Shock strengthening

Figure 6.3. Stress-strain response of shock-loaded 6061-T6 A1 as a function of peak shock pressure showing minimal shock strengthening.

This paper derives an extension to Chisnell s law. An analytic expression for the change in strength of a shock propagating into a varying area duct with isentropic flow ahead of the shock is derived. When the shock is moving into a region of lesser area the shock strengthens when conditions ahead of the shock are subsonic and weakens when conditions ahead of the shock are supersonic. The initial value problem and the stability of the shock are discussed qualitatively. 

Dieter, G.E., Hardening Effect Produced with Shock Waves, in Strengthening Mechanisms in Solids, American Society of Metals, Metals Park, Ohio, 1962, pp. 279-340. 

Zukas, E.G., Shock-Wave Strengthening, Metals Engrg. Quart. 6, 1-20 (1966). 

Strengthened by absorption of high-energy neutrinos, the shock wave expels the outer layers. Seen from outside, the star appears to have exploded. On Earth, this fabulous event is greeted with the joyous shout of Supernova ... 

Rou Gui is warmer and sweeter than Gui Zhi but is not as pungent. It can strengthen the vital gate fire, the Kidney-Yang, and treat restlessness, becoming nervous easily, frightened or shocked due to Kidney-Yang deficiency. 

Thermochemical data for alkyl amino radicals show for alkylhydrazines a trend in D (N-N) for these compounds in which the N-N bond was strengthened by increasing the degree of substitution by methyl in NH2 NH2 . From these values it was possible to determine values for the enthalpies of formation of the alkylamino radicals , and to confirm these by electron impact studies. The latter values were found to be in agreement with those obtained from pyrolysis studies. Hydrazine has often been used as a source of amino radicals by pyrolysis flame decomposition shock tube decomposition , electrodeless discharge and microwave discharge , viz. 

The neurotropic activity of five new oximes 8-11 and 13 has been studied (Table 4). Carbon derivative 8 was the most toxic compound (LD50 355 mg/kg). The stimulating effect of phenamine strengthened under the influence of germanium derivative 11 by 266%, but silicon derivative 9 decreased it by 55%. 5-Trimethylgermyl-2-furyltrifluoroacetyloxime (9) in comparatively small doses (50 mg/kg) completely prevented retrogradal amnesia caused by electric shock (RA 100%). 

Thermal shock resistance of Cr-Re alloys was sufficient to withstand conditions similar to those imposed by the application. The ability to mechanically twin permitted the accommodation of thermal deformation in the boundary area between the hot and cold zones of the combustion chamber, which is acknowledged to be the its most solicited area. Grain boundary micro cracking on the thermally shocked surface might be overcome by strengthening of the grain boundaries through thermo mechanical treatment. 

The introduction of surface compressive layers can strengthen ceramics and is a well-established technique for glasses (see Sec. 13.5 for more details). The underlying principle is to introduce a state of compressive surface residual stress, the presence of which would inhibit failure from surface flaws since these compressive stresses would have to be overcome before a surface crack could propagate. These compressive stresses have also been shown to enhance thermal shock resistance and contact damage resistance. 

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