Kyle Dunno

Experimental Comparison of Vehicle Vibration Simulation Techniques

Performing accurate vehicle vibration simulation is imperative to understanding the adequacy of a packaged products ability to withstand the rigors of transportation. Over the past decade, various vehicle vibration analysis techniques were proposed in order to provide better correlation to actual field shipments. This paper highlighted the observations made when an independent laboratory utilized four different methods in the simulation of vertical vibration and applied them to three different packaged products. A field data recorder was employed to record over-the-road vibration of a fully loaded steel spring truck traveling over interstates and highways. The collected data was analyzed independently using each of the different techniques and simulated in a lab with the necessary controller. This study is unique in that it considered the response of actual packaged products and through the use of a damage assessment tool, determined how well the techniques correlate with field vibration results. Additionally, two common industry vibration profiles were used to test the packaged products for comparison. The three packaged products used for these evaluations were a top-mount refrigerator, an electric hedge trimmer, and a gas-powered pressure washer. Results indicate that each of the proposed vehicle vibration analysis techniques produces product and package damage that correlates well with typical field vibration results for the three products tested. These results supported the further use of any of these techniques in the simulation of vehicle vibration.

Evaluation of Containment Force Variability between Different Grades of Stretch Film

Containment force is a measurement often used to qualify stretch films when they are applied to a unit load of packaged product. This measurement records the amount of resistance force a stretch film delivers when being displaced a specified distance. It has been the industry perception there are quality differences between commodity and high-performance grade stretch films. These perceived quality differences are believed to affect the variability between different grades when being examined in a laboratory. In order to evaluate this theory, two different grades of stretch film from two different manufacturers were applied to an instrumented test pallet and the containment force was measured. Results from this study showed there were no statistical differences between the variability of containment forces of different grades of stretch film between the same manufacturers. While the study was limited to only two manufacturers, the results indicated there is less variability between commodity and high-performance grade stretch films than was originally theorized. Additionally, it was observed that a predetermined containment force measurement of 25 lbs. could be obtained through a variety of different stretch wrapping parameters and equipment settings. Many of the developed patterns and settings used would have resulted in load shifting and/or load failures during actual transport. As a result of these observations, it was recommended to use containment force measurements as part of a quality assurance program and not a predictor of success during transportation.