scholarly journals A Review of mathematical models for prediction of Stress-strain and moment –curvature behaviour in concrete

2020 ◽  
Vol 184 ◽  
pp. 01111
Author(s):  
Y Shashank Babu ◽  
V Srinivasa Reddy ◽  
Raju S P V ◽  
M V Seshagiri Rao
Keyword(s):  
Mathematical Models ◽  
Strain Curve ◽  
Empirical Equations ◽  
Stress Strain ◽  
Conventional Concrete ◽  
Strain Behaviour ◽  
Experimental Values ◽  
Good Number ◽  
Made In

In this paper, a mathematical model for predicting the stress –strain and moment curvature relations in concrete is developed. A good number of empirical equations were proposed to represent stress-strain behaviour of conventional concrete. Most of the equations can be used for the ascending portion of the curve only. In 1997 Mansur et al. have adopted Carriera and Chu (1985) model, which was based on the model proposed by Popovics (1973). As such, model proposed by Mansur et al includes both ascending and descending portions of the stress-strain curve for the confined concrete with introduction of two constants for the descending portion of the curve. Several researchers proposed various empirical equations for stress-strain behaviour as briefly reported in the previous chapter. An attempt has been made in this study to develop mathematical models for concrete in unconfined state. These analytical equations can be applied to any concrete with slight modifications. These models are developed to validate the experimental values obtained.

scholarly journals Proposed mathematical model for stress- strain behaviour of geopolymer concrete

2021 ◽  
Vol 309 ◽  
pp. 01053
Author(s):  
Bitla Srivathsav ◽  
N Prem Kumar ◽  
S Shrihari ◽  
C Vivek Kumar
Keyword(s):  
Mathematical Model ◽  
Flexural Behavior ◽  
Polymer Concrete ◽  
Geopolymer Concrete ◽  
Empirical Equations ◽  
Stress Strain ◽  
Strain Behaviour ◽  
Experimental Values ◽  
As Stress ◽  
Stress Block

In the present study, appropriate analytic stress-strain mathematical model is developed that can capture the real (observable) stress-strain behaviour of geo polymer concrete. The geo polymer concrete mixes have shown improved stress values for the same strain levels compared to that of controlled concrete mix in M20 grade. The analytical equations for the stress-strain response of conventional and geopolymer concrete mixes have been proposed in the form of y = Ax / (1+Bx+Cx2), both for ascending and descending portions of the curves with different set of values for constants. The proposed equations have shown good correlation with experimental values. The proposed empirical equations can be used as stress block in analyzing the flexural behavior of sections of controlled and geo polymer concrete. The stress-strain curves obtained in the experiment for M20 & G20 grades of controlled and geo polymer concrete exhibit a similar trend when compared to the empirical equations of modified Saenz model. So Saenz mathematical model is successfully evaluated and validated for geopolymer concrete.

scholarly journals Stress-strain model for grade 275 reinforcing steel with cyclic loading

1978 ◽  
Vol 11 (2) ◽  
pp. 101-109 ◽  
Author(s):  
K. J. Thompson ◽  
R. Park
Keyword(s):  
Axial Loading ◽  
Strain Curve ◽  
Cyclic Stress ◽  
Stress Strain ◽  
Reinforcing Bar ◽  
Strain Behaviour ◽  
Strain Relationship ◽  
Reversed Loading ◽  
Relationship Of ◽  
Strain Model

The stress-strain relationship of Grade 275 steel reinforcing bar under cyclic (reversed) loading is examined using experimental results obtained previously from eleven test specimens to which a variety of axial loading cycles has been applied. A Ramberg-Osgood function is fitted to the experimental stress-strain curves to follow the cyclic stress-strain behaviour after the first load run in the plastic range. The empirical constants in the function are determined by regression analysis and are found to depend mainly on the plastic strain imposed
in the previous loading run. The monotonic stress-strain curve for the steel, with origin of strains suitably adjusted, is assumed to be the envelope curve giving the upper limit of stress. The resulting Ramberg-Osgood expression and envelope is found to give good agreement with the experimentally measured cyclic stress-strain curves.

scholarly journals Axial stress-strain behaviour of pre-damaged square concrete column repaired with FRP jackets

2018 ◽  
Vol 199 ◽  
pp. 09011
Author(s):  
Pengda Li ◽  
Yingwu Zhou ◽  
Ningxu Han ◽  
Feng Xing
Keyword(s):  
Axial Stress ◽  
Strain Curve ◽  
Radius Ratio ◽  
Stress Strain ◽  
Damage Level ◽  
Damage Degree ◽  
Corner Radius ◽  
Strain Behaviour ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer

This paper presents the results of an experimental study on the behaviour of pre-damaged concrete square columns that have been strengthened with carbon fibre-reinforced polymer (CFRP) wrap. Tests were conducted on 46 concrete columns involving variations of corner radius ratio, damage degree, and confinement pressure. The effect of corner radius on the main parameters of stress-strain curve for FRP strengthened pre-damaged specimens, such as compressive strength, strain capacity, initial elastic modulus, was investigated. The test results demonstrated that the efficiency of repairing damaged columns significantly depends on the corner radius ratio, the strength gain after FRP-strengthening decreases as the corner radius ratio reduces. Using those test data, new ultimate strength and ultimate strain model are proposed. The proposed models involved the effect of both corner radius and damage level, showing good agreement with the experimental results.

scholarly journals Effect Of Pre-Tensioned Level on Axial Stress-Strain Behaviour of Confined Concrete: A Review

2018 ◽  
Vol 7 (3.9) ◽  
pp. 18
Author(s):  
Chee Loong Chin ◽  
Chau Khun Ma ◽  
Jia Yang Tan ◽  
Abdullah Zawawi Awang ◽  
Wahid Omar
Keyword(s):  
Reinforced Concrete ◽  
Axial Stress ◽  
Strain Curve ◽  
Confined Concrete ◽  
Reinforced Concrete Buildings ◽  
Short Discussion ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Confining Effect ◽  
Strain Behaviour

External passive confinement has been used as strengthening scheme to rehabilitate existing reinforced concrete buildings. Passive confinement requires a certain lateral dilation of concrete prior to the activation of the confining effect. Applying pre-tensioned force to the confining material can eliminate the needs of such lateral dilation. This paper presents a review on previous studies conducted about pre-tensioned level in confined concrete. A short discussion is done based on the effect of pre-tensioned level to the three regions of stress-strain curve. It was found that pre-tensioned level affects the stress-strain behaviour of confined concrete. Pre-tensioned level that is too high decreases the strain capacity of the confined concrete. This review suggests that there exists an optimum pre-tensioned level for each confining material.  

A model of the continuous elastoplastic transition in metals

1971 ◽  
Vol 6 (3) ◽  
pp. 185-192 ◽  
Author(s):  
W J D Jones ◽  
A K Agarwal
Keyword(s):  
Yield Point ◽  
Strain Curve ◽  
Stress Strain Curve ◽  
Yield Strain ◽  
Stress Strain ◽  
Strain Behaviour ◽  
Aluminium Copper ◽  
Stress Cycling ◽  
Elastoplastic Transition ◽  
Plastic Parts

Part 1: The heterogeneous character of a real metal is represented by a model in which the metal is considered to consist of a large number of elements with a variation of individual stress-strain responses. The variation of Poisson's ratio which occurs as a function of strain is used to measure the progress of yielding through the material and hence to calculate the variation in elemental yield strains. By use of data obtained from the completely elastic and fully plastic parts of the stress-strain curve and the yield strain distribution, the elastoplastic transition behaviour can be calculated. Comparisons are presented between computed and experimental stress-strain curves for aluminium, copper, magnesium, nickel, and titanium alloy to demonstrate the validity of the proposed model. Part 2: Sufficient cyclic stressing can change the subsequent stress-strain curve of a steel which normally has a yield point into one with a continuous elastoplastic transition. A model of the elastoplastic transition in metals, developed by the authors in Part 1 to represent the stress-strain behaviour of metals with a continuous elastoplastic transition, is then proposed for representing the stress-strain behaviour of steels in which the yield point has been removed, by stress cycling. Results are presented to show good agreement between the model and the observed stress-strain behaviour of four steels, one of which had no yield point and the other three had their yield points removed by cyclic stressing.

Effect of Gamma-Irradiation towards Stress-Strain Curve of Single Die QFN Package

2011 ◽  
Vol 694 ◽  
pp. 620-624 ◽  
Author(s):  
Wan Yusmawati Wan Yusoff ◽  
Azman Jalar ◽  
Norinsan Kamil Othman ◽  
Irman Abdul Rahman
Keyword(s):  
Gamma Irradiation ◽  
Strain Curve ◽  
Stress And Strain ◽  
Flexural Stress ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Three Point Bending ◽  
Strain Behaviour ◽  
The Relationship ◽  
Different Doses

The aim of the research was to establish the relationship between stress-strain behaviour of single die Quad Flat No lead (SDQFN) and degradation by gamma irradiation. The SDQFN was exposed to Cobalt-60 with different doses from 0.5 Gy, 1.5 Gy, 5.0 Gy, 10.0 Gy and 50.0 kGy. The three-point bending technique was used to measure the flexural stress and strain of the package behaviour relations. After exposing with gamma radiation, the result showed the decreasing in the strength of the package behaviour of irradiated SDQFN when increasing the dose of gamma irradiation. The highest gamma irradiation dose used in this work produced the highest change in stress-strain behaviour of irradiated SDQFN.

Tensile stress/strain characterization of non-linear materials

1981 ◽  
Vol 16 (2) ◽  
pp. 107-110 ◽  
Author(s):  
J Margetson
Keyword(s):  
Strain Curve ◽  
Uniaxial Stress ◽  
Aerodynamic Heating ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Strain Characterization ◽  
Least Squares Fit ◽  
Experimental Values ◽  
Good Agreement

A uniaxial stress/strain curve is represented empirically by a modified Ramberg-Osgood equation ∊=(σ/E) + (σ/σo)m. Firstly E is extracted then σo and m are determined from two points on the experimental curve. These values are improved iteratively by a least squares fit using all the experimental points on the curve. The procedure is used to generate stress/strain relationships for a variety of materials and there is good agreement with the experimental values. The method is also applied to a simulated aerodynamic heating experiment.

scholarly journals Stress-strain model for prestressing steel with cyclic loading

1978 ◽  
Vol 11 (4) ◽  
pp. 209-218
Author(s):  
K. J. Thompson ◽  
R. Park
Keyword(s):  
Steel Wire ◽  
Strain Curve ◽  
Cyclic Stress ◽  
Experimental Stress ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Prestressing Steel ◽  
Strain Behaviour ◽  
Strain Model ◽  
Previous Loading

Experimental stress-strain curves for repeated tensile loading of
 0.276 in (7 mm) diameter prestressing steel wire in the inelastic range
are presented. A mathematical model employing a modified form of the Ramberg-Osgood function is proposed to describe the cyclic stress-strain behaviour of the prestressing steel. The experimental stress-strain
results are subjected to regression analysis in order to obtain empirical expressions for the constants in the Ramberg-Osgood function. The constants are found to depend on the strain imposed in the previous loading run and the characteristics of the monotonic stress-strain curve. The stress- strain curve for monotonic loading, with suitably adjusted origin of coordinates in the case of significant reversed loads, is used to describe the envelope curve which the steel stresses cannot exceed. The proposed cyclic stress-strain model predicted the experimental curves with good accuracy.

scholarly journals Instrumented indentation for determination of full range stress-strain curves

2014 ◽  
Vol 5 (1) ◽  
pp. 6
Author(s):  
Andreas De Smedt ◽  
Stijn Hertelé ◽  
Matthias Verstraete ◽  
Koen Van Minnebruggen ◽  
Wim De Waele
Keyword(s):  
Full Range ◽  
Accurate Determination ◽  
Strain Curve ◽  
Uniaxial Stress ◽  
Instrumented Indentation ◽  
Stress Strain ◽  
Indentation Force ◽  
Strain Behaviour ◽  
Depth Curve

One common method for the determination of full range stress-strain curves by instrumented indentation is presented and validated for an aluminium alloy. This method relates properties describing the indentation force-depth curve with those describing the uniaxial stress-strain curve as traditionally obtained from a tensile test. The first aim of this paper is to explain the basic concepts of instrumented indentation. Next, the analysis method is presented and validated. This study ends with discussing the uniqueness of the obtained solution. It is concluded that accurate determination of stress-strain behaviour can be realized, but for certain materials two indentations are needed.

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