The yield behaviour of mild steel in dynamic compression

1956 ◽  
Vol 236 (1204) ◽  
pp. 24-40 ◽  
Keyword(s):  
Mild Steel ◽  
Impact Load ◽  
Dynamic Compression ◽  
Steel Specimen ◽  
Dynamic Strain ◽  
Compression Tests ◽  
Static Compression ◽  
Yield Phenomena ◽  
Stress Strain Relation ◽  
Yield Behaviour

Results of earlier investigations of dynamic yield phenomena are reviewed. Experiments are described in which a mild steel specimen is subjected a to compressive impact load causing yield in 25 to 30 μs . Stress-time curves are obtained and analyzed in terms of wave propagation, and a dynamic stress-strain relation is derived. Micrographs of specimens after dynamic yielding show that coarse slip does not occur, though there is some evidence of fine slip and grain boundary movement. Static compression tests on dynamically yielded specimens show that less hardening is caused by dynamic strain than by the same amount of static strain. The results are discussed in terms of dislocation theory.

Evaluation of Belleville Springs and Damping Through Static Cyclic Loading “Hysteresis” for pVARD Optimization: Part-I

2021 ◽  
Author(s):  
Abdelsalam Abugharara ◽  
Stephen Butt
Keyword(s):  
Data Analysis ◽  
Cyclic Loading ◽  
Dynamic Compression ◽  
Range Data ◽  
Compression Tests ◽  
Rotary Drilling ◽  
Static Compression ◽  
Drilling Performance ◽  
Wide Range ◽  
Compression Hysteresis

Abstract One unconventional application that researchers have been investigating for enhancing drilling performance, has been implemented through improving and stabilizing the most effective downhole drilling parameters including (i) increasing downhole dynamic weight on bit (DDWOB), (ii) stabilizing revolution per minutes (rpm), (iii) minimizing destructive downhole vibrations, among many others. As one portion of a three-part-research that consists of a comprehensive data analysis and evaluation of a static compression hysteresis, dynamic compression hysteresis, and corresponding drilling tests, this research investigates through static cyclic loading “Hysteresis” of individual and combined springs and damping the functionality of the passive Vibration Assisted Rotary Drilling (pVARD) tool that could be utilized towards enhancing the drilling performance. Tests are conducted on the two main pVARD tool sections that include (i) Belleville springs, which represent the elasticity portion and (ii) the damping section, which represents the viscous portion. Firstly, tests were conducted through static cyclic loading “Hysteresis” of (i) a mono elastic, (ii) a mono viscus, and (iii) dual elastic-viscus cyclic loading scenarios for the purpose of further examining pVARD functionality. For performing static compression tests, a calibrated geomechanics loading frame was utilized, and various spring stacking of different durometer damping were tested to seek a wide-range data and to provide a multi-angle analysis. Results involved analyzing loading and displacement relationships of individual and combined springs and damping are presented with detailed report of data analysis, discussion, and conclusions.

Dynamic Compression Behavior of Lotus-Type Porous Iron

2010 ◽  
Vol 658 ◽  
pp. 193-196
Author(s):  
Masakazu Tane ◽  
Tae Kawashima ◽  
Keitaro Horikawa ◽  
Hidetoshi Kobayashi ◽  
Hideo Nakajima
Keyword(s):  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
Testing Machine ◽  
Porous Iron ◽  
Compression Tests ◽  
Hopkinson Pressure Bar ◽  
Static Compression ◽  
Plateau Stress ◽  
Stress Region ◽  
Quasi Static Compression

Dynamic and quasi-static compression tests were conducted on lotus-type porous iron with porosity of about 50% using the split Hopkinson pressure bar method and universal testing machine, respectively.　In the dynamic compression parallel to the pore direction, a plateau stress region appears where deformation proceeds at nearly constant stress, while the plateau stress region does not appear in the quasi-static compression. The plateau stress region is probably caused by the buckling deformation of matrix iron which occurs only in the dynamic compression. In contrast, the compression perpendicular to the orientation direction of pores exhibits no plateau-stress regions in the both dynamic and quasi-static compression.

Impact Response and Simulation of Damaged Ulna With Internal Fixation

2012 ◽  
Vol 28 (3) ◽  
pp. 324-334
Author(s):  
Cameron Coates ◽  
Priya Goeser ◽  
Camille Coates-Clark ◽  
Mark Jenkins
Keyword(s):  
Impact Test ◽  
Impact Load ◽  
Impact Damage ◽  
Dynamic Compression ◽  
Dynamic Strain ◽  
Fe Model ◽  
Transverse Impact ◽  
Case Scenario ◽  
Worst Case ◽  
The Impact

The objectives of this work were to explore a methodology that combines static and dynamic finite element (FE) analysis, linear elastic fracture mechanics (LEFM) and experimental methods to investigate a worst-case scenario in which a previously damaged bone plate system is subjected to an impact load. Cadaver ulnas with and without midshaft dynamic compression plates are subjected to a static three-point bend test and loaded such that subcritical crack growth occurs as predicted by a hybrid method that couples LEFM and static FE. The plated and unplated bones are then unloaded and subsequently subjected to a midshaft transverse impact test. A dynamic strain-based FE model is also developed to model the midshaft transverse impact test. The average value of the impact energy required for failure was observed to be 10.53% greater for the plated set. There appears to be a trade-off between impact damage and impact resistance when ulnas are supported by fixation devices. Predictions from the dynamic FE model are shown to corroborate inferences from the experimental approach.

scholarly journals Variable moduli of soil strain

2019 ◽  
Vol 97 ◽  
pp. 04013 ◽  
Author(s):  
Karim Sultanov ◽  
Pavel Loginov ◽  
Sabida Ismoilova ◽  
Zulfiya Salikhova
Keyword(s):  
Modulus Of Elasticity ◽  
Dynamic Compression ◽  
Soft Soil ◽  
Compressive Load ◽  
Loess Soil ◽  
Dynamic Strain ◽  
Static Compression ◽  
Nonlinear Properties ◽  
Strain Components ◽  
Soil Strain

The experimental diagrams between stress and strain components for soft soils are non-linear. Nonlinear diagrams qualitatively differ for soils of undisturbed and disturbed structures. It is believed that the manifestations of nonlinear properties of soil are associated with micro-destruction of soil structure under compression and, therefore, with changes in its mechanical characteristics under strain. It follows that the modulus of elasticity, Poisson’s ratio, viscosity and other mechanical parameters are the variables in the process of soil strain. Based on this, from the experimental results given in scientific literature, the changes in the modulus of elasticity and plasticity of soil are determined depending on the values of compression strain. In the process of static and dynamic compression of soil it is almost impossible to determine the boundaries of elastic and plastic strains in soft soil. So, the modulus under soil compression is called the strain modulus. From published results of experiments on dynamic and static compression of soil the most informative ones have been selected. Processing the selected compression diagrams of soft soil, the secant moduli of strain for loess soil and clay have been determined. It is established that the moduli of strain of clay and loess soil under static and dynamic strain vary depending on the rate of strain, the state of the structure and the level of compressive load.

Dynamic and Quasi-Static Compression Tests for Polylactic Acid Resin Foam

2012 ◽  
Vol 706-709 ◽  
pp. 745-750 ◽  
Author(s):  
Hidetoshi Kobayashi ◽  
Keitaro Horikawa ◽  
Keiko Watanabe ◽  
Kinya Ogawa ◽  
Kensuke Nozaki
Keyword(s):  
Strain Rate ◽  
Polylactic Acid ◽  
High Speed ◽  
Impact Load ◽  
Video Camera ◽  
Compression Tests ◽  
Rate Dependency ◽  
Static Compression ◽  
Acid Resin ◽  
The Impact

In this study, the effect of strain rate on the strength and the absorbed energy of polylactic acid resin foam (PLA-foam), which is generally known as one of carbon-neutral and environmentally-friendly polymers, were examined by a series of compression tests at various strain rates from 0.001 to 750 s-1. For the measurements of the impact load and the displacement of specimen, a special load cell and a high-speed video camera were used, respectively. The flow stress of the PLA-foam strongly depends upon not only strain rate but also density of specimens. Thus, a new technique to eliminate the effect of the difference in the specimen density was proposed and successfully applied. It was also found that the strain-rate dependency of PLA-foam can be expressed by a simple power law.

The effect of loading rate on the elasto-plastic flexure of steel beams

1966 ◽  
Vol 290 (1421) ◽  
pp. 266-285 ◽  
Keyword(s):  
Loading Rate ◽  
Dynamic Compression ◽  
Bending Moment ◽  
Steel Beams ◽  
Beam Specimen ◽  
Strain Rates ◽  
Structural Elements ◽  
Compression Tests ◽  
Pure Bending ◽  
Yield Behaviour

The plastic behaviour of structural elements subjected to dynamic bending is discussed in relation to the strain-rate dependence of the flow stress. Theoretical and experimental work based on the concept of a dynamic fully plastic moment is summarized, with special reference to the yield behaviour of mild steel. A new dynamic loading machine is described which permits the deformation of a beam specimen in pure bending at speeds giving maximum strain rates up to 20 s -1 . The apparatus incorporates transducers which permit the recording of bending moment and deformation rate throughout the test. The paper gives the results of dynamic flexure tests on a 0.10 % carbon steel and also the results of dynamic compression tests on the same material. The relation between the two sets of results is discussed, and it is concluded that the behaviour in bending exhibits features which are not predictable from the compression test data.

scholarly journals Experimental Study on the Mechanical Behavior of EN08 Steel at Different Temperatures and Strain Rates

Metals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 736 ◽  
Author(s):  
Farid Abed ◽  
Akrum Abdul-Latif ◽  
Ayatollah Yehia
Keyword(s):  
Strain Rate ◽  
Mechanical Response ◽  
Dynamic Compression ◽  
Damage Model ◽  
Tensile Tests ◽  
Dynamic Strain ◽  
Uniaxial Tensile ◽  
Strain Rates ◽  
Compression Tests ◽  
Sem Images

The objective of this paper is to investigate the mechanical response of EN08 steel at quasi-static and dynamic strain rates. Uniaxial tensile tests under quasi-static regime (from 0.0015 s−1 to 0.15 s−1) are conducted on EN08 steel at a range of temperatures between 298 K and 923 K. Dynamic compression tests are also performed by using a drop hammer and by considering different masses and heights to study the material response at strain rates up to 800 s−1. Through the stress-strain responses of EN08 steel, a strong dependency of the yield stress as well as the ultimate strength on the strain rate and temperature is recognized. Furthermore, the strain hardening is highly affected by the increase of temperature at all levels of strain rate. The microstructure of the steel is also examined at a fracture by using SEM images to quantify the density of microdefects and define the damage evolution by using an energy-based damage model.

STRAIN CHARACTERISTICS OF SOIL AND METHODS OF THEIR DETERMINATION

2018 ◽  
pp. 39-43
Author(s):  
K.S. Sultanov ◽  
P.V. Loginov ◽  
Z.R. Salikhova
Keyword(s):  
Dynamic Loading ◽  
Dynamic Compression ◽  
Loess Soil ◽  
Seismic Loads ◽  
Static Compression ◽  
Plastic Model ◽  
Laboratory Conditions ◽  
Coefficient Of Viscosity ◽  
Wave Problems

The method to define strain characteristics of soil under dynamic loading is proposed based on the results of experiments on dynamic compression of soils on the device for dynamic loading in laboratory conditions; the method allows solving wave problems with the statement similar to the statement of experiments. Using the proposed method, the modulus of dynamic and static compression, the modulus of unloading, the coefficient of viscosity of loess soil in the range of seismic loads are determined in accordance with elastic-visco-plastic model of soil developed by G.M.Lyakhov.

scholarly journals Influence of artificial aging: mechanical and physicochemical properties of dental composites under static and dynamic compression

2021 ◽  
Author(s):  
D. C. Gornig ◽  
R. Maletz ◽  
P. Ottl ◽  
M. Warkentin
Keyword(s):  
Mechanical Properties ◽  
Water Sorption ◽  
Artificial Aging ◽  
Filler Content ◽  
Dynamic Compression ◽  
The Other ◽  
Chemical Degradation ◽  
Dental Composites ◽  
Compression Tests ◽  
Acid Ph

Abstract Objective The aim of the study was to evaluate the influence of filler content, degradation media and time on the mechanical properties of different dental composites after in vitro aging. Materials and Methods Specimens (1 mm3) of three commercially available composites (GrandioSO®, Arabesk Top®, Arabesk Flow®) with respect to their filler content were stored in artificial aging media: artificial saliva, ethanol (60%), lactic acid (pH 5) and citric acid (pH 5). Parameters (Vickers microhardness, compressive strength, elastic modulus, water sorption and solubility) were determined in their initial state (control group, n = 3 for microhardness, n = 5 for the other parameters) and after 14, 30, 90 and 180 days (n = 3 for microhardness, n = 5 for the other parameters for each composite group, time point and media). Specimens were also characterized with dynamic-mechanical-thermal analysis (compression tests, F =  ± 7 N; f = 0.5 Hz, 1 Hz and 3.3 Hz; t = 0–170 °C). Results Incorporation of fillers with more than 80 w% leads to significantly better mechanical properties under static and dynamic compression tests and a better water sorption behavior, even after chemical degradation. The influence of degradation media and time is of subordinate importance for chemical degradation. Conclusion Although the investigated composites have a similar matrix, they showed different degradation behavior. Since dentine and enamel occur only in small layer thickness, a test specimen geometry with very small dimensions is recommended for direct comparison. Moreover, the use of compression tests to determine the mechanical parameters for the development of structure-compatible and functionally adapted composites makes sense as an additional standard. Clinical relevance Preferential use of highly filled composites for occlusal fillings is recommended.

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