5^^ 



141 



0.05 



0.10 



,2 



0.15 



0.20 



0.25 



0.30 



0.35 



-^ Square of Proportionate Deflection 



Figure ^6 - Energy Plotted against Square of Deflection 



The curves plotted are averages of the data obtained on the platea tested. This graph Indicates 

 that energy absorbed by a thin circular plate may be approximately computed from Equation [19] 

 when j/a > 0.2. The appropriate values of a for the different materials are as folloiis: 



Special Treatment Steel 0.97 High Tensile Steel 0.88 



Furniture Steel 0.93 Copper 0.8A 



Medium Steel 0.81 



less than those of the pressure curves. Since the energy curves represent 

 Integrations of the pressure curves, the lower values of a In Figure 46 can 

 be ascribed to the relatively low values of pressure in Figure 45. 



CONCLUSIONS 



Thin metal plates deformed by static pressure approximate membranes 

 in their behavior. From a knowledge of the ultimate strength of the material 

 and the dimensions of a plate, estimates of the deflection and of the energy 

 absorbed in the plastic range can be made on the basis of membrane theory if 

 the tension is taken to be aa^h, where a can vary between about 0.8 and 1.02. 



