Gregory S. Batt

Application of the Stress-Energy Method for Generating Corrugated Board Cushion Curves

Cushion curves are an important tool used for designing foam cushions, but no commercially available curves exist for corrugated board, despite its growing popularity as a cushioning material. This paper summarizes the theory and recent work applying the stress-energy method and different curve fit models to corrugated board for generating cushion curves. This paper also compares stress-energy predicted deceleration values to actual ASTM D1596 deceleration values as a method of determining whether the stress-energy method is a viable alternative for generating cushion curves for corrugated board. The results of this study suggest that the stress-energy method should not yet be recommended for generating cushion curves for corrugated board.

Prediction of Cushion Performance Less Than One Inch Thick

An important tool packaging engineers use when designing cushions to protect products from shock is the cushion curve. Cushion curves show deceleration values along the vertical axis versus the static loading (weight divided by bearing area) along the horizontal axis for a given thickness of cushion material and given drop height. Commercially available cushion curves display a thickness of one inch and greater. However, many times packaging engineers design packages with cushions less than one inch thick. This leaves the packaging engineer to either guess deceleration levels below one inch thick by trial and error, or to extrapolate from existing cushion curve data. The purpose of this study was to determine if using existing cushion curve information would accurately predict deceleration values below one inch thick. To do this, a procedure was developed comparing information collected from expanded polystyrene cushion samples greater than one inch thick (correlating to existing cushion curves) compared to information collected from samples less than one inch thick. The comparison looked for difference between the datasets. It was found that in fact there was a statistical difference, meaning existing cushion curves should not be used to predict deceleration values for cushion thicknesses below one inch.

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.

A review of laboratory methods and results used to evaluate protective headgear in American football

As head trauma becomes more firmly associated with American football, research has focused on improving the impact performance of protective headgear. Since helmet use became mandatory in 1939–1940, both helmet design and laboratory methods used to evaluate helmet impact performance have evolved. Through a comprehensive review of the literature, this article analyzes the impact results from laboratory evaluations of helmet performance, including a look at the evolution of protective headgear performance in football. In total, 35 separate studies conducted between 1975 and 2017 were used to examine current testing methodologies and reported impact results from headgear performance laboratory assessments. This review showed that the evolution in helmet design over the last 50 years has resulted in a decrease in linear and rotational acceleration of an impacted headform. The most common laboratory methods used to reconstruct football-specific head impacts included (1) linear drop methods, (2) pendulum methods, and (3) pneumatic ram methods. Each method provided greater understanding of helmet impact performance, helmet design, and use in football, with each method having specific limitations in the evaluation of protective headgear performance.