Monitoring of the uniformity of the thermal linear expansion coefficient of large-size optical components

2009 ◽  
Vol 52 (7) ◽  
pp. 755-760
Author(s):  
T. A. Kompan ◽  
A. A. Sharov
2012 ◽  
Vol 253-255 ◽  
pp. 529-532
Author(s):  
Jian Jun Yan ◽  
Shi Hua Zhou ◽  
Shang Shi Peng

The crack resistance of concrete with crushed basalt aggregate was studied. Compared with the limestone concrete, the basalt concrete has larger drying shrinkage and autogenous volume deformation. The linear expansion coefficient of basalt concrete is 1.3×10-6 /°C larger than that of limestone concrete, and it has additional temperature deformation of 24.1×10-6. According to the analysis on temperature-stress of concrete, the cracking temperature of basalt concrete is 8.9°C higher than that of limestone concrete, and the crack resistance of basalt concrete is unfavorable.


2020 ◽  
Vol 3 (1) ◽  
pp. 1-12
Author(s):  
Tatiana N. Ivanova ◽  
Witold Biały ◽  
Jiři Fries ◽  
Victor Nordin

AbstractThe deformation of a part occurring in the process of grinding directly influences its exploitation and quality parameters. The instability of shape and size, which occurs due to an imbalance of residual stress, can be the one of the major causes of deformation of a part. The decrease in stress slows down the deformation process. Considering the regularities of heat source intensity dependence on the grinding modes, it can be asserted that with increasing grinding depth and grinding wheel hardness, the value increases and it decreases with a growth in a speed of the part and the use of cooling. The higher the heat removal is and the better lubricant properties of the liquid are, the more significant the decrease in is. Changing these values allows regulation of the residual stresses. As a result of the research on determination of deformations, it is recommended to reduce thermal deformations by considering the geometric size of a plate to be machined, linear expansion coefficient of plate material and an allowance for nonflatness from thermal deformations. The value of nonflatness from thermal deformations is directly proportional to linear expansion coefficient of plate material and its square overall dimensions. At the same time, the value of nonflatness is inversely proportional to the plate thickness.


2018 ◽  
Vol 47 (7) ◽  
pp. 706005
Author(s):  
布音嘎日迪 Bu Yingaridi ◽  
仲维丹 Zhong Weidan ◽  
甄佳奇 Zhen Jiaqi ◽  
高亚臣 Gao Yachen ◽  
刘 勇 Liu Yong ◽  
...  

2010 ◽  
Vol 156-157 ◽  
pp. 1251-1255 ◽  
Author(s):  
Zhi Hua Chen ◽  
Guo Jun Sun ◽  
Zhan Sheng Liu

Cable is the key component in the prestressed steel structure. In order to study the effect of cable elastic modulus and expansion coefficient on the prestressed steel structure, Suspendome of Tianbao Center was taken as the research object and APDL language is applied to write a corresponding program, thereby carrying out analysis to the model; The results indicate that the change of cable expansion coefficient and cable elastic modulus have a different effect on the performance of the suspendome: at high temperature, the effect of the expansion coefficient of hoop cable and radial cable is larger on the maximum displacement; at low temperature, the effect of the elastic modulus of hoop cable is larger on the support constrained force. Therefore, it is necessary to give precise linear expansion coefficient and elastic modulus for different cables.


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