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.

Validating the New Equivalent Static Design Method of Spacecraft Structures in Random Vibration by Test

2013 ◽  
Vol 419 ◽  
pp. 464-469
Author(s):  
Yu Mei Zhang ◽  
Zeng Yao Han ◽  
Si Dian Shi ◽  
Li Meng Tan
Keyword(s):  
Yield Strength ◽  
Time Domain ◽  
Random Vibration ◽  
Static Load ◽  
Design Method ◽  
Structure Design ◽  
Equivalent Static Load ◽  
Static Yield ◽  
Dynamic Yield Strength ◽  
Dynamic Yield

Random vibration is one of dynamic environments of spacecraft during launch. In engineering, design load was usually equivalent static load based on acceleration. A new equivalent static load based on strain or stress was presented by the writer. To validate the new equivalent static design method, random vibration test was designed including test article and test specification, and signal processing was in time domain; static test was designed to compare static yield strength and dynamic yield strength, and dynamic yield strength was 50% -80% higher than static yield strength; measured data in time domain was analyzed , and the equivalent static design of strain based on first passage model can be used to spacecraft structure design. And it will decrease the mass of spacecraft structure obviously.

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.

scholarly journals Application of classification neural networks for identification of damage stages of degraded low alloy steel based on acoustic emission data analysis

2020 ◽  
Vol 20 (4) ◽  
Author(s):  
Joanna Krajewska-Śpiewak ◽  
Igor Lasota ◽  
Barbara Kozub
Keyword(s):  
Neural Networks ◽  
Acoustic Emission ◽  
Alloy Steel ◽  
Learning Algorithm ◽  
Structural Condition ◽  
Oil Refinery ◽  
Low Alloy Steel ◽  
Emission Data ◽  
Methodology Development ◽  
Static Tensile

Abstract The paper presents the influence of low alloy steel degradation on the acoustic emission (AE) generated during static tension of notched specimen. The material was cut from a technological pipeline long-term operated in the oil refinery industry. Comparative analysis of AE activity generated by damage process of degraded and new material has been carried out. The different AE parameters were used to detect different stages of fracture process of low alloy steel under quasi-static tensile test. Neural networks with three layers were created with Broyden–Fletcher–Goldfarb–Shanno learning algorithm for a database analysis. The different AE parameters were included in the input layer. Classification neural networks were created in order to determine the stages of material degradation. The results obtained from the carried out studies will be used as the basis for new methodology development of the assessment of the structural condition of in-service equipment.

Study of Low Carbon Low Alloy Steel Annealing Process Parameters Optimization

2013 ◽  
Vol 631-632 ◽  
pp. 649-659
Author(s):  
Mao Yu Zhao ◽  
Qian Wang Chen
Keyword(s):  
Yield Strength ◽  
Alloy Steel ◽  
Process Parameters ◽  
Orthogonal Experiment ◽  
Annealing Process ◽  
Parameters Optimization ◽  
Grey Theory ◽  
Low Carbon ◽  
Low Alloy Steel ◽  
Sem Images

A suitable match of annealing process parameters is critical for obtaining the fine microstructure of material. Low carbon low alloy steel (20CrMnTi) was heated for various durations near Ac temperature to achieve fine pearlite and ferrite grains. Annealing temperature and time were used as independent variables, and material property data were acquired by orthogonal experiment under intercritical annealing followed by subcritical annealing process (IASAP). The weights of plasticity (hardness, yield strength, section shrinkage, and elongation) of annealing material were calculated by analytic hierarchy process, and then the process parameters were optimized by using the grey theory system. The results observed by SEM images show that the optimized material microstructure consists of refining and distributing uniformly ferrite-pearlite grains, and smaller lamellar cementites. Morphologies on tension fracture surface of the optimized material indicates that the numbers of dimple fracture show more finer toughness obviously comparing with other annealing materials. Moreover, the yield strength value of the optimized material decreases apparently measured by tensile test. Thus, the new optimized strategy is accurate and feasible.

Mechanical Properties of a Medium Carbon Low Alloy Steel Processed by Two Step Austempering Process

2010 ◽  
Vol 638-642 ◽  
pp. 3453-3458 ◽  
Author(s):  
Susil K. Putatunda ◽  
Abhijit Deokar ◽  
Gowtham Bingi
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Yield Strength ◽  
Alloy Steel ◽  
High Yield ◽  
Bainitic Steel ◽  
Low Alloy Steel ◽  
High Yield Strength ◽  
Medium Carbon

A new bainitic steel with a combination of exceptionally high yield strength and fracture toughness has been developed. This steel has been synthesized by austempering a medium carbon low alloy steel by a novel two-step austempering process. The influence of this two-step austempering on the microstructure and the mechanical properties of this new steel have been examined.

Sign in / Sign up

Export Citation Format

Share Document