scholarly journals Mechanical Behavior Of Energetic Materials During High Acceleration

2002 ◽  
Vol 759 ◽  
Author(s):  
Y. Lanzerotti ◽  
J. Sharma
Keyword(s):  
Tensile Strength ◽  
Mechanical Behavior ◽  
Energetic Materials ◽  
Type Ii ◽  
High Acceleration

ABSTRACTThe mechanical behavior of explosives subjected to high acceleration has been studied in an ultracentrifuge at –10°C and 25°C. Melt-cast TNAZ and pressed TNAZ, LX-14, Composition A3 Type II, PAX-2A, and PAX-3 have been studied. Failure occurs when the shear or tensile strength of the explosive is exceeded. The fracture acceleration of melt-cast TNAZ is greater than that of pressed TNAZ at –10°C and 25°C. The fracture acceleration of PAX-3 is greater than that of Composition A3 Type II at –10°C and 25°C. The fracture acceleration of melt-cast TNAZ and pressed TNAZ at –10°C is about 10% less than at 25°C. The fracture acceleration of PAX-3 at –10°C is about 2.6 times that at 25°C. The fracture acceleration of Composition A3 Type II at –10°C is about 1.7 times that at 25°C.

AFM Studies of Fracture Surfaces of Composition B Energetic Materials

2001 ◽  
Vol 705 ◽  
Author(s):  
Y. D. Lanzerotti ◽  
J. Sharma
Keyword(s):  
Atomic Force Microscopy ◽  
Tensile Strength ◽  
Fracture Surface ◽  
Surface Structure ◽  
Energetic Materials ◽  
Mechanical Failure ◽  
Force Microscopy ◽  
Atomic Force ◽  
High Acceleration ◽  
Columnar Grains

AbstractThe characteristics of TNT (trinitrotoluene) crystals in Composition B have been studied using atomic force microscopy (AFM). The size of TNT crystals has been examined by analyzing the surface structure that is exhibited after mechanical failure of the Composition B. The mechanical failure occurs when the material is subjected to high acceleration (high g)inan ultracentrifuge and. the shear or tensile strength is exceeded. AFM examination of the topography of the Composition B fracture surface reveals fracture across columnar grains of the TNT. The width of the columnar TNT grains ranges in size from ~ 1 μm to~2 μm. Their height ranges in size from ~ 50 nm to ~ 300 nm.

Mechanical Behavior of Energetic Materials During High Acceleration in An Ultracentrifuge

1994 ◽  
Vol 362 ◽  
Author(s):  
M. Yvonne D. Lanzerotti ◽  
J. Sharma
Keyword(s):  
Mechanical Behavior ◽  
Surface Area ◽  
Energetic Materials ◽  
Area Ratio ◽  
Crystal Defects ◽  
Surface Area Ratio ◽  
High Acceleration ◽  
New Information ◽  
Binding Surface ◽  
Effective Additive

AbstractThe mechanical behavior of explosives subjected to high acceleration (high g) has been studied in an ultracentrifuge. The experiments reported here reveal new information on the mechanical behavior of such materials and the influence of grain size on the fracture process. Through measurement and analysis of fracture surfaces, we have found that predominately intergranular failure occurs when the shear or tensile strength of the explosive is exceeded. We have found that the mechanical strength of melt-cast polycrystalline TNT varies inversely with crystal size. That is, if the sample consists of large, homogeneous crystals, these are found to separate from the sample at lower g-levels due to the larger mass-to-binding surface area ratio of the crystals. Conversely, smaller original crystallites are found to separate at higher g-levets due to the smaller mass-to-binding surface area ratio. Our results show that single crystals of TNT fracture under a higher g-level at crystal defects. We have also found that the fracture acceleration of Octol decreases with increasing percent TNT and decreasing percent HMX. Hexanitrostilbene (HNS) has been shown by other investigators to be an effective additive to prevent growth of large TNT grains. We have found that the fracture acceleration increases when HNS is added to Octol.

Mechanical Behavior for some Cobalt Alloys

2015 ◽  
Vol 1114 ◽  
pp. 9-12
Author(s):  
Alexandru Ghiban ◽  
Brandusa Ghiban ◽  
Cristina Maria Borţun ◽  
Nicolae Serban ◽  
Mihai Buzatu
Keyword(s):  
Tensile Strength ◽  
Chemical Composition ◽  
Mechanical Behavior ◽  
Mechanical Characteristics ◽  
Fractographic Analysis ◽  
Cobalt Alloys ◽  
Dental Alloys ◽  
Bending Tests ◽  
Longitudinal Modulus

Four compositions of some usually commercial dental alloys were investigated in order to determine the mechanical characteristics and fractographic analysis of tensile and bending tests surfaces. A correlation between chemical composition (either molybdenum or molybdenum and chromium contents) and mechanical characteristics (longitudinal modulus, tensile strength and elongation) were finally done.

Crystal Growth of Energetic Materials during High Acceleration using an Ultracentrifuge

1994 ◽  
pp. 181-184
Author(s):  
M. Y. D. Lanzerotti ◽  
J. Autera ◽  
J. Pinto ◽  
J. Sharma
Keyword(s):  
Crystal Growth ◽  
Energetic Materials ◽  
High Acceleration

scholarly journals A numerical and experimental study on the tensile behavior of plasma shocked granite under dynamic loading

2017 ◽  
Vol 50 (2) ◽  
pp. 41-62
Author(s):  
Ahmad Mardoukhi ◽  
Timo Saksala ◽  
Mikko Hokka ◽  
Veli-Tapani Kuokkala
Keyword(s):  
Experimental Study ◽  
Tensile Strength ◽  
Mechanical Behavior ◽  
Thermal Shock ◽  
Dynamic Loading ◽  
Split Hopkinson Pressure Bar ◽  
Tensile Behavior ◽  
Brazilian Disc ◽  
Brazilian Disc Test ◽  
Plasma Shock

This paper presents a numerical and experimental study on the mechanical behavior of plasma shocked rock. The dynamic tensile behavior of plasma shock treated Balmoral Red granite was studied under dynamic loading using the Brazilian disc test and the Split Hopkinson Pressure Bar device. Different heat shocks were produced on the Brazilian disc samples by moving the plasma gun over the sample at different speeds. Microscopy clearly showed that as the duration of the thermal shock increases, the number of the surface cracks and their complexity increases (quantified here as the fractal dimension of the crack patterns) and the area of the damaged surface grows larger as well. At the highest thermal shock duration of 0.80 seconds the tensile strength of the Brazilian disc sample drops by approximately 20%. In the numerical simulations of the dynamic Brazilian disc test, this decrease in tensile strength was reproduced by modeling the plasma shock induced damage using the embedded discontinuity finite element method. The damage caused by the plasma shock was modeled by two methods, namely by pre-embedded discontinuity populations with zero strength and by assuming that the rock strength is lowered and conform to the Weibull distribution. This paper presents a quantitative assessment of the effects of the heat shock, the surface microstructure and mechanical behavior of the studied rock, and a promising numerical model to account for the pre-existing crack distributions in a rock material.

Mechanical Properties of P34HB/PLA Binary Blendsafter Thermal-Oxidative and Hydrothermal Aging

2013 ◽  
Vol 647 ◽  
pp. 798-801 ◽  
Author(s):  
Wen Can Xi ◽  
Hong Mei Kang ◽  
Hua Li ◽  
He Zhou Liu ◽  
Wei Jie Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Lactic Acid ◽  
Mechanical Behavior ◽  
Poly Lactic Acid ◽  
Hydrothermal Aging ◽  
Weight Percentage ◽  
Lower Ratio

Binary blendscomposed of polyhrdroxyalkanoates (P34HB) and poly(lactic acid) (PLA) with various P34HB weight percentage were preparedby extrusion and compressing molding.Both the thermo-oxidative agingat 80°Cand the hydrothermal aging at 80°C with 80% humidity were performed for 300 h for the P34HB/PLA blends respectively.The mechanical properties of tensile strength and elongation-at-breakrevealed that P34HB/PLA blends possessedthe balanced mechanical properties between P34HB and PLA,theblends with higher ratio of P34HBshowed thedeteriorative mechanical behavior in the aging environment faster than thoseblends with lower ratio of P34HB.

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