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BELL SYSTEM TECHNICAL JOURNAL 



tially this characteristic. The mass of the cushioning is assumed to 

 be small in comparison with mo, except in Section 4.2. 

 The outer container is represented by the mass niz . The impact of 

 W3 on the floor is assumed to be inelastic and during contact the rela- 

 tive displacement between m^ and the initial position of the floor 

 is assumed to be small in comparison with the relative displacement 

 between Wo and ntz . In other words, no spring action is assigned to 

 the outer container and the floor is considered rigid. 



Element of 

 Packaged 

 Item ^: 



Packaged 

 Item 



Cushion 



Height 



of drop h 



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(a) (b) (c) 



Fig. 0.2.2 — Idealized mechanical s}stem representing a package in a drop test. 



PART I 

 MAXIMUM ACCELERATION AND DISPLACEMENT 



LI Introduction 



Most of Part I is concerned with the prediction of the maximum accelera- 

 tion that the cushioning permits the packaged article (W2) to attain. In 

 many instances this will be all the information necessary for judging the 

 suitabiHty of a cushioning system. It will be all that is necessary if the 

 shape and scale of the acceleration-time function satisfy certain criteria 

 which are treated in detail in Parts III and IV. If these criteria are satisfied, 

 the effect of the drop on the packaged article is found by multiplying the 



