Introduction Throughout the distribution system, packages are manhandled and mishandled in various ways dropped, thrown, kicked and otherwise roughly abused fall from conveyors or forklifts and crash to the floor subjected to a variety of vehicle impacts; trucks starting, stopping, hitting chuckhole and railroad crossings, railcar humping, jolting and other moderately violent actions suffers an impact with another object: floor, truck bed, pallet, bulkhead or another package. A mechanical shock occurs when an object's position, velocity or acceleration suddenly changes. Such a shock may be characterized by a rapid increase in acceleration followed by a rapid decrease over a very short period of time. Figure 13.1: the acceleration versus time plot for most shocksIntroduction ◼ Throughout the distribution system, packages are manhandled and mishandled in various ways: dropped, thrown, kicked and otherwise roughly abused; fall from conveyors or forklifts and crash to the floor; subjected to a variety of vehicle impacts; trucks starting, stopping, hitting chuckholes and railroad crossings, railcar humping, jolting and other moderately violent actions; suffers an impact with another object：floor, truck bed, pallet, bulkhead or another package. ◼ A mechanical shock occurs when an object's position, velocity or acceleration suddenly changes. Such a shock may be characterized by a rapid increase in acceleration followed by a rapid decrease over a very short period of time. ◼ Figure 13.1: the acceleration versus time plot for most shocks