A new method for the determination of cushion curves

Abstract

A new method for the measurement of shock-absorbing characteristics of cushioning materials and determination of`cushion curves' is discussed in this paper. The method not only signi®cantly reduces testing time but also improves the accuracy of the estimate of a cushion curve. Cushion curves are determined from the material's static compression characteristics and the impact data (static load/peak acceleration) obtained from a small number of impacts on a cushion tester. However, the method is capable of producing a cushion curve from the measurement of just a single impact. The process involves an iterative least mean squares (ILMS) minimisation of the discrepancy between peak acceleration values predicted from a theoretical model and measured in the impact tests. The algorithm of the ILMS method, examples demonstrating its application and the dynamic effect in impacts of various materials such as the EPU, the EPS and corrugated ®breboard are presented.

Modeling and Analysis of Cushioning Performance for Multi-layered Corrugated Structures

“…In recent years, alternative methods were developed to obtain cushion curves in a significantly shorter time for testing (Burgess, 1990;1994;Sek et al, 1997;2000). Representatives of alternative methods are the dynamic stress-energy method (Burgess, 1990;1994) and the single compression data method based on a quasidynamic compression test (Sek et al, 1997;2000).…”

Nonlinear Dynamic Analysis of Series Cushioning System Made with Expanded Polyethylene and Corrugated Paperboard

“…The most commonly used method of designing packaging structure is dynamic cushion curve, namely, the maximum-static stress curve method [1], which shows how a particular packaging material of a given thickness behaves at different impact loading. However, the cushion curves are commonly obtained through abundant experiments that would consume much time and expenditure.…”

Numerical simulation of a collapsible non-linear structure subjected to impacts

“…Such multilayer material, when subjected to significant impacts, may exhibit a collapse of layers and this dissipative effect may be utilized for shock attenuation [3]. For monotonically hardening cushioning materials, with their near half-sine shock pulses, the so called cushion curves are sufficient characteristics for optimization of their behavior [4]. Shocks produced by a collapsing material and their frequency content are more complex.…”