lesson15-全文預(yù)覽
【正文】 product, which presents a static load of psi. ? In this case, the coefficient is . Using the formula T x W/T = W, you can now find the minimum width: 3x = . Your cushion must be at least inches wide or long to resist buckling. 3. Consider Extreme Temperature Effects Step 4 Recognizing Design Constraints ? As with all thermoplastic foams, when they are exposed to extremely high or low temperatures over a considerable length of time, they may be affected. ? The materials bee stiffer at low temperatures and increasingly softer at higher temperatures. In extreme cases, it may bee necessary to pensate for these effects in your design. Step 5 Design Prototypes and Test ? Each packaging design must be developed separately, given the large number of variables involved. ? It is highly remended that you build and test a prototype of your cushion design to determine its actual performance. Step 6 Consider Vibration Effects Table Typical forcing frequencies of carriers Carrier Frequency Range Conditions Railroad 2 7 Hz (suspension) Moving freight car 50 70 Hz (structural) Truck 2 7 Hz (suspension) Normal highway travel 15 20 Hz (tires) 50 70 Hz (structural) Aircraft 2 10 Hz (propeller) On aircraft floor during flight 100 – 200 Hz (jet) Ships 11 Hz (on deck) Vibrations caused by 100 Hz (bulkheads) interference to the flow of water by the ship, and from imbalance and misalignment of the propeller shaft system. Step 6 Consider Vibration Effects ? Every mode of transport subjects the packages being shipped to some amount of vibration at various frequencies. ? In order to provide products which are prone to vibration damage with protection against such effects, it is essential to determine the natural frequency of any ponent which is prone to vibration damage, and pare it against the vibration characteristics of your package design. ? Every cushioning system has a range of vibrational frequencies in which it amplifies vibration and passes on a more severe vibration to the packaged product than it receives from the transport environment (Figure ). Step 6 Consider Vibration Effects ? For most vibrationsensitive products, making sure that the package design does not amplify vibration in the product39。s) on the vertical axi
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