Rubber, vulcanized or thermoplastic. Determination of tensile stress-strain properties

Keyword(s):  
2013 ◽  
Vol 745-746 ◽  
pp. 219-224
Author(s):  
Li Wei Jing ◽  
Guo Min Zhang ◽  
Jin Cheng Li ◽  
Xin Wu ◽  
Qi Liu

Critical stress/strain is an important parameter to describe the transport property of superconductors under mechanical stress. The critical stress/strain of specified superconductor should be gotten before the superconductor is applied to manufacture devices. Determination of the critical stress/strain of specified superconductor is related to the chosen reduction percentage of the critical current under monotonic mechanical stress. However, in practical applications, superconductor also withstands repetitive mechanical stresses. Therefore, the influence of repetitive mechanical stress on the critical current or N value should be considered when the critical stress/strain of the superconductor is determined. Therefore, in this paper, the electrical transport property of copper reinforced Bi-2223/Ag tapes under both monotonic and repetitive tensile stress was studied theoretically and experimentally. Based on analysis of the change of critical current and N value under monotonic and different repetitive tensile stresses, the critical stress and strain of this superconductor tape were proposed.


2021 ◽  
Vol 2021 (1) ◽  
pp. 92-100
Author(s):  
I. Derevianko ◽  
◽  
K. Avramov ◽  
B. Uspensky ◽  
A. Salenko ◽  
...  

Additive manufacturing is very promising for aerospace engineering and aircraft construction. Using these technologies, light structures with preset strength properties can be made. For lack of tables of the mechanical properties of materials made by additive technologies, any calculation must be accompanied by the experimental determination of their mechanical properties. This paper presents an experimental approach to the determination of the mechanical characteristics of parts printed by FDM technologies. Parts manufactured from polymers by FDM technologies are shown to be orthotropic. Therefore, their elastic properties are described by nine constants: three Young’s moduli, three shear moduli, and three Poisson ratios. A cube is printed for the experimental determination of these constants. Six specimens are cut out from the cube. Three specimens are cut parallel to the cube edges, and the other three are cut at an angle of 45° to them. Each such specimen is manufactured in five pieces. This makes it possible to average the tensile stress–strain diagrams obtained for all the components of the stress tensor. The mechanical properties of the material are determined from these diagrams. The three Young’s moduli and the three Poisson ratios are determined from the three specimen types parallel to the cube edges. The three shear moduli are determined from the specimens cut at an angle of 45° to the cube edges. To determine these constants, tensile stress–strain diagrams are obtained experimentally. A technology is presented for manufacturing specimens on a Stratasys FORTUS 900 MC 3D printer. The mechanical properties of two polymer materials (ULTEM 9085 and PLA) are determined and compared. PLA has higher Young’s moduli and shear moduli and lower Poisson ratios than ULTEM 9085.


1955 ◽  
Vol 4 (6) ◽  
pp. 849-853
Author(s):  
J D TODD ◽  
F A BLAKEY ◽  
F D BERESFORD ◽  
A C BUCK
Keyword(s):  

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