scholarly journals Extended Residual-State Creep Test and Its Application for Landslide Stability Assessment

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1968
Author(s):  
Deepak R. Bhat ◽  
Janusz V. Kozubal ◽  
Matylda Tankiewicz
Keyword(s):  
Shear Stress ◽  
Creep Test ◽  
Creep Behavior ◽  
Residual Strength ◽  
Failure Time ◽  
Limit State ◽  
Secondary Creep ◽  
Strength Condition ◽  
Saturation State ◽  
Rock Creep

This paper contains the results of a newly developed residual-state creep test performed to determine the behavior of a selected geomaterial in the context of reactivated landslides. Soil and rock creep is a time-dependent phenomenon in which a deformation occurs under constant stress. Based on the examination results, it was found that the tested clayey material (from Kobe, Japan) shows tertiary creep behavior only under shear stress higher than the residual strength condition and primary and secondary creep behavior under shear stress lower or equal to the residual strength condition. Based on the data, a model for predicting the critical or failure time is introduced. The study traces the development of the limit state based on the contact model corresponding to Blair’s body. The time to occurrence of the conditions necessary for unlimited creep on the surface is estimated. As long-term precipitation and infiltrating water in the area of the landslides are identified as the key phenomena initiating collapse, the work focuses on the prediction of landslides with identified surfaces of potential damage as a result of changes in the saturation state. The procedure outlined is applied to a case study and considerations as to when the necessary safety work should be carried out are presented.

The Creep Behavior of a Floating Beam

1983 ◽  
Vol 27 (04) ◽  
pp. 271-280
Author(s):  
Paul C. Xirouchakis
Keyword(s):  
Cross Section ◽  
Creep Behavior ◽  
Failure Time ◽  
Failure Criteria ◽  
Secondary Creep ◽  
Nonlinear Creep ◽  
Double Membrane ◽  
Creep Response ◽  
Distributed Load ◽  
Linear Viscoelastic

The creep response is obtained for an inhomogeneous beam, with simple end supports, resting on a liquid foundation and subjected to a sinusoidally distributed load. The Norton-Bailey constitutive equations are used to describe secondary creep behavior and elastic effects are retained. The liquid foundation is taken as a continuous Winkler support. The beam cross section is replaced by a double-membrane model. The implications are discussed of using stress or deflection failure criteria in determining the magnitude of the instantaneous breakthrough load. The linear viscoelastic as well as nonlinear creep beam response is obtained explicitly. The influence of the beam geometric and material characteristics and of the presence of the liquid foundation on the growth of the deflections with time is discussed. The variation of the breakthrough load with failure time is also explored. Results obtained are compared with available sea ice laboratory test data.

scholarly journals Methods for Fitting the Limit State Function of the Residual Strength of Damaged Ships

2022 ◽  
Vol 10 (1) ◽  
pp. 102
Author(s):  
Zhiyao Zhu ◽  
Huilong Ren ◽  
Xiuhuan Wang ◽  
Nan Zhao ◽  
Chenfeng Li
Keyword(s):  
Least Squares ◽  
Residual Strength ◽  
Least Squares Method ◽  
Limit State ◽  
Nonlinear Least Squares ◽  
State Function ◽  
Limit State Function ◽  
Distribution Models ◽  
Sample Distribution ◽  
Fitting Method

The limit state function is important for the assessment of the longitudinal strength of damaged ships under combined bending moments in severe waves. As the limit state function cannot be obtained directly, the common approach is to calculate the results for the residual strength and approximate the limit state function by fitting, for which various methods have been proposed. In this study, four commonly used fitting methods are investigated: namely, the least-squares method, the moving least-squares method, the radial basis function neural network method, and the weighted piecewise fitting method. These fitting methods are adopted to fit the limit state functions of four typically sample distribution models as well as a damaged tanker and damaged bulk carrier. The residual strength of a damaged ship is obtained by an improved Smith method that accounts for the rotation of the neutral axis. Analysis of the results shows the accuracy of the linear least-squares method and nonlinear least-squares method, which are most commonly used by researchers, is relatively poor, while the weighted piecewise fitting method is the better choice for all investigated combined-bending conditions.

Nanoindentation creep behavior of enamel biological nanocomposites

RSC Advances ◽  
2014 ◽  
Vol 4 (77) ◽  
pp. 41003-41009 ◽  
Author(s):  
Jing Zhang ◽  
Chunbao Wang ◽  
Fan Yang ◽  
Chang Du
Keyword(s):  
External Force ◽  
Creep Test ◽  
Creep Behavior ◽  
Organic Matrix

Organic matrix and water are essential factors for enamel biological nanocomposite to resist external force as revealed by nanoindentation creep test.

On the Interrupted Creep Test Under Low Stress Levels for the Power Law Parameter Extraction

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Bin Yang ◽  
Fu-Zhen Xuan ◽  
Wen-Chun Jiang
Keyword(s):  
Creep Strain ◽  
Stress Level ◽  
Creep Test ◽  
Creep Deformation ◽  
Parameter Extraction ◽  
Tertiary Creep ◽  
Secondary Creep ◽  
Creep Stage ◽  
Strain Data

Abstract Low stress interrupted creep test, as an interim compromise, can provide essential data for creep deformation design. However, there are no clear guidelines on the characterization of the terminating time for interrupted low-stress creep test. To obtain a suitable terminating time in terms of economy and effectiveness, long-term creep strain data of 9%Cr steels are collected from literatures and their creep deformation characterization is analyzed. First, the variations of normalized time and strain of each creep stage with the stress level are discussed. Then, the effect of the terminating time on final fitted results of Norton–Bailey equation is estimated. Third, the relationship between demarcation points at different creep stages and minimum/steady-state creep rate is analyzed. The results indicate that when the creep rupture life is considered as an important factor for creep design, the tertiary creep stage is of greatest significance due to the largest life fraction and creep strain fraction at low stress level. However, the primary and secondary creep stages are of great significance for design due to their larger contribution to 1% limited creep strain. And the long-term secondary creep data could be extrapolated by combining the primary creep strain data obtained from interrupted creep tests with the time to onset of tertiary creep derived from a similar Monkman–Grant relationship.

Discrete Element Modelling of Rock Creep Behaviour using Rate Process Theory

2020 ◽  
Author(s):  
José G. Gutiérrez-Ch ◽  
Salvador Senent ◽  
Eduardo Estebanez ◽  
Rafael Jimenez
Keyword(s):  
Creep Behavior ◽  
Creep Behaviour ◽  
Element Model ◽  
Discrete Element ◽  
Process Theory ◽  
Discrete Element Modelling ◽  
Rate Process ◽  
Creep Tests ◽  
Rock Creep ◽  
Rate Process Theory

Rock creep behavior is crucial in many rock engineering projects. Different approaches have been proposed to model rock creep behavior; however, many cannot reproduce tertiary creep (i.e., accelerating strain rates leading to rock failure). In this work, a discrete element model (DEM) is employed, in conjunction with the rate process theory [Kuhn MR, Mitchel JK. Modelling of soil creep with the discrete element method. Eng Computations. 1992;9(2):277–287] to simulate rock creep. The DEM numerical sample is built using a mixture of contact models between particles that combines the Flat Joint Contact Model and the Linear Model. Laboratory uniaxial compression creep tests conducted on intact slate samples are used as a benchmark to validate the methodology. Results demonstrate that, when properly calibrated, DEM models combined with the rate process theory can reproduce all creep stages observed in slate rock samples in the laboratory, including and without using constitutive models that incorporate an explicit dependence of strain rate with time. The DEM results also suggest that creep is associated to damage in the samples during the laboratory tests, due to new micro-cracks that appear when the load is applied and maintained constant at each loading stage.

Creep property measurement of service-exposed SUS 316 austenitic stainless steel by the small-punch creep-testing technique

2002 ◽  
Vol 17 (8) ◽  
pp. 1945-1953 ◽  
Author(s):  
Maribel L. Saucedo-Muñoz ◽  
Shin-Ichi Komazaki ◽  
Toru Takahashi ◽  
Toshiyuki Hashida ◽  
Tetsuo Shoji
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Creep Test ◽  
Creep Resistance ◽  
Creep Property ◽  
Creep Rupture ◽  
Secondary Creep ◽  
Small Punch ◽  
Uniaxial Creep ◽  
Small Punch Creep Test

The creep properties for SUS 316 HTB austenitic stainless steel were evaluated by using the small-punch creep test at 650 °C for loads of 234, 286, 338, 408, and 478 N and at 700 °C for loads of 199 and 234 N. The creep curves, determined by means of the small-punch creep test, were similar to those obtained from a conventional uniaxial creep test. That is, they exhibited clearly the three creep stages. The width of secondary creep stage and rupture time tr decreased with the increase in testing load level. The creep rupture strength for the service-exposed material was lower than that of the as-received material at high testing loads. However, the creep resistance behavior was opposite at relatively low load levels. This difference in creep resistance was explained on the basis of the difference in the creep deformation and microstructural evolution during tests. It was also found that the ratio between the load of small-punch creep test and the stress of uniaxial creep test was about 1 for having the same value of creep rupture life.

On New Modifications of Some Strength Criteria for Anisotropic Materials

2016 ◽  
Vol 724 ◽  
pp. 53-57 ◽  
Author(s):  
S.L. Shambina ◽  
F.V. Rekach ◽  
Y.V. Belousov
Keyword(s):  
Limit State ◽  
Strength Criterion ◽  
Material Strength ◽  
Small Element ◽  
Exact Results ◽  
Strength Condition ◽  
Stress Space ◽  
Strength Criteria ◽  
State Of Stress ◽  
The Moment

The strength criterion is the strength condition for a small element of the construction’s material. Strength criterion is analytical interpretation in stress space the allowable boundaries of stress state, within these boundaries the material can work under these conditions without breaking. Since analytical interpretation of the experimental data may be performed in different ways, therefore many different strength criteria exist. Properly chosen strength criterion allows determining the moment when the material is destroyed while it is working under various tense conditions. Also it gives an opportunity to assess the limit state of stress in the most loaded points of the structure. This paper suggests new modifications of some well-known strength criteria which are more comfortable for practical use and can help to achieve more exact results.

scholarly journals Flexural creep behavior of structural insulated timber panels

2021 ◽  
Author(s):  
Mohammad Hossein Zarghooni
Keyword(s):  
Creep Test ◽  
Creep Behavior ◽  
Experimental Testing ◽  
Test Methods ◽  
Load Test ◽  
Test Results ◽  
Financing Costs ◽  
Wood Frame ◽  
Term Creep

A Structural Insulated Panel (SIP) is a panel composed of insulation core laminated between two oriented-strand boards (OSB). SIPs deliver building efficiencies by replacing several components of traditional residental and commercial construction, including: (i) studs; (ii) insulation; (iii) vapour barrier; and (iv) air barrier. A SIP-based structure offers superior insulation, exceptional strength, and fast installation. Besides those benefits, the total construction costs are less with SIPs compared to wood-framed homes, expecially when considering speed of construction, less expensive HVAC equipment required, reduced site waste, reduction construction financing costs, more favourable energy-efficient mortages available, and lower cost of owning a home built with SIPS. This thesis presents the experimental testing on selected SIP sizes to investigate their short- and long-term creep behavior under sustained loading. The experiment study performed in a manner to comply with applicable test methods and, Canadian Codes. Short-term creep test results showed the structural adequacy of the tested panels, while the long-term creep test results established the increase in panel total deflection with time. The ultimate load test results showed that the structural qualification of SIPs is "as good as" the structural capacity of the conventional wood-frame buildings.

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