Effect of Stretch Wrap Parameters on the Transmissibility of Unitized Loads Excited by Random Vibration

Abstract

The vibratory response of two unit load systems stretch wrapped with a high-performance stretch film was investigated. The two unit loads selected contained two different product types, one containing chips packaged inside a flexible bag placed inside a paperboard carton, while the other was liquid flavoring packaged inside a rigid plastic container placed into a corrugated regular slotted container. The unit load systems were stretch wrapped using 12.7 micron high-performance stretch film. The application of the stretch film was altered to produce negative, neutral, and positive total stretch scenarios. Results from the study showed negative total stretch scenarios allowed the tertiary containers to have greater vertical displacement increasing potential for abrasion and dynamic compression failures. Neutral and positive total stretch scenario limited vertical motion as compared to negative total stretch scenarios. Results indicated the secondary packages for both product types were not affected by the different stretch wrap scenarios. Additionally, this project provided a methodology to evaluate different film grades and stretch wrap parameters and how they affect the unit loads response when excited using industry standard random vibration power spectral density (PSD) profiles.