Studying changes of limit deformations and mechanical properties of steels of different structure under single and multiple explosive loading

Author(s):  
O. V. Glibenko ◽  
T. V. Vikhareva ◽  
A. V. Ilyin

The ultimate deformation capacity of stainless high-alloyed austenitic nitrogen-containing steel and low-alloyed chromium-nickel-molybdenum steel up to the moment of failure under single and multiple blast loading in the air has been investigated. The paper presents data on the change in the mechanical properties and structure of these steels as a result of explosive loading to the limit and to the specified level of deformation.

Author(s):  
D.N. Makhina ◽  
◽  
V.N. Denisov ◽  
Yu.S. Perminova ◽  
V.N. Butrim ◽  
...  

2014 ◽  
Vol 30 (6) ◽  
pp. 728-731 ◽  
Author(s):  
Yvette L. Kerkum ◽  
Merel-Anne Brehm ◽  
Annemieke I. Buizer ◽  
Josien C. van den Noort ◽  
Jules G. Becher ◽  
...  

A rigid ventral shelf ankle foot orthosis (AFO) may improve gait in children with spastic cerebral palsy (SCP) whose gait is characterized by excessive knee flexion in stance. However, these AFOs can also impede ankle range of motion (ROM) and thereby inhibit push-off power. A more spring-like AFO can enhance push-off and may potentially reduce walking energy cost. The recent development of an adjustable spring-hinged AFO now allows adjustment of AFO stiffness, enabling tuning toward optimal gait performance. This study aims to quantify the mechanical properties of this spring-hinged AFO for each of its springs and settings. Using an AFO stiffness tester, two AFO hinges and their accompanying springs were measured. The springs showed a stiffness range of 0.01−1.82 N·m·deg−1. The moment-threshold increased with increasing stiffness (1.13–12.1 N·m), while ROM decreased (4.91–16.5°). Energy was returned by all springs (11.5–116.3 J). These results suggest that the two stiffest available springs should improve joint kinematics and enhance push-off in children with SCP walking with excessive knee flexion.


2017 ◽  
Vol 730 ◽  
pp. 548-553
Author(s):  
Jing Ge ◽  
Hao Jiang ◽  
Zhen Yu Sun ◽  
Guo Jun Yu ◽  
Bo Su ◽  
...  

In this paper, we establish the mechanical property analysis of Single-walled Carbon Nanotubes (SWCNTs) modified beam element model based on the molecular structural mechanics method. Then we study the mechanical properties of their radial direction characteristics using the finite element software Abaqus. The model simulated the different bending stiffness with rectangular section beam elements C-C chemical force field. When the graphene curled into arbitrary chirality of SWCNTs spatial structure, the adjacent beam position will change the moment of inertia of the section of the beam. Compared with the original beam element model and the calculation results, we found that the established model largely reduced the overestimate of the original model of mechanical properties on the radial direction of the SWCNTs. At the same time, compared with other methods available in the literature results and the experimental data, the results can be in good agreement.


Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2417 ◽  
Author(s):  
Mingxu Chen ◽  
Xiangyang Guo ◽  
Yan Zheng ◽  
Laibo Li ◽  
Zhen Yan ◽  
...  

Rapid setting and low viscosity of sulphoaluminate cement (SAC) make it difficult to be extruded by 3D printing (3DP) technique. In this study, the effect of tartaric acid (TA) on printability, rheology and mechanical property of 3DP SAC paste is investigated. The experimental results indicate that the setting time, hydration evolution and apparent viscosity of SAC paste can be well controlled by adding a proper amount of TA to satisfy the requirements of 3DP. An excellent structure of SAC paste with the ultimate deformation rate less than 10% can be printed without compromising mechanical strength.


A theory is given of the break-up of the metal case of a cylindrical ring-bomb, in which the lines of fracture perpendicular to the axis of the bomb are predetermined. From the theory an expression is given for the length of the average fragment; this is shown to depend, if certain hypotheses are made, on the radius and velocity of the case at the moment of break-up, and on the mechanical properties of the metal.


2019 ◽  
Vol 2019 (10) ◽  
pp. 1031-1035
Author(s):  
D. N. Makhina ◽  
V. N. Denisov ◽  
Yu. S. Perminova ◽  
V. N. Butrim ◽  
S. A. Nikulin

2019 ◽  
Vol 10 (6) ◽  
pp. 1309-1313
Author(s):  
S. A. Golosienko ◽  
N. A. Minyakin ◽  
V. V. Ryabov ◽  
T. G. Semicheva ◽  
E. I. Khlusova

2012 ◽  
Vol 50 (No. 1) ◽  
pp. 23-27
Author(s):  
J. Fryč ◽  
R. Kukla ◽  
J. Los

Comparison measurements and evaluation of the suitability of three pulsators for sheep milking machines were carried out, i.e. a prototype made by the manufacturer of the milking parlour of the pulsator ratio 50% (50:50) and two hydraulic pulsators of the Danish manufacturer S.A. Christensen (SAC), models Unipuls-2 of the pulsator ratios 50% (50:50) and 60% (60:40). The specified pulsation rate was 2.5/s(150/min). It was found that the pulsator prototype made by the milking parlour manufacturer slowly passed air, whereby the vacuum in pulsation chambers did not attain the maximum value. Fig. 2 illustrates the operation of this pulsator. Both SAC pulsators had better parameters and their pulsograms are plotted in Figs. 3 and 4. Also the measurements of a liner deformation in dependence on the vacuum in the teatcup pulsation chamber were made based on which the moment of a real liner opening, i.e. at the vacuum of 35 kPa was determined. The results obtained by the experiments carried out can be summed up as follows: As the change in pulsation rate does not affect the time of transition phases “a” and “c”, the intervals “b” and “d” are shorter if the pulsation rate is increased. Interval “b”, i.e. a full liner opening, shortens with the rising rate and extends with the increased value of the pulsator ratio. For this reason higher pulsator ratios should be used at very high pulsation rates. The teatcup operation depends on the physical-mechanical properties of the liner used. On the milking unit measured considerable differences in time take place between the interval “b” and the liner full opening due to a relatively high resistance power of the liner to deformation. The pulsator prototype designed by the milking parlour producer revealed as fully unsuitable based on its pulsogram. As far as the time of the liner opening is concerned, its parameters were worse than on both SAC pulsators, however, we cannot indicate it as unsuitable.


1937 ◽  
Vol 10 (4) ◽  
pp. 778-786
Author(s):  
R. Ariano

Abstract The results of tests of the brittleness of ebonite are described. Resilience is influenced chiefly by the moment of inertia of the cross section of the test-specimen, but it seems also to be affected by the form of the specimen. The state of vulcanization has considerable influence on these mechanical properties within the undercured range, but with thorough vulcanization the state of cure plays no appreciable part. Notching of test-specimens is not of great importance. It diminishes the resilience, but when the tests are compared on a basis of equal moments of inertia of the resistant cross sections, this diminution becomes inappreciable in the case of brittle ebonites. On the other hand, the shape of the notch in ebonites containing no loading ingredients does influence the resilience. With V-shaped notches, the depth of the notch and its angle of aperture influence considerably the resilience of this latter type of ebonite, and notches of minimum depth are sufficient to have an appreciable effect.


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