Predicting macroscopic plastic flow of high-performance, dual-phase steel through spherical nanoindentation on each microphase

2009 ◽  
Vol 24 (3) ◽  
pp. 816-822 ◽  
Author(s):  
Byoung-Wook Choi ◽  
Dong-Han Seo ◽  
Jang-Yong Yoo ◽  
Jae-il Jang
Keyword(s):  
Plastic Flow ◽  
High Performance ◽  
Dual Phase Steel ◽  
Pipeline Steel ◽  
Strain Curve ◽  
Indentation Hardness ◽  
Additional Consideration ◽  
Constraint Factor ◽  
Stress Strain ◽  
Soft Ferrite

An attempt was made to predict the macroscopic plastic flow of a high-performance pipeline steel, consisting of dual constituent phases (soft ferrite and hard bainite), by performing nanoindentation experiments on each microphase with two spherical indenters that have different radii (550 nm and 3.3 μm). The procedure is based on the well known concepts of indentation stress-strain and constraint factor, which make it possible to relate indentation hardness to the plastic flow of the phases. Additional consideration of the indentation size effect for sphere and application of a simple “rule-of-mixture” led us to a reasonably successful estimation of the macroscopic plastic flow of the steel from the microphases properties, which was verified by comparing the predicted stress-strain curve with that directly measured from the conventional tensile test of a bulky sample.

A Novel Method to Predict the Mechanical Properties of DP600

2019 ◽  
Vol 795 ◽  
pp. 22-28
Author(s):  
Yun Qiang Peng ◽  
Li Xun Cai ◽  
Di Yao ◽  
Hui Chen ◽  
Guang Zhao Han
Keyword(s):  
Dual Phase Steel ◽  
Fracture Criterion ◽  
Strain Curve ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Small Punch ◽  
Critical Fracture ◽  
Stress Strain Relation ◽  
Novel Method ◽  
Related Stress

A small punch testing (SPT)-related stress-strain relation (SPT-SR) model is used to obtain the stress-strain curve of DP600 according to Chen-Cai equivalent energy method. And then the SPT and notched small punch testing (NSPT) specimens were simulated in order to determine the critical fracture criterion of DP600 on the basis of the stress-strain curve obtained by SPT-SR model. Lastly, the J resistance curve of small C-shaped inside edge-notched tension (CIET) specimen for DP600 dual-phase steel was successfully predicted based on the aforementioned fracture criterion.

Flexural Behavior of Prestressed UHPC Beams

2011 ◽  
Vol 243-249 ◽  
pp. 1145-1155
Author(s):  
Jian Yang ◽  
Zhi Fang ◽  
Gong Lian Dai
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Strain Curve ◽  
Flexural Behavior ◽  
Experimental Program ◽  
Ultra High Performance Concrete ◽  
Stress Strain ◽  
Flexural Response ◽  
Strain Relationship ◽  
Relationship Of

Ultra High Performance Concrete (UHPC), which has very special properties that are remarkably different to the properties of normal and high performance concrete, is being increasingly used for the construction of structure. In this paper, an experimental program was formulated to investigate the characteristics of complete stress-strain curve of UHPC in uniaxial compression and flexural behaviors of prestressed UHPC beams. The particular focus was the influence of the partial prestress ratio and jacking stress on the flexural response of UHPC beams. The results show that UHPC is of good deformability, and a general form of the serpentine curve is proposed to represent the complete stress-strain relationship of UHPC in compression. The tests of beams demonstrated that the UHPC beams have an excellent behavior in load carrying capacity, crack distribution and deformability, their ultimate deflection can reach 1/34～1/70 of the span. Based on this investigation, theoretical correlations for the prediction structure response of UHPC beam are proposed.

Predicting Flow Curves of Q&P Steel Using Sharp Pyramidal Nanoindentation on Constituent Phases: Isostrain Method

2021 ◽  
Vol 1160 ◽  
pp. 83-91
Author(s):  
M. Karam-Abian ◽  
A. Zarei-Hanzaki ◽  
A.H. Shafieizad ◽  
A. Zinsaz-Borujerdi ◽  
S. Ghodrat
Keyword(s):  
Plastic Flow ◽  
Flow Behavior ◽  
Strain Curve ◽  
Bulk Sample ◽  
Constraint Factor ◽  
Flow Curves ◽  
Factor Ii ◽  
Successful Prediction ◽  
Tensile Curve ◽  
Using Data

In this research, a method is presented for predicting macroscopic plastic flow behavior of a quench and partitioning (Q&P) steel using data of nanoindentation experiments.The method is based on Tabor’s model in which nanohardness values obtained with indenters of different angles to be connected to the flow behavior of the indented material. The process consists of two steps: (i) the macroscopic flow relation of each microphases assessed based on the characteristic strain and constraint factor, (ii) the total flow curve of the steel extracted through an isostrain manner. A rationally successful prediction of the macroscopic plastic flow of the Q&P steel is obtained from the constituent phases properties due to consideration of the indentation size effect and application of a rule of-mixture. Eventually, the accuracy of the estimation is verified by comparing the predicted stress-strain curve to the tensile curve obtained from a standard bulk sample.

A Mathematical Treatment of a Theory of Rubber Structure

1935 ◽  
Vol 8 (1) ◽  
pp. 23-38
Author(s):  
T. R. Griffith
Keyword(s):  
Elastic Modulus ◽  
Plastic Flow ◽  
Strain Curve ◽  
The Other ◽  
Stress Axis ◽  
Mathematical Treatment ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Joule Effect ◽  
Vulcanized Rubber

Abstract A brief consideration of the work that has been done on the structure of rubber convinces, one that the elasticity is wholly or at least mainly explained by a consideration of the kinetics involved. The fact that when a strip of stretched rubber, one end of which is free, contracts when it is warmed, contrary to the behavior of most bodies, and that it becomes warmed on stretching, commonly known as the Gough-Joule effect, pp. 453–461, would lead one to suspect .that there is a connection between the kinetic energy of the rubber molecule and its elasticity. Lundal, Bouasse, Hyde, Somerville and Cope, Partenheimer and Whitby and Katz have reported observations, principally stress-strain curves, which show that vulcanized rubber has a lower modulus of elasticity at higher temperatures, i. e., it becomes easier to stretch as the temperature is raised. On the other hand, Schmulewitsch, Stevens, and Williams found that the elastic modulus increases with the temperature. Williams shows that the softening of vulcanized rubber with rise of temperature is due to an increase of plasticity. In order to get rid of plastic flow, he first stretches the specimen several times to within about 50 per cent of its breaking elongation, and then obtains an autographic stress-strain curve of the rubber stretched very quickly. He finds that in this case the rubber actually becomes stiffer with rise of temperature, increasing temperatures causing the stress-strain curves to lean progressively more and more toward the stress axis. He concludes that rise of temperature has two effects, one a softening due to increase of plasticity, rendering plastic flow more easy, the other an actual stiffening of the rubber due to rise of temperature. It is not easy to explain the latter effect on any theory which does not take kinetics into account.

Strain-Rate Effects on Constitutive Behavior of Sn3.8-Ag0.7-Cu Lead-Free Solder

2009 ◽  
Author(s):  
Kok Ee Tan ◽  
John H. L. Pang
Keyword(s):  
Strain Rate ◽  
Yield Stress ◽  
Strain Curve ◽  
Tensile Tests ◽  
Lead Free ◽  
Indentation Hardness ◽  
Strain Rates ◽  
Test Results ◽  
Stress Strain Curve ◽  
Stress Strain

In this paper, the strain-rate dependent mechanical properties and stress-strain curve behavior of Sn3.8Ag0.7Cu (SAC387) solder is presented for a range of strain-rates at room temperature. The apparent elastic modulus, yield stress properties and stress-strain curve equation of the solder material is needed to facilitate finite element modeling work. Tensile tests on dog-bone shaped bulk solder specimens were conducted using a non-contact video extensometer system. Constant strain-rate uni-axial tensile tests were conducted over the strain-rates of 0.001, 0.01, 0.1 and 1 (s−1) at 25°C. The effects of strain-rate on the stress-strain behavior for lead-free Sn3.8Ag0.7Cu solder are presented. The tensile yield stress results were compared to equivalent yield stress values derived from nano-indentation hardness test results. Constitutive models based on the Ramberg-Osgood model and the Cowper-Symond model were fitted for the tensile test results to describe the elastic-plastic behavior of solder deformation behavior.

Experimental Study on the Uniaxial Compression Curves of Green High-Performance Fiber-Reinforced Cementitious Composites (GHPFRCC)

2014 ◽  
Vol 893 ◽  
pp. 201-204
Author(s):  
Xiu Ling Li ◽  
Juan Wang
Keyword(s):  
Uniaxial Compression ◽  
High Performance ◽  
Strain Curve ◽  
Cementitious Composites ◽  
Peak Strain ◽  
Fiber Reinforced ◽  
Compression Tests ◽  
Stress Strain ◽  
High Performance Fiber ◽  
Fiber Reinforced Cementitious Composites

Green high performance fiber reinforced cementitious composites (GHPFRCC) is the optimized mix proportion of engineered cementitious composites (ECC) with high volume of fly ash and polyvinyl alcohol (PVA) fiber. To study the compressive performance, the prism stress-strain relationship of GHPFRCC is the focus in this study. There are sixteen groups of GHPFRCC specimens with the size 40mm×40mm×160mm. The compressive stress-strain curves were obtained based on the uniaxial compression tests. Experimental results show that the uniaxial compression stress-strain curve belongs to the skewed unimodal curve. The peak strain can steadily reach more than 0.005, and it has put up a great plastic deformation capacity and post-peak ductility. It has still reserved some residual strength even when the strain is up to a bigger value. The research achievements can promote the application of GHPFRCC in the practical engineering.

The Stress-Strain Relationship in Ebonite

1934 ◽  
Vol 7 (1) ◽  
pp. 197-211
Author(s):  
B. L. Davies
Keyword(s):  
Tensile Strength ◽  
Plastic Flow ◽  
Testing Machine ◽  
Strain Curve ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Tensile Testing Machine ◽  
Hooke’S Law ◽  
Hooke's Law ◽  
Soft Rubber

Abstract 1. A simple “extensometer” has been devised for the more accurate measurement of small elongations in hard rubber samples, thus enabling stress-strain curves to be obtained on a standard tensile testing machine. 2. The form of the curve has been described more fully than heretofore. It shows that hard rubber does not deform exactly in accordance with Hooke's Law, but exhibits plastic flow. 3. Deviations from Hooke's Law shown by the experimental curves depend upon the speed of stretching. Increased speed of elongation has been found to give higher readings of tensile strength. 4. Prolonged mastication of the rubber gives a weaker product, similar effects being obtainable by the use of a neutral softener. 5. The effects of increasing time of vulcanization have been described. The range of curves showing transition from over-cured soft rubber to ebonite indicates that the hard rubber curve is possibly related to the initial portion of the soft rubber curve. The plasticity of the overvulcanized rubber, as indicated by the deviation from Hooke's Law, increased with time of vulcanization until the “semi-ebonite” stage was reached. 6. The leather-like “semi-ebonites” differed from soft and hard rubber inasmuch as they were extremely sensitive to small changes in time of vulcanization, and inasmuch as their plasticity was such that the velocity of plastic flow was comparable with the rate of pulling (1 in. per minute), at a particular point in the test they experienced a large elongation at constant load, i. e., the velocity of flow was equal to the speed of pulling. Their plasticity decreased with further vulcanization. 7. The longest cures in the above-mentioned group gave products which were rigid at room temperature. Since these must be more resistant to shock than vulcanizates in a higher state of cure, it seems that the best technical cure of ebonite for mechanical purposes is that which gives maximum tensile strength combined with the property of undergoing considerable plastic flow (of the order of 5 per cent) at the constant maximum load, and at an arbitrarily fixed rate of stretching, the temperature being commensurate with the thermal conditions of service. Such a cure is clearly indicated by the stress-strain curve. 8. Accelerated ebonite mixings are more sensitive to time of cure than rubber-sulfur stocks without accelerators. An accelerator may produce very little effect on the tensile strength and breaking elongation, but may yield a stock which “scorches” readily. This prevulcanization was detrimental to the mechanical properties of the vulcanizate, even though it was so slight that its presence was not detected during normal processing. 9. Mineral rubber in ebonite stocks has been shown to accelerate the cure as indicated by the stress-strain curve. 10. Stocks containing high loadings of gas black gave vulcanizates which were weak and brittle. The effect of the black on the stiffness was similar to that produced by further cure. 11. The stress-strain curve provides a reliable means whereby stocks containing different accelerators and other compounding ingredients may be compared at equivalent states of vulcanization.

Strain-Hardening Properties of High Grade Line Pipes

2018 ◽  
Vol 913 ◽  
pp. 331-339 ◽  
Author(s):  
Ling Kang Ji ◽  
Hui Feng ◽  
Ji Ming Zhang ◽  
Hong Yuan Chen
Keyword(s):  
Strain Hardening ◽  
Pipeline Steel ◽  
Strain Curve ◽  
Study Phase ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Line Pipe ◽  
Hardening Behavior ◽  
Transverse Tensile ◽  
Strain Hardening Behavior

The strain-hardening performance and characteristics of pipeline steel material have an important influence on the deformation behavior and arrest behavior of the line pipe. In this paper X70, selected, and the longitudinal and transverse tensile stress-strain curve and strain-hardening characteristics were analyzed. The results showed that the strain hardening exponent of the double-phased line pipes derived from the transvers stress-strain curve maintains relatively low level at early stage and increased gradually with variation of strain, which was different from the strain hardening behavior for the rest line pipes in this study. Phase ratio, grain size and dislocation density, precipitation, texture, etc. have an effect to the strain hardening behavior of pipeline steel.

The Stress-Strain Behavior of Densified Mix Design of Concrete

2002 ◽  
Vol 18 (4) ◽  
pp. 185-192
Author(s):  
Ping-Kun Chang
Keyword(s):  
High Performance ◽  
Strain Softening ◽  
High Performance Concrete ◽  
Strain Curve ◽  
Type I ◽  
Peak Strain ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Strain Behavior ◽  
Slump Flow

ABSTRACTThis paper investigates the compressive strength and workability of High-Performance Concrete (HPC) which yields a slump at 250 ± 20mm and a slump flow at 650 ± 50mm. From the complete stress-strain curve, it shows the peak strain will be higher while the strength increases. Two kinds of the post failure models can be distinguished. The first type (Type I) is called strain softening and the second type (Type II) is called strain snapping back. Also, it is found that the modulus of elasticityEcdecreases as the volume of cementitious pasteVpincreases. On the other hand, Poisson's ratio ν increases asVpincreases.

scholarly journals Mechanical Properties of High-Performance Lightweight Aggregate Concrete with Inorganic Polymers Cement Based on Multiple Minerals under Uniaxial Loading

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Xiao Ma ◽  
Qiuhua Rao
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Strain Curve ◽  
Lightweight Aggregate ◽  
Lightweight Aggregate Concrete ◽  
Inorganic Polymers ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Aggregate Concrete ◽  
New Material

High-performance lightweight aggregate concrete with inorganic polymers cement based on multiple minerals is a very promising new material. The research of mechanical properties of the new material is of great theoretical and practical significance. In this research, the failure behavior, cubic and prism compressive strength, elastic modulus, peak strain of the new material, and the nature of the stress-strain curve are studied. An analytical model is quoted to represent the ascending and descending parts of the stress-strain curve.

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