The cells in conventional packaging foams have random size and orientation, and the energyabsorbing behaviour of these foams is determined by the collective contribution of different sizes of cells. In contrast to the random nature of stochastic foams, 3D printing technologies allow engineers to design and produce foams having engineered cellular structures. In this study, engineered cellular structures based on the classic Kelvin 1887 model were 3D printed in 30 × 30 × 30 mm thermoplastic polyurethane cubes with a repeating size of 216 unit cells.One hundred consecutive cyclic compression tests were performed to assess the 3D printed foam's resilience and energy absorption characteristics. The stress-strain curve of the 3D printed thermoplastic polyurethane foam indicated viscoelastic behaviour and a Mullins effect indicative of resilient rubber. A long wave buckling mode was observed during cyclic compression cycles due to the Kelvin structure. The cushion factor computed from the stress-strain curve was close to that of a metal spring with linear elasticity. The combination of the 3D printed foam's resilience, its much lower density than rubber, and the complete geometric freedom of the engineered cellular structures offer designers the potential to create high-performance cushion materials tailored for packaging applications.

A widely used industrial felted foam was compared to a volumetrically heated and compressed foam in this study in terms of cushion performance. The off-the-shelf melamine open cell foam and polyurethane open cell foam were triaxially heated and compressed via an in-house-made device, and energy dissipation was then compared to the felted off-the-shelf open cell melamine and the polyurethane foam. The hysteresis cycle compression test and impact test, in conjunction with a high-speed video camera, were conducted to measure the energy dissipation, G-value, and the Poisson's ratio. Scanning electron microscopy was used to investigate the cellular morphology before and after the felting and volumetric heat and compression. The study showed that both felted foam and triaxial compressed foam demonstrated reasonably well the cushion performance due to the presence of auxetic and microcell structures.

A field measurement study, using a combination of controlled and uncontrolled phases, examined low‐acceleration, long‐duration events occurring during over‐the‐road truck transport. A field data recorder equipped with a DC‐based triaxial accelerometer was employed for this study to capture the steady‐state nature of these event types. The field data recorder was rigidly mounted to the trailer chassis to record lateral and longitudinal events of interest. The controlled phase recorded normal and aggressive braking events and traversing a roundabout to fundamentally quantify the behaviour of the vehicle. For the controlled phase, average decelerations of 0.27 and 0.45 g were reported for normal and aggressive braking events, respectively. Lateral accelerations from traversing a roundabout were on average 0.40 g. The uncontrolled field measurement study, which evaluated the transport vehicle over 13 days, reported average longitudinal decelerations and lateral accelerations of 0.29 and 0.34 g, respectively. The rise times associated with these events were also reported. The jerk was calculated based on the rise times for the controlled and uncontrolled phases and compared to currently available test procedures. For both project phases, composite test profiles were developed based on field‐measured levels. The resulting composite test profiles can be utilized to evaluate the load stability of a unit load system travelling through this distribution channel.

The practice of developing cushion curves has been applied for many years. Known for its tedious development, the process does not correlate to cushion configurations too. This study reviewed conventional theories, practice of cushion curves, and simplified methods, including the conversion from quasi-static compression chart to cushion curves, and testing-extrapolated methods based on several applicable tests.In addition, the study examined the effect of configuration on cushion curves. Discussion indicated that the theories of cushion curves are based on two fundamental properties in physics: energy conversion and Newton's second law. Energy density-based test-extrapolation approaches reduced the development time significantly without compromising the accuracy of the cushion curves. The edge and corner cushion structure showed a similar pattern to the conventional flat cushion curve, but were shifted horizontally to the right. This paper recommends packaging engineers to apply C-e curves as the basis of the cushion curves to design cushioning. Finally, energy dissipated during platen drop test is discussed to explain the deformation process in relation to dynamic stress-strain curve and cushion curve.

Most cushion structures used in the industry are end caps, edge or corner foam. The bearing area and thickness of the cushioning obtained from cushion curves apply, in principle only, to flat foam because the specimens used to develop the cushion curves are flat foam samples. This study is aimed at finding the difference between the two foams in stress-strain relationship and dynamic impact. A hysteresis cycle compression test, in conjunction with digital image correlation techniques, and a shock cushion test were performed to assess the static stress and strain, energy dissipated and maximum acceleration of flat and corner foams. The study found that the static stress of the corner foam that occurred during the compression testing is 23% higher in average than the flat foam, depending on the compression speed. The shock cushion curve of the corner foam showed a similar pattern as the flat cushion curve but was shifted horizontally to the right as a result of the increased static stress. This study recommends that the conventional cushion curve should be shifted to the right horizontally by about 23-35% in order for a packaging designer to apply it for corner foam.