Experimental study on vibration transmissibility of Pre-loaded XPE and PE packaging cushioning material

Most of the shipped products are sensitive against shock and vibration events during the distribution. Various cushioning materials are usually used to prevent the product damages. During the design process the protective packaging system is developed by the engineers based on the cushion and vibration transmissibility features (ie. cushion curve) of the material used. However, after the assembly of the packaged-product, these are stored for various long periods in warehouse. During this time the products pre-load the cushioning material and its parameters can be changed. The main goal of this study is to evaluate the vibration transmissibility of PE and XPE cushioning material at varied storage (pre-loaded) time and static load conditions. Four different kinds of duration (1 hour, 10 hours, 100 hours and 1000 hours) were used for the pre-loading period at three different static loads (3.488 kPa, 4.651 kPa, and 6.976 kPa), and then at 0.5 oct/min sine sweep vibration the peak frequencies of response and vibration transmissibility, and damping ratio were determined. The results show that the effect of pre-loading is minimal by PE material, but can influence the resonance frequencies by XPE cushioning material. The findings of this study help the packaging engineers to understand better the mechanism of these cushioning materials and to design suitable protective packaging systems.

Combination of Hardware and Control to Reduce Humanoids Fall Damage

Most existing motion control methods for humanoids aim at avoiding falling. However, the humanoid is generally an unstable system that cannot completely avoid falling and it is difficult to cope with the sudden fall of a robot. This paper designs a planning method of fall protection for humanoids according to the human falling motion. This method changes the impact position between the robot and ground by adjusting the motion of the robot as it falls. To further reduce damage to the robot, an appropriate cushioning material is installed at the point of impact to buffer the robot. The effectiveness of the proposed method is verified for a BHR6P humanoid robot falling in simulations and experiments.

Characteristics of Truss Core Created by Origami Forming Method

The truss core surpasses the honeycomb core depending on the tasks. The height of core is limited by press forming and so on. Therefore, we developed a method by folding mountain / valley lines like origami. The origami forming method has the feature that it can be done from paper to metal by the same method. By examining three-point bending tests, drop tests, and analyzing them, we show that the structure that space-filled with cores obtained by the origami forming method called ATCP will be a box for both excellent cushioning material and transporting. Moreover, we also show that the core structure obtained by this has excellent sound insulation performance.

Study of Physical Properties and Shock Absorption Abilities of Starch Polymer Foam as Cushioning Material for Packaging

Lack of information about the formulation and fabrication process of starch polymer foam and lack of study in the shock absorption ability of starch polymer foam were the reasons this research was executed. In this project starch polymer foam was produced to be used as cushioning material for packaging. Starch polymer foam were developed from starch, polyvinyl alcohol (PVA), urea, citric acid, and deionised water. Water amount with drying and curing process were the variables manipulated to produce the best starch polymer foam. It was determined then, that the optimized ratio of starch:PVA:citric acid was 1:1:4. The amount of water used was 10 ml/gram of starch/PVA weight. The suitable foaming mixing was done at a speed of 1500 rpm for 40 minutes. Drying process was done at 70°C for 24 hours, followed by curing process at 100°C for 1 hour to produce closed-cell foam. While for the open-cell foam, the foam was dried and cured at 100ºC for 6 hours. The open-cell and closed-cell foams produced were cut to 6 cm height x 6 cm width x 0.5 cm thick. The average density was calculated and then the foams were subjected to weight drop destructive test. The test was done by placing a foam on top of a piece of mirror, and a weight is dropped onto the foam, with increasing height until the mirror break. Three weights were used with mass of 50 g, 100 g and 200 g. The starch foams were compared to polyurethane and polystyrene foams in terms of the minimum height that can cause the mirror to break. The results showed that starch closed-cell foam absorbed the highest impact energy followed by polystyrene foam, starch open-cell foam and polyurethane foam.