scholarly journals Experimental Investigation of the Tension and Compression Creep Behavior of Alumina-Spinel Refractories at High Temperatures

Ceramics ◽  
2020 ◽  
Vol 3 (3) ◽  
pp. 372-383
Author(s):  
Lucas Teixeira ◽  
Soheil Samadi ◽  
Jean Gillibert ◽  
Shengli Jin ◽  
Thomas Sayet ◽  
...  
Keyword(s):  
Creep Behavior ◽  
Working Life ◽  
Refractory Materials ◽  
Secondary Creep ◽  
Inverse Identification ◽  
Creep Tests ◽  
Identification Procedure ◽  
Compression Creep ◽  
Experimental Creep ◽  
Tension And Compression

Refractory materials are subjected to thermomechanical loads during their working life, and consequent creep strain and stress relaxation are often observed. In this work, the asymmetric high temperature primary and secondary creep behavior of a material used in the working lining of steel ladles is characterized, using uniaxial tension and compression creep tests and an inverse identification procedure to calculate the parameters of a Norton-Bailey based law. The experimental creep curves are presented, as well as the curves resulting from the identified parameters, and a statistical analysis is made to evaluate the confidence of the results.

scholarly journals Influence of Normal Stress on Creep in Tension and Compression of Polyethylene and Rigid Polyvinyl Chloride Copolymer

1962 ◽  
Vol 84 (2) ◽  
pp. 237-246 ◽  
Author(s):  
D. G. O’Connor ◽  
W. N. Findley
Keyword(s):  
Normal Stress ◽  
Polyvinyl Chloride ◽  
Material Structure ◽  
Reasonable Accuracy ◽  
Creep Tests ◽  
Compression Creep ◽  
Cent Relative Humidity ◽  
Tension And Compression ◽  
New Apparatus ◽  
Shear Planes

New apparatus suitable for compression creep tests of slender specimens is described. The apparatus is designed to prevent buckling and to introduce a minimum of friction. Results are reported for tension and compression creep of polyethylene and annealed, unplasticized polyvinyl chloride copolymer at 75 deg F and 50 per cent relative humidity. The stress σ, strain ε, time t data from these tests were found to be describable with reasonable accuracy by the equation ε=ε0′sinhσ/σε+m′tnsinhσ/σm where ε0′, m′, n, σε, and σm are material constants. The results for polyethylene show that the creep in tension and compression were virtually the same. However, the creep in tension was similar but larger than in compression for polyvinyl chloride. These observations are interpreted in terms of the material structure and the influence of the normal stress on active shear planes.

scholarly journals Prediction of creep behavior of laminated woven fabric with adhesive interlining under low stress in the bias direction

2016 ◽  
Vol 87 (3) ◽  
pp. 285-295 ◽  
Author(s):  
Masayuki Takatera ◽  
Ken Ishizawa ◽  
KyoungOk Kim
Keyword(s):  
Creep Strain ◽  
Creep Behavior ◽  
Viscoelastic Model ◽  
Element Model ◽  
Woven Fabric ◽  
Creep Model ◽  
Creep Tests ◽  
Viscoelastic Models ◽  
Experimental Creep ◽  
The Face

The effect of adhesive interlining on the creep behavior of a woven fabric in the bias direction was investigated. Three-element viscoelastic models were used to approximate the creep behavior of a face fabric and adhesive interlining. The creep model of a laminated fabric comprised a six-element model in which two three-element models are connected in parallel with the three-element model. Creep tests were carried out using face fabrics, adhesive interlinings, and their laminated fabrics without and with bonding adhesive interlining by hanging samples in the 45° bias direction under their own weight for 7 days. Creep strains of face fabrics bonded with adhesive interlining were found to be weaker than those of the face fabrics. The creep behavior for the face and interlining fabrics could be approximated using the three-element viscoelastic model with appropriate parameters. The experimental creep behavior of a laminated fabric without bonding was similar to the theoretical behavior. However, the experimental creep of laminated fabrics with bonding interlining was less than the calculated creep, owing to the increase in stiffness due to the adhesive. By revising the six-element model with the strains just after hanging and for 2 days, it was possible to predict the creep strain over 7 days.

Creep Behavior for Alloy 617 in Air at 950°C

2010 ◽  
Vol 654-656 ◽  
pp. 508-511 ◽  
Author(s):  
Woo Gon Kim ◽  
Song Nan Yin ◽  
Gyeong Geon Lee ◽  
Yong Wan Kim
Keyword(s):  
Creep Behavior ◽  
Primary Creep ◽  
Secondary Creep ◽  
Creep Tests ◽  
Alloy 617 ◽  
Very High Temperature Reactor ◽  
Creep Curves ◽  
High Temperature Reactor ◽  
Very High ◽  
Cr2o3 Layer

Creep behavior for Alloy 617, which is considered as one of the major structural materials of a very high temperature reactor, was investigated in air at 950oC. Creep experimental data was obtained by a series of creep tests with different stress levels at 950oC. Alloy 617 revealed little primary creep strains and unclear secondary creep stages. A tertiary creep stage was initiated from a low strain level and was dominant in full creep curves. The creep constants of A, n, m, and C in Norton’s power law and Monkman-Grant relationships were determined. In microstructure observations of crept specimens, it was found that a Cr2O3 oxidation layer was formed on the surface, and just beneath the Cr2O3 layer, an internal Al-oxide sub layer was formed with rod shapes. Also, below the internal sub layer, a thick carbide-depleted zone was developed due to reaction of the chromia and carbide precipitates. The thickness of the outer Cr-oxide layer increased with increasing creep rupture times. The increasing tendency showed a smooth slope like a parabolic curve.

Creep Behavior of the Inconel 718 Superalloy

2012 ◽  
Vol 326-328 ◽  
pp. 509-514 ◽  
Author(s):  
Tarcila Sugahara ◽  
Karina Martinolli ◽  
Danieli A.P. Reis ◽  
Carlos de Moura Neto ◽  
Antônio Augusto Couto ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Creep Behavior ◽  
Inconel 718 ◽  
Base Alloy ◽  
High Surface ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Secondary Creep ◽  
Creep Tests ◽  
Surface Stability

A superalloy is an alloy developed for elevated temperature service, where relatively severe mechanical stressing is encountered, and where high surface stability is frequently required. High temperature deformation of Ni-base superalloys is very important since the blades and discs of aero engine turbine, because need to work at elevated temperature for an expected long period. The nickel-base alloy Inconel 718 has being investigated because it is one of the most widely used superalloys. The objective of this work was to evaluate the creep behavior of the Inconel 718 focusing on the determination of the experimental parameters related to the primary and secondary creep states. Constant load creep tests were conducted with at 650, 675 and 700°C and the range of stress was from 625 to 814 MPa to according to ASTM E139 standard. The relation between primary creep time and steady-state creep rate, obeyed the equation for both atmospherics conditions at 650, 675 and 700°C. The microstructural characterization employing the technique of scanning electron microscopy has been a valuable tool for understanding the mechanisms of creep.

scholarly journals A simple and updated pneumatic method for uniaxial ice compression in the laboratory: experimental settings and creep test results on glacier ice

2011 ◽  
Vol 57 (202) ◽  
pp. 337-344 ◽  
Author(s):  
D. Samyn ◽  
M. Dierckx ◽  
J.-P. Remy ◽  
T. Goossens ◽  
J.-L. Tison
Keyword(s):  
Experimental Studies ◽  
Published Data ◽  
Secondary Creep ◽  
Atmospheric Conditions ◽  
Creep Tests ◽  
Compression Creep ◽  
External Cooling ◽  
Cold Room ◽  
Glacier Ice ◽  
Pneumatic Method

AbstractCreep tests provide invaluable data to better understand the physical properties of ice under various conditions. We describe here a simple, updated pneumatic apparatus for experimental studies of ice rheological properties. The apparatus is designed to perform two simultaneous compression creep tests either in a cold room or in atmospheric conditions when coupled to an external cooling circulator. We present results from calibration tests of the apparatus and provide new data from creep tests performed on temperate glacier ice samples. These calibration and creep results show that the apparatus is able to provide fast and reliable mechanical ice characterization. The secondary creep rates measured in this study range between 1.59 × 10−8 s−1 (at 0.21 MPa) and 4.38 × 10−7 s−1 (at 0.71 MPa) at −10°C for quasi-isotropic ice, which is consistent with former standard published data. The corresponding mean parameter, A, is 5.20 × 10−16 s−1 kPa−3, which also compares well with the range of reported other studies.

scholarly journals High Temperature Behavior of Al-7Si-0.4Mg Alloy with Er and Zr Additions

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 879
Author(s):  
Elisabetta Gariboldi ◽  
Chiara Confalonieri ◽  
Marco Colombo
Keyword(s):  
High Temperature ◽  
Eutectic Silicon ◽  
A356 Alloy ◽  
Minor Element ◽  
High Temperature Strength ◽  
Creep Tests ◽  
Casting Alloys ◽  
Compression Creep ◽  
Tension And Compression

In recent years, many efforts have been devoted to the development of innovative Al-based casting alloys with improved high temperature strength. Research is often oriented to the investigation of the effects of minor element additions to widely diffused casting alloys. The present study focuses on Al-7Si-0.4Mg (A356) alloy with small additions of Er and Zr. Following previous scientific works on the optimization of heat treatment and on tensile strength, creep tests were carried out at 300 °C under applied stress of 30 MPa, a reference condition for creep characterization of innovative high-temperature Al alloys. The alloys containing both Er and Zr displayed a lower minimum creep strain rate and a longer time to rupture. Fractographic and microstructural analyses on crept and aged specimens were performed to understand the role played by eutectic silicon, by the coarse intermetallics and by α-Al matrix ductility. The creep behavior in tension of the three alloys has been discussed by comparing them to tension and compression creep curves available in the literature for Al-7Si-0.4Mg improved by minor elemental additions.

scholarly journals Creep Strain Analysis and an Improved Creep Model of Granite Based on the Ratio of Deviatoric Stress-Peak Strength under Different Confining Pressures

2021 ◽  
Author(s):  
Li Qian ◽  
Jianhai Zhang ◽  
Xianliang Wang ◽  
Yonghong Li ◽  
Ru Zhang ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Creep Behavior ◽  
Viscosity Coefficient ◽  
Deviatoric Stress ◽  
Peak Strength ◽  
Creep Model ◽  
Secondary Creep ◽  
Creep Tests ◽  
Underground Powerhouse ◽  
Confining Pressures

Abstract Creep refers to the deformation of rock with time under long-term applied stress, which occur in most underground engineering. The creep behavior of granite in Shuang jiangkou underground powerhouse in Western Sichuan Province, China, was studied by creep tests. Based on test results, a new parameter DPR, the ratio of deviatoric stress to peak strength, is proposed. DPR is found to be a key parameter to describe creep parameters such as instantaneous elastic modulus, creep elastic modulus, and viscosity coefficient of rock under different confining pressures. Creep tests show that instantaneous elastic modulus increases with the increase of DPR. Creep elastic modulus increases when DPR changes from 0.54 to 0.7004, but decreases when DPR is from 0.7004 to 0.88, indicating fractures in rock closes firstly and then new fractures are generated. The viscosity coefficient of the rock increases first and then decreases with the increase of DPR, and when DPR = 0.7171, viscosity coefficient is maximum, indicating the time for rock to reach stability is the longest in creep tests. By introducing DPR and confining pressure into creep model, which interconnect creep parameters in a unified expression, an improved generalized Kelvin creep model is proposed which can accurately describe the primary and the secondary creep behavior of granite under given deviatoric stresses and confining pressures.

Creep Behavior of a TWARON®/Natural Rubber Composite

2010 ◽  
Author(s):  
N. V. David ◽  
X.-L. Gao ◽  
J. Q. Zheng
Keyword(s):  
Natural Rubber ◽  
Creep Behavior ◽  
Rheological Model ◽  
Axial Strain ◽  
Time Spectrum ◽  
Secondary Creep ◽  
Creep Tests ◽  
Creep Response ◽  
Rubber Composite ◽  
Different Levels

The creep behavior of a Twaron CT709® fabric/natural rubber composite under a uniaxial constant stress is studied using three viscoelasticity models with different levels of complexity and a newly developed para-rheological model. The three models employed are a one-term generalized Maxwell (GMn = 1) model (consisting of one Maxwell element and an additional spring in parallel), a two-term generalized Maxwell (GMn = 2) model (including two parallel Maxwell elements and an additional spring in parallel), and a four-parameter Burgers model. The values of the parameters involved in each model are extracted from the experimental data obtained in this study. The creep tests reveal that the axial strain starts to increase exponentially during the primary stage and then continues to equilibrate linearly with time. The results show that the initial creep response of the composite is predicted fairly well by the GMn = 2 model, while the secondary creep is more accurately described by the GMn = 1 model. An implicit solution, together with a characteristic retardation time spectrum, obtained using the para-rheological model is found to provide more accurate predictions of the composite creep response than the three viscoelasticity models at both the primary and secondary stages.

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