Measurement of Dynamic Stress and Strain in Tensile Test Specimens

1944 ◽  
Vol 11 (2) ◽  
pp. A65-A71
Author(s):  
R. O. Fehr ◽  
E. R. Parker ◽  
D. J. DeMicheal
Keyword(s):  
Tensile Strength ◽  
Yield Strength ◽  
Testing Machine ◽  
Impact Testing ◽  
High Rate ◽  
Stress And Strain ◽  
Dynamic Tensile Strength ◽  
Dynamic Yield Strength ◽  
Dynamic Yield ◽  
Cold Rolled

Abstract In the investigation detailed in this paper, the tensile strength, the yield strength, and the breakage energy of test specimens (cold-rolled steel and dural) were measured while the specimens were being broken by a force applied at a high rate of speed in a commercial high-velocity impact-testing machine. The dynamic tensile strength, the dynamic yield strength and the dynamic breakage energy were found to be higher than the static values up to the maximum impact velocities of these tests (100 fps). The paper contains: (1) A presentation of some results of these tests. (2) A description of the technique used. (3) A description of the analysis used.

scholarly journals Calibration of Discrete-Element-Method Parameters for Cohesive Materials Using Dynamic-Yield-Strength and Shear-Cell Experiments

Processes ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 278 ◽  
Author(s):  
Subhodh Karkala ◽  
Nathan Davis ◽  
Carl Wassgren ◽  
Yanxiang Shi ◽  
Xue Liu ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Surface Energy ◽  
Yield Strength ◽  
Discrete Element Method ◽  
Critical State ◽  
Discrete Element ◽  
Shear Cell ◽  
Dynamic Yield Strength ◽  
Dynamic Yield ◽  
Friction Parameters

This study tested the effectiveness of using dynamic yield strength (DYS) and shear-cell experiments to calibrate the following discrete-element-method (DEM) parameters: surface energy, and the coefficients of sliding and rolling friction. These experiments were carried out on cohesive granules, and DEM models were developed for these experiment setups using the JKR cohesion contact model. Parameter-sensitivity analysis on the DYS model showed that the DYS results in the simulations were highly sensitive to surface energy and were also impacted by the values of the two friction coefficients. These results indicated that the DYS model could be used to calibrate the surface energy parameter once the friction coefficients were fixed. Shear-cell sensitivity analysis study found that the influence of surface energy on the critical-state shear value cannot be neglected. It was inferred that the shear-cell model has to be used together with the DYS model to identify the right set of friction parameters. Next, surface energy was calibrated using DYS simulations for a chosen set of friction parameters. Calibrations were successfully conducted for simulations involving experimentally sized particles, scaled-up particles, a different shear modulus, and a different set of friction parameters. In all these cases, the simulation DYS results were found to be linearly correlated with surface energy and were within 5% of the experimental DYS result. Shear-cell simulations were then used to compare calibrated surface-energy values for the scaled-up particles with the experimentally sized particles. Both the simulations resulted in similar critical-state shear values. Finally, it was demonstrated that a combination of DYS and shear-cell simulations could be used to compare two sets of friction parameters and their corresponding calibrated surface energy values to identify the set of parameters that better represent the flow behavior demonstrated by the experimental system.

Evaluating the Strength of the Friction Stir Welded Joints at Various Rotational Speeds

2013 ◽  
Vol 446-447 ◽  
pp. 312-315
Author(s):  
Ramaraju Ramgopal Varma ◽  
Abdullah Bin Ibrahim ◽  
B. Ravinder Reddy
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Friction Stir Welding ◽  
Yield Strength ◽  
Welded Joints ◽  
Rotational Speed ◽  
Testing Machine ◽  
Friction Stir ◽  
Universal Testing ◽  
Welding Technique

The present research paper aims in evaluating the strength of the welded AA6351 alloy plates of 6 mm thick by using friction stir welding technique at different rotational speeds The applied welding technique is capable of achieving the mechanical properties of the alloy close to that of the original alloy. In the present investigation, the speeds of the spindle were varied from 1100 rpm to 1500 rpm with a constant transverse speed of 20 mm/min. The tensile strength of the joints is determined by an universal testing machine. The results from the present investigation show that the values of the yield strength were very much closer to the values of the AA6351Alloy prior to welding. It has been found from the experiments that the strength of the joints increases with the increase in the rotational speed; however, the same is decreasing after achieving certain speed.

The Dynamic Yield Strength of Steel at an Intermediate Rate of Loading

1948 ◽  
Vol 159 (1) ◽  
pp. 11-23 ◽  
Author(s):  
A. F. C. Brown ◽  
R. Edmonds
Keyword(s):  
Yield Strength ◽  
Alloy Steel ◽  
Underwater Explosion ◽  
Low Alloy Steel ◽  
Heat Treated ◽  
Static Tensile ◽  
Static Yield ◽  
Dynamic Yield Strength ◽  
Dynamic Yield ◽  
Rate Of Loading

A comparison has been made between the dynamic and static tensile yield strengths of eight steels varying from mild steel to a heat-treated low-alloy steel, the rate of loading in the dynamic tests being such as would occur in a ship under the action of an underwater explosion. The dynamic yield strength of the steels with low static strength was 20–30 per cent greater than their static yield strength but, for the stronger steels, the increase was less, being negligible in the case of the heat-treated low-alloy steel. This result conforms with the findings of other investigators, and shows that any increase in strength under the dynamic loading considered is too small to be of importance in design.

Effects of Heat Treatment Process on Mechanical Properties of X70 Grade Pipeline Steel Bends

2015 ◽  
Vol 727-728 ◽  
pp. 322-326 ◽  
Author(s):  
Shi Lu Zhao ◽  
Zhen Zhang ◽  
Lian Chong Qu ◽  
Jun Zhang ◽  
Jian Ming Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Yield Strength ◽  
Thermal Insulation ◽  
Treatment Process ◽  
Pipeline Steel ◽  
Impact Testing ◽  
Air Cooling ◽  
Heat Treatment Process

Effects of heat treatment process of quenching and tempering under different temperature conditions on mechanical properties of X70 grade pipeline steel bends were studied. Brinell hardness, yield strength, tensile strength, elongation and impact absorbing energy of the bends were tested by using hardness tester, cupping machine and impact testing machine, respectively. It shows that the best heat treatment process of the X70 grade pipeline steel bends is quenching at 890 °Cand thermal insulation for 26 min then water cooling followed by tempering at 590 °C and thermal insulation for 60 min then air cooling. Furthermore, the resulting hardness, yield strength, tensile strength, yield ratio, elongation and impact absorbing energy reach HB230, 595 MPa, 725 MPa, 0.82, 28% and 300 J respectively, which has excellent comprehensive mechanical properties.

Experimental Researches on Relation between Martens Hardness and Traditional Mechanical Properties

2012 ◽  
Vol 189 ◽  
pp. 205-209 ◽  
Author(s):  
Wang Yang ◽  
Jing Wang ◽  
Yi Liang Zhang ◽  
Yang Liu
Keyword(s):  
Tensile Strength ◽  
Regression Analysis ◽  
Linear Regression ◽  
Yield Strength ◽  
Vickers Hardness ◽  
Linear Regression Analysis ◽  
Testing Machine ◽  
Mathematic Model ◽  
Rockwell Hardness ◽  
Martens Hardness

For finding the relation between Martens hardness and Vickers hardness, Rockwell hardness, tensile strength, yield strength, research are done on carbon alloy steel by experiment, linear regression analysis and derivation of equation .Martens hardness, Vickers hardness and Rockwell hardness of 30 samples which contains 3 material and 10 hardness levels are tested by ZHU 2.5 hardness tester. On the basis of 180 groups of data obtained and analyzed from instrumented indentation experiments, mathematic model between Martens hardness and Vickers hardness is established, by linear regression analysis. And mathematic model between Martens hardness and Rockwell hardness, tensile strength, yield strength is established on that basis. By means of comparing the value calculated by the mathematic model and obtained from tensile test using Electronic universal testing machine, the accuracy of the mathematic model is verified. The result show that the relative error of the four mathematics models which established in this test is below 5%, and the four mathematics models can be applied to the practical engineering application.

scholarly journals Temperature dependence of dynamic yield strength and spall strength for LY12 aluminum alloy under shock loading

2006 ◽  
Vol 55 (8) ◽  
pp. 4202
Author(s):  
Wang Yong-Gang ◽  
Chen Deng-Ping ◽  
He Hong-Liang ◽  
Wang Li-Li ◽  
Jing Fu-Qian
Keyword(s):  
Aluminum Alloy ◽  
Yield Strength ◽  
Temperature Dependence ◽  
Shock Loading ◽  
Spall Strength ◽  
Dynamic Yield Strength ◽  
Dynamic Yield
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