Is Superposition of Creep Strains Valid for Concretes Subjected to Drying Creep?

2004 ◽  
Vol 101 (5) ◽  
Keyword(s):  
Drying Creep ◽  
Creep Strains

Elasto-plastic and creep behaviour of axially loaded, shouldered tubes

1980 ◽  
Vol 15 (1) ◽  
pp. 21-29 ◽  
Author(s):  
R J Dawson ◽  
H Fessler ◽  
T H Hyde ◽  
J J Webster
Keyword(s):  
Finite Element ◽  
Creep Behaviour ◽  
Equivalent Stress ◽  
Strain Curve ◽  
Equivalent Strain ◽  
Uniaxial Tensile ◽  
Plastic Strain Increment ◽  
Axially Loaded ◽  
Initial Strains ◽  
Creep Strains

This paper compares the finite element predictions of elasto-plastic and creep behaviour with experimental data for axially loaded, shouldered tube models. Four shouldered tube models were made of a lead alloy and tested at 61°C, using strain gauges to measure the elasto-plastic and creep strains in the plain tube and fillet regions of the models. Instantaneous stress-strain and creep data were obtained from strain-gauged, uniaxial tensile specimens. The finite element solutions are based on the incremental Prandtl-Reuss equations. The elasto-plastic iterative solutions use a ‘negative gradient’ from the calculated point to the equivalent stress-equivalent strain curve to get the next estimate of the plastic strain increment. A time incremental method is used to obtain the creep solutions. Tests with the mean tube stress below, at and above the yield stress showed very good agreement between prediction and measurement of initial strains in the fillets. Differences between predictions and measurements of creep strains are attributable to cast-to-cast variations.

scholarly journals Temperature influence on creep of reinforced concrete

2020 ◽  
Vol 13 (6) ◽  
Author(s):  
Edmilson Lira Madureira ◽  
Brenda Vieira Costa Fontes
Keyword(s):  
Reinforced Concrete ◽  
Moisture Content ◽  
Alternative Model ◽  
Sustained Load ◽  
Structural Members ◽  
Temperature Influence ◽  
Stress Increase ◽  
Concrete Members ◽  
Over Time ◽  
Creep Strains

abstract: The creep of concrete promotes strains over time in structural members kept under sustained load. It causes the stress decrease on the concrete and the steel stress increase in reinforced concrete members. The moisture content and temperature influence significantly such phenomenon. The creep strains model of the NBR 6118/2014 [1] is, applicable, solely, to those cases of constant stress magnitudes. Reinforced concrete members exhibit variations on the stress magnitudes and, in this way, requires the use of an alternative model for the prediction of the creep strains as the so known the State Model. This report refers itself to temperature influence analysis upon creep strains of reinforced concrete structural members. The results have revealed that temperature speeds up the creep effects and, in this way, the steel yielding caused by the stress increase on the reinforcement bars occurs at earlier ages.

Residual Life Assessment for Boiler Pressure Components Based on Measurements of Creep Strains

1988 ◽  
Vol 110 (3) ◽  
pp. 308-313 ◽  
Author(s):  
F. Mlynarski ◽  
J. Taler
Keyword(s):  
Residual Life ◽  
Life Assessment ◽  
Strain Measurements ◽  
Years Of Service ◽  
Residual Life Assessment ◽  
Outside Diameter ◽  
Creep Strains

This paper discusses different methods for calculating the residual life for boiler pressure components operating under creep conditions, based on tube outside diameter strain measurements. These measurements were made for over 20 yr. The methods have been applied to the residual life calculation for pipelines of 20 or more years of service. Then the results have been compared.

The effect of rate of drying on the drying creep of hardened cement paste

1984 ◽  
Vol 14 (3) ◽  
pp. 329-338 ◽  
Author(s):  
R.L. Day ◽  
P. Cuffaro ◽  
J.M. Illston
Keyword(s):  
Cement Paste ◽  
Hardened Cement ◽  
Hardened Cement Paste ◽  
Drying Creep

Predicting Thermal Fatigue Lifetimes for SMT Solder Joints

1992 ◽  
Vol 114 (4) ◽  
pp. 472-476 ◽  
Author(s):  
J. Sauber ◽  
J. Seyyedi
Keyword(s):  
Finite Element ◽  
Solder Joint ◽  
Thermal Cycling ◽  
Thermal Fatigue ◽  
Solder Joints ◽  
Finite Element Models ◽  
Creep Tests ◽  
Creep Equation ◽  
Joint Behavior ◽  
Creep Strains

A power-law type creep equation has been added to finite element models to calculate solder joint response to time, temperature, and stress level. The ability of the models to predict solder joint behavior was verified by running a series of creep tests. The models were then solved to determine the solder joint creep strains which occur during thermal cycling. These creep strains were used to predict the degradation of pull strength resulting from thermal cycling. More than 8,600 solder joints were thermally cycled and then individually pull tested to verify the accuracy of the method.

Creep Properties of Steels Utilized in High-Pressure and High-Temperature Superheater and Steam Pipe Practice. Part I: Carbon Steels

1944 ◽  
Vol 151 (1) ◽  
pp. 54-62 ◽  
Author(s):  
H. J. Tapsell
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Carbon Steels ◽  
Creep Properties ◽  
Molybdenum Steel ◽  
Steam Pipe ◽  
Steam Pipes ◽  
Sufficient Precision ◽  
Creep Strains

This report deals with the creep properties of carbon steels used in superheater headers, superheater tubes, and steam pipes for service at temperatures up to about 480 deg. C. The object of the investigation was to obtain data for the estimation of the stress-temperature relationships for specific creep strains of 0·1–0·5 per cent to occur in 100,000 hours, and these have been obtained with sufficient precision to warrant their acceptance for practical purposes. Similar components in molybdenum steel are under investigation.

Analytical Solution for the Creep Problem of a Rotating Functionally Graded Magneto–Electro–Elastic Hollow Cylinder in Thermal Environment

2019 ◽  
Vol 11 (06) ◽  
pp. 1950053 ◽  
Author(s):  
M. Saadatfar
Keyword(s):  
Differential Equation ◽  
Hollow Cylinder ◽  
Thermal Loading ◽  
Thermal Environment ◽  
Functionally Graded ◽  
Time Dependent ◽  
Creep Stress ◽  
Creep Analysis ◽  
Magnetic Potentials ◽  
Creep Strains

In this paper, an analytical method is presented for the problem of the time-dependent response of a functionally graded magneto–electro–elastic (FGMEE) rotating hollow cylinder in thermal environment. The material properties of FGMEE are supposed to be power-law functions of radius. Applying the equations of equilibrium and electrostatic and magnetostatic equations, a differential equation which includes creep strains is achieved. At first, an exact solution for the primitive stresses, electric and magnetic potentials are achieved by eliminating creep strains in the mentioned differential equation. Then, Prandtl–Reuss equations, as well as Norton’s law, are employed for the FGMEE. Now, creep stress rates can be achieved by considering only creep strains in the mentioned differential equation. As a final step, time-dependent creep stress, electric potential and magnetic potential redistributions at any time can be achieved using an iterative method. Numerical examples are presented to disclose the influence of creep evolution, thermal loading, angular velocity and grading index on the primitive and creep response of the FGMEE hollow cylinder. Results show that the enhancement in tensile hoop stress during the creep evolution must be considered in designing. So, the creep analysis is vital to have more reliable and accurate aerospace smart structures.

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