Dynamic properties of concrete in direct tension

2006 ◽  
Vol 36 (7) ◽  
pp. 1371-1378 ◽  
Author(s):  
Dongming Yan ◽  
Gao Lin
2018 ◽  
Vol 183 ◽  
pp. 02035 ◽  
Author(s):  
Anatoly Bragov ◽  
Alexander Konstantinov ◽  
Leopold Kruszka ◽  
Andrey Lomunov ◽  
Andrey Filippov

The combined experimental and theoretical approach was applied to the study of high-speed deformation and fracture of the 1810 stainless steel. The material tests were performed using a split Hopkinson pressure bar to determine dynamic stress-strain curves, strain rate histories, plastic properties and fracture in the strain rate range of 102 ÷ 104 s-1. A scheme has been realized for obtaining a direct tensile load in the SHPB, using a tubular striker and a gas gun of a simple design. The parameters of the Johnson-Cook material model were identified using the experimental results obtained. Using a series of verification experiments under various types of stress-strain state, the degree of reliability of the identified mathematical model of the behavior of the material studied was determined.


2020 ◽  
Vol 82 (4) ◽  
pp. 442-457
Author(s):  
M.E. Gonov

An experimental study of the dynamic properties of fine-grained concrete under tensile and shear stresses has been carried out. A comprehensive study of the dynamic properties of concrete allows obtaining experimental data and constants. These data and constants are needed to equip dynamic strain and fracture models. The system of experiments is based on modifications of the Kolsky method. This system of experiments allows one to determine a wide range of strength and time characteristics of concrete under shock loading. The experimental setup according to the Kolsky method includes a system of measuring rods between which a test sample is installed, a gas gun for accelerating a cylindrical striker, strain gauges, a speed meter, recording and computing equipment with a software package. Conducted dynamic tests of concrete in a wide range of deformation rates (102–104 s–1). In experiments on direct tension and to determine the ultimate tensile stress of fine-grained concrete during splitting, two speed modes are implemented. In tests of shear strength, a modification of the Hopkinson split bar method was used to determine the dynamic shear strength, in which a sample made of the material under study is located in a rigid holder cut at an angle to the sample axis. The pulse recorded in the reference dipstick is used to plot the shear stress in the sample over time. Shear tests were carried out for three speeds. The results of the performed experiments on tensile, splitting and shearing are presented in the form of diagrams of stress versus deformation and stress versus time. The obtained characteristics can be used to equip computational experiments in the study of the strength of concrete structures subjected to dynamic influences.


2021 ◽  
Vol 247 ◽  
pp. 107636
Author(s):  
Zhangyu Wu ◽  
Jinhua Zhang ◽  
Qin Fang ◽  
Hongfa Yu ◽  
Haiyan Ma

Author(s):  
R.F. Stump ◽  
J.R. Pfeiffer ◽  
JC. Seagrave ◽  
D. Huskisson ◽  
J.M. Oliver

In RBL-2H3 rat basophilic leukemia cells, antigen binding to cell surface IgE-receptor complexes stimulates the release of inflammatory mediators and initiates a series of membrane and cytoskeletal events including a transformation of the cell surface from a microvillous to a lamellar topography. It is likely that dynamic properties of the IgE receptor contribute to the activation of these responses. Fewtrell and Metzger have established that limited crosslinking of IgE-receptor complexes is essential to trigger secretion. In addition, Baird and colleagues have reported that antigen binding causes a rapid immobilization of IgE-receptor complexes, and we have demonstrated an apparent increase with time in the affinity of IgE-receptor complexes for antigen.


2006 ◽  
Vol 73 ◽  
pp. 109-119 ◽  
Author(s):  
Chris Stockdale ◽  
Michael Bruno ◽  
Helder Ferreira ◽  
Elisa Garcia-Wilson ◽  
Nicola Wiechens ◽  
...  

In the 30 years since the discovery of the nucleosome, our picture of it has come into sharp focus. The recent high-resolution structures have provided a wealth of insight into the function of the nucleosome, but they are inherently static. Our current knowledge of how nucleosomes can be reconfigured dynamically is at a much earlier stage. Here, recent advances in the understanding of chromatin structure and dynamics are highlighted. The ways in which different modes of nucleosome reconfiguration are likely to influence each other are discussed, and some of the factors likely to regulate the dynamic properties of nucleosomes are considered.


1980 ◽  
Vol 41 (C6) ◽  
pp. C6-404-C6-407 ◽  
Author(s):  
O. Kanert ◽  
R. Küchler ◽  
M. Mali
Keyword(s):  

1990 ◽  
Vol 51 (C1) ◽  
pp. C1-381-C1-390 ◽  
Author(s):  
M. FRIESEL ◽  
I. MANNA ◽  
W. GUST

2020 ◽  
Vol 7 (3) ◽  
pp. 23-28
Author(s):  
EZIZ SARVAN SHIRVAN ◽  

This paper discusses the kinematic characteristics of lapping process and the main parameters of the process. It was determined that the influencing degree of technological parameters to the forming surface and processes. It was projected the construction of the lapping head for processing of internal cylindrical surfaces, scheme of the lapping operation and graphic description of the forces influencing. The relationships between the axial, radial and tangential cutting forces and the effect of the combined force thereof are determined in order to ensure the necessary surface pressure. During the analysis geometric and mathematical relationships were obtained. The extracted analytical expressions can be realized by further experimental researches and can be used in engineering calculations of technological parameters of processing by lapping. Angular velocity, friction force, linear velocity, also the length of the tactile curve and the radius of the part can be considered the main kinematic and dynamic parameters of the process that the formation of the surface, also the course of the process depends on these parameters. Depending on the kinematic parameters, the wear nature of the tool changes and this changes the linear and angular velocities, which have a significant impact on the accuracy, quality and productivity of processing. When examining the technological capabilities of the process, the nature of the movement between the part and the grinding tool, also changes in cutting speed are often considered as a main factor. Analytical expressions were obtained to determine the main parameters of the process, taking into account the kinematic characteristics of the friction process. These expressions can be used in engineering calculations and allow to determine the optimal values of the processing mode. In order to obtain the required micrometric surface cleanliness and measurement accuracy, correlation relationships were established between the main parameters of the process, equations of the equilibrium system of shear forces were compiled and analytical expressions were obtained based on the analysis of kinematic and dynamic properties of the system.


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