximately equal in impact and vibration loading. The parameter r, expressing the non-linearity, was significantly larger in vibration loading than in impact loading. On the other hand, both viscous and Coulomb damping are significantly greater in impact loading than in vibration loading. The same modus operandi may be used for determination of dynamic restoring and dissipative parameters of other products, such as cushioning foams and elastomers.