scholarly journals Discussion: “Experimental and Theoretical Investigation of the Plastic Deformation of Cantilever Beams Subjected to Impulsive Loading” (Bodner, S. R., and Symonds, P. S., 1962, ASME J. Appl. Mech., 29, pp. 719–728)

1963 ◽  
Vol 30 (4) ◽  
pp. 637-637
Author(s):  
T. H. H. Pian
1962 ◽  
Vol 29 (4) ◽  
pp. 719-728 ◽  
Author(s):  
S. R. Bodner ◽  
P. S. Symonds

The experimental techniques and the results obtained in a program to evaluate the assumptions of dynamic, rigid-plastic theory of beams are presented. The experiments used steel and aluminum-alloy cantilever beams subjected to either a rapid velocity change at the base or to an impulsive load at the tip. A rigid-plastic theory that includes the strain-rate dependence of the yield stress and geometry changes is outlined for the case of the tip impulsive loading. The predictions of this theory are in satisfactory agreement with the experimental results.


1991 ◽  
Vol 14 ◽  
pp. 151-156 ◽  
Author(s):  
M. Berveiller ◽  
J. Krier ◽  
H. Ruppersberg ◽  
C. N. J. Wagner

1965 ◽  
Vol 32 (1) ◽  
pp. 7-10 ◽  
Author(s):  
John S. Humphreys

A series of tests was conducted on flat steel beams of various sizes and material properties, using sheet explosive to provide sufficiently high uniform impulsive loading to produce significant plastic deformation. The beams were attached to a ballistic pendulum for measurement of applied impulse, and were photographed with a Fastax camera during deformation. The resulting final deformations are compared with the rigid-plastic theory of Symonds and Mentel, which is seen to give upper bounds that are in general higher by about 20–30 percent than the deformations observed. A fairly good first approximation to maximum deflection for engineering purposes is in fact obtained simply by using rigid-plastic beam theory (including axial constraints).


Author(s):  
John M. Rickman ◽  
Jonathan Painter ◽  
Rachael Hazael

AbstractThe present paper presents a scanning electron microscope (SEM) analysis of the genesis and microarchitecture of experimentally induced cortical entry fractures in porcine scapulae impacted at velocities ranging from 54 to 897 m/s. SEM observation was conducted on polyurethane replicas cast from negative silicone moulds. Analysis of the sequence of fracture processes operative during projectile impact revealed the presence of ring cracks at the site of impact, confirming that penetration in sandwich bones is achieved by cone crack propagation. Despite impulsive loading, two forms of plastic deformation were identified in the cortical bone surrounding the entry fracture up to a maximum velocity of 871 m/s. Microscopic radial and concentric cracks were associated with projectile impact, and the role of pores and pits as stress concentrators was captured. Possible underlying mechanisms for the observed plastic deformation are described, and the diagnostic utility of SEM analysis is presented.


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