Study on the Relationship between Microscopic Structure and Mechanical Properties of HTPB Propellant

2010 ◽  
Vol 152-153 ◽  
pp. 1151-1155 ◽  
Author(s):  
Xu Chang Li ◽  
Jian Jiao ◽  
Jun Yan Yao ◽  
Liang Wang

By means of a tensile instrument and SEM, the mechanical property parameters of HTPB propellant test samples with different formulas were tested, and their microscopic fracture cross section patterns were observed. Take advantage of these testing results, the relationship between microscopic structure and mechanical properties of HTPB propellant was studied. The results show that the mechanical properties of a propellant are closely related to its microscpic structure state. The structural integrity of propellant is mainly influenced by the bond effect of the interface between binder and solid particles, solid particle’s shape, size and its distribution, the content of binder matrix, etc. These factors have important effects on the mechanical properties of propellant.

2017 ◽  
Vol 741 ◽  
pp. 7-12
Author(s):  
Shota Okuno ◽  
Qiang Yu ◽  
Yusuke Nakata

Recently, sintering joint using Ag-nanohas been attracting attention as a new joint method to replace the solder. However, the joint layer would contain a lot of voids after sintering processes. Since the voids affect mechanical property, the proper sintering conditions have to be selected in order to reduce these voids. In this research, the authors focus on the effect of pressure conditions at sintering process. Then, by creating FEM models including voids from cross section image of the joint layer and carrying out tensile analysis, the mechanical property of the joint layer has been acquired. Using this approach, the influence of pressure conditions on the mechanical properties is revealed.


2009 ◽  
Vol 610-613 ◽  
pp. 796-800 ◽  
Author(s):  
Jian Peng ◽  
Cheng Meng Song ◽  
Ya Zhong Zhao ◽  
Fu Sheng Pan

The mechanical properties and microstructure of the as-extruded ZM21 magnesium alloy and its modified alloy ZME210 with addition of 0.35wt% cerium were investigated with different extrusion ratios from 14 to 182 by using mechanical property test, microscopic structure quantitative analysis, SEM observation and energy spectrum analysis. The results showed that both ZM21 and ZME210 had an extrusion ratio limit for grain refining, and the grains were found to be finer with higher extrusion ratio when the ratio was not higher than the limit value. The extrusion ratio limit for the best effect for grain refining of ZME210 is lower than that of ZM21. It was found that the Ce can refine the grains effectively after hot extrusion with different extrusion ratios. The effects of Ce on the microstructure and mechanical properties were analyzed.


2018 ◽  
Vol 765 ◽  
pp. 54-59 ◽  
Author(s):  
Xiang Dong Chen ◽  
Xin Long Chang ◽  
You Hong Zhang ◽  
Bin Wang ◽  
Qing Zhang ◽  
...  

To study the low temperature effects of tensile mechanical properties on Hydroxyl-terminated polybutadiene (HTPB) propellant, a quasi-static mechanical experiment was conducted. The results show that tensile mechanical parameters are closely related to strain rate and low temperature. With the decrease of temperature and increase of strain rate, the modulus and tensile strength of HTPB propellant increase obviously. Based on the time-temperature equivalence principle (TTEP), the master curves of tensile strength and initial modulus for HTPB propellant were obtained, which can facilitate the structural integrity analysis of the propellant. The damage of propellant is matrix tearing and dewetting between the filled particles and matrix.


2012 ◽  
Vol 184-185 ◽  
pp. 222-226
Author(s):  
Fan Fen Peng ◽  
Shu Xian Zheng ◽  
Jia Li

The relationship between the porosity and the mechanical property was still a bottle-neck in bone tissue engineering scaffold. Porosity increasing may reduce the scaffold strength. In order to solve the contradiction, the idea of enhancing the mechanical properties by controlling the scaffold porosity was proposed in this paper. Using reverse engineering technology, 5 different porosity cranium scaffolds were first established. Their FE models were built through FE surface preprocessing and volume fitted meshing. According to results of static analysis, the displacements and stresses of the 5 porosity scaffolds were compared and discussed and it indicated that the 36% porosity bionic scaffold have good porous level and mechanical properties.


2014 ◽  
Vol 1049-1050 ◽  
pp. 325-334
Author(s):  
Yong Wang ◽  
De Hua Deng ◽  
Qiang Yuan ◽  
Jian Wei Peng ◽  
Lei Fang

This paper deals with the effect of calcium leaching on the microstructure and rupture strength of cement asphalt (CA) mortar. It is conducted by an accelerated experiment method with species obtained from construction site. Results show that the leaching process mainly contains a total leaching of CaOH2 (CH) and some other cement hydrations. The leaching is proved by the “portlandite dissolution front” on the cross-section of species using a reagent of phenolphthalein. As time goes, the species are continually leached, and then the loss of mass and porosity ratio are obviously increased. Fick’s law can describe the relationship between leaching depth and time very well. The loss of mass and increasing of porosity ratio respond to the shrinking of mechanical properties of CA mortar.


2015 ◽  
Vol 817 ◽  
pp. 173-179 ◽  
Author(s):  
Xue Kong ◽  
Bi Cheng Yang ◽  
Zhi Feng Zhang ◽  
Jun Xu

The effect of reheating process on the microstructure and mechanical property of A390 aluminum alloy and its evolution mechanism was studied. During reheating process, the microstructure of A390 ingots changed greatly, the microstructure ofα-Al particles changed from dendrite to spherical. As the reheating temperature increased primary Si and eutectic Si gradually grew up and spheroidized while the mechanical properties got the maximum value as the ingot reheating to 540°C. The relationship the between reheating power and microstructure was built. Improving reheating power can restrain the growth of grains, but if the reheating power was too high, the microstructure becomes non-uniform. It has been found that reheating of A390 aluminum alloy experiences two processes of grain combination and Ostwald growing.


1996 ◽  
Vol 436 ◽  
Author(s):  
S. V. Hainsworth ◽  
T. F. Page

AbstractOne of the critical aspects of assessing the properties of coated systems is the prospect of being able to measure the properties of the coating in isolation of the substrate. This has led to an increase in the use of continuously-recording indentation techniques (or nanoindentation techniques) for assessing the mechanical properties of coated systems since they can be used to measure the materials response to contact deformation at a scale relevant to the coating thickness. This paper presents the results of a new method for analysing the nanoindentation loading curves for coated systems. The analysis of the loading curve uses the relationship P = Kmδ2 which describes the indenter displacement, δ, in terms of the applied load P. For each material, Km can be predicted from its modulus E and hardness H. One result is that if either of E or H is known, then the other may be calculated from the experimental loading curve. Further, the method has the potential to differentiate between the responses of the coating only, the coating and substrate in combination, and that dominated by the substrate once the load has become sufficient for cracking of the coating such that it no longer plays a significant role in supporting the applied load. In many cases, careful analysis of the loading curves allows the displacement ranges associated with these regimes to be identified. This is shown to be a powerful experimental tool for the interpretation of the mechanical properties of coated systems.


2011 ◽  
Vol 411 ◽  
pp. 518-522
Author(s):  
Shao Hui Tian ◽  
Zhi Yi Hu ◽  
Hong Shu Chen

Under the circumstance of the same parameters as fabric density, yarn type and so on, different fancy openwork could be weaved respectively in which the fabric mesh layout are various. Then in order to get the fabric pore size distribution parameters under the best mechanical strength, the different fancy openwork should be applied in tensile and tear strength tests, which can contribute to analyze the relationship between mesh fabric structure and its mechanical property.


2013 ◽  
Vol 539 ◽  
pp. 178-183 ◽  
Author(s):  
Zheng Wu Jiang ◽  
Zi Long Deng ◽  
Nan Zhang

In this paper, pore structures and their changes of ordinary-strength concrete and high-strength concrete at different curing ages of 3, 28, 90 days were studied using thermoporometry, and the results were compared with those from MIP and NAD. The relationship between micro pores and porosity of concrete and its macroscopic properties was also studied. The results indicate that, compared to MIP, thermoporometry can characterize the features of pores with the diameter smaller than 100 nm in concrete accurately. The differences of macroscopic mechanical properties of concretes can be explained using the changes of their pore size distribution. After curing age of 28 days, the amount of pores with the diameter higher than 20 nm in high strength concrete changes little, but it decreases gradually in ordinary strength concrete. And pores with diameter smaller than 20 nm in concrete have little influence on the macroscopic mechanical property of concrete.


Author(s):  
K. Poorhaydari ◽  
B. M. Patchett ◽  
D. G. Ivey

The weld thermal cycle in microalloyed pipeline and structural steels results in significant changes in microstructure and, consequently, mechanical properties of the weld heat-affected zone (HAZ). To have better control of the properties of the HAZ, knowledge of these changes and correlation with mechanical property variations is required. The first step in achieving this is to construct a methodology to examine different regions of the HAZ thoroughly, so that important characteristics such as grain size, microstructure, precipitate type and distribution, and mechanical properties are determined. The next step would be using this methodology to examine different regions of the HAZ under different welding conditions (the most important of which is heat input) and therefore to understand the effects of the welding process. In this paper, a methodology for studying HAZ microstructure/property relationships is demonstrated for a Grade 100 microalloyed steel welded autogenously (no filler metal). Microhardness measurements are used to assess the mechanical property variation across the HAZ. Optical microscopy (OM) and transmission electron microscopy (TEM) are used for grain structure examination and precipitate analysis. The relationship between microstructure and mechanical properties, with emphasis on precipitate reactions, is presented for different regions of the HAZ.


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