A method for evaluating stress intensity distribution for cracks in rocket motor bondlines

Two new processes of cylinder autofrettage (prestress) have been analyzed and compared to the standard high pressure autofrettage. By means of a highly improved stress intensity distribution at design pressure, it was shown that a significant increase in allowable pressure and a reduction of autofrettage pressure may be achieved by the new processes.

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Estimation of Mechanical Behavior for Particulate Reinforced Composites at Different Temperatures

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1110.32 ◽

2015 ◽

Vol 1110 ◽

pp. 32-35 ◽

Cited By ~ 1

Author(s):

Bo Hwi Seo ◽

Jae Hoon Kim

Keyword(s):

Stress Intensity ◽

Crack Propagation ◽

Mechanical Behavior ◽

Stress Intensity Factors ◽

Viscoelastic Behavior ◽

Rocket Motor ◽

Reinforced Composites ◽

Intensity Factors ◽

Particulate Reinforced Composites ◽

Particulate Reinforced

Particulate reinforced composites show viscoelastic behavior under various loading conditions. It is important to estimate mechanical behavior when this material is used for solid fuel on rocket motor. Cracks can be generated and propagated due to high combustion pressure in the service time. These cracks expand the burning area and lead to excessive combustion. Consequently, the rocket motor can cause malfunction or the performance deteriorated. In this study, edge cracked sheet specimen was used to perform the crack propagation tests. These tests were conducted in the range of temperature from -60°C to 60°C under 2.54 and 12.7 mm/min of strain rates. Based on the results, the stress intensity factors and the crack propagation rests were calculated. The crack resistance curves show the transition that stress intensity factors increases as temperature decrease. Also, fracture surfaces were investigated by scanning electron microscope to determine the fracture behavior under various temperatures.

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Structure images of Si, Ge and Mos2 crystals and some application to radiation damage studies

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010010860x ◽

1978 ◽

Vol 36 (1) ◽

pp. 292-293 ◽

Cited By ~ 1

Author(s):

K. Izui ◽

T. Nishida ◽

S. Furuno ◽

H. Otsu ◽

S. Kuwabara

Keyword(s):

Radiation Damage ◽

Exposure Time ◽

Gaussian Distribution ◽

Intensity Distribution ◽

Chromatic Aberration ◽

Magnetic Lens

Recently we have observed the structure images of silicon in the (110), (111) and (100) projection respectively, and then examined the optimum defocus and thickness ranges for the formation of such images on the basis of calculations of image contrasts using the n-slice theory. The present paper reports the effects of a chromatic aberration and a slight misorientation on the images, and also presents some applications of structure images of Si, Ge and MoS2 to the radiation damage studies.(1) Effect of a chromatic aberration and slight misorientation: There is an inevitable fluctuation in the amount of defocus due to a chromatic aberration originating from the fluctuations both in the energies of electrons and in the magnetic lens current. The actual image is a results of superposition of those fluctuated images during the exposure time. Assuming the Gaussian distribution for defocus, Δf around the optimum defocus value Δf0, the intensity distribution, I(x,y) in the image formed by this fluctuation is given by

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