Estimation of Creep Deformation in Components From Short-Term Proof Test Data

1983 ◽  
Vol 105 (2) ◽  
pp. 179-184
Author(s):  
D. L. Marriott
Keyword(s):  
Experimental Data ◽  
Test Data ◽  
Stress Level ◽  
Creep Deformation ◽  
Short Term ◽  
Design Procedures ◽  
General Stress ◽  
Reference Stress

The paper describes a technique for estimating creep deformation from the results of short-term proof tests. The method relies on the concept of a reference stress which is representative of the general stress level in the component. It is shown that the method provides an upper, and therefore safe, bound on creep deformation. Application to a complex piping component is used to illustrate the procedure and some of the practical problems of interpreting the experimental data. Finally, an attempt is made to relate the reference stress method to tentative design procedures in Code Case N.47 of the ASME III Code.

scholarly journals Experimental Study on the Short-Term Uniaxial Creep Characteristics of Sandstone-Coal Composite Samples

Minerals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1398
Author(s):  
Dawei Yin ◽  
Feng Wang ◽  
Jicheng Zhang ◽  
Faxin Li ◽  
Chun Zhu ◽  
...  
Keyword(s):  
Creep Strain ◽  
Stress Level ◽  
Creep Strength ◽  
Creep Deformation ◽  
Shear Failure ◽  
Composite Sample ◽  
Short Term ◽  
Creep Failure ◽  
Creep Tests ◽  
Composite Samples

In this investigation, the uniaxial short-term creep tests with multi-step loading were conducted on the sandstone-coal composite samples, and the characteristics of creep strength, creep deformation, acoustic emission (AE), and creep failure of composite samples were studied, respectively. The creep strength of the composite sample decreased with the stress-level duration, which was mainly determined by the coal and influenced by the interactions with the sandstone. The creep deformation and damage of sandstone weakened the deformation and damage accumulation within the coal, resulting in the larger strength for the composite sample compared with the pure coal sample. The axial creep strain of composite sample generally increased with the stress-level or the stress-level duration under same conditions. The AE characteristics of composite sample were related to the creep strain rate, the stress level, the stress level duration, and the local failure or fracture during creep loading. The micro or macro failure and fracture within the composite sample caused the rise in the axial creep strains and the frequency and intensity of AE signals, especially the macro failure and fracture. The creep failures of composite samples mainly occurred within the coal with the splitting ejection failure accompanied by the local shear failure, and no obvious failures were found within the sandstone. The coal in the composite sample became more broken with the stress-level duration.

Uniaxial Ratchetting of Filled Rubber: Experiments and Damage-Coupled Hyper-Viscoelastic-Plastic Constitutive Model

2018 ◽  
Vol 85 (6) ◽  
Author(s):  
Yifu Chen ◽  
Guozheng Kang ◽  
Jianghong Yuan ◽  
Chao Yu
Keyword(s):  
Experimental Data ◽  
Constitutive Model ◽  
Applied Stress ◽  
Stress Level ◽  
Cyclic Deformation ◽  
Room Temperature ◽  
Tensile Deformation ◽  
Accumulated Damage ◽  
Filled Rubber ◽  
Cyclic Tension

A series of stress-controlled uniaxial cyclic tension-unloading tests are discussed to investigate the ratchetting of a filled rubber at room temperature. It is shown that obvious ratchetting occurs and depends apparently on the applied stress level, stress rate, and stress history. Based on the experimental observations, a damage-coupled hyper-viscoelastic-plastic constitutive model is then developed to describe the ratchetting of the filled rubber, which consists of three branches in parallel, i.e., a hyperelastic, a viscoelastic, and a plastic one. The damage is assumed to act equally on three branches and consists of two parts, i.e., the Mullins-type damage caused by the initial tensile deformation and the accumulated damage occurred during the cyclic deformation. The developed model is validated by comparing the predicted results with the experimental data.

The Study of Creep and Deformation Properties of Sulfur-Containing Arbolit Exposed to Various Compression Stresses

2021 ◽  
Vol 899 ◽  
pp. 137-143
Author(s):  
Yulia A. Sokolova ◽  
Marina A. Akulova ◽  
Baizak R. Isakulov ◽  
Alla G. Sokolova ◽  
Berikbay B. Kul’sharov ◽  
...  
Keyword(s):  
Stress Level ◽  
Creep Deformation ◽  
Building Materials ◽  
Physical And Mechanical Properties ◽  
High Strength ◽  
Experimental Tests ◽  
Theory And Practice ◽  
Wall Material ◽  
Deformation Properties ◽  
Sulfur Containing

The present paper considers the study of creep and deformation properties of sulfur-containing arbolit exposed to various compression stresses. Investigating the creep of lightweight arbolit concretes greatly affecting the performance of bearing and envelope structures draws a special attention during the last years. This issue is of particular relevance in the regions with hot and sharp continental climate. Arbolit concrete is one of the lightest building materials with low thermal conductivity and good soundproof properties. The modern postulates of theory and practice of creation, development of high-strength arbolit concretes on the base of composite sulfur-containing binders have become the methodological framework of the present research. While carrying out scientific research, the following standard measuring and analysis methods of physical and mechanical properties have been used for sulfur-containing arbolit composites. Experimental tests have been implemented on the 28-days samples made of sulfur-containing arbolit, with the cotton plant footstalks as an organic component. The researched samples were vapor sealed with the purpose to eliminate overlapping the processes of contraction and creep. The experimental results have shown that the analysis of prisms deformation in time demonstrates certain derivation from the pattern. Deformation of prisms made of sulfur-containing arbolit loaded at the low stress level were growing at a slower rate that the same deformations at a higher stress level. No derivation has been observed for the prisms of sulfur-containing haydite concrete. For both types of concrete, creep deformation has reached the values exceeding completely recoverable deformation by a factor of 2 or all the samples, the rapid growth of creep deformation has been observed after loading, followed by the gradual slowdown of deformation growth. For sulfur-containing lightweight concretes, as the test shown, the rate of creep deformation growth depends on the hardening curve in time reflecting the process of concrete hardening. This, if compared with sulfur-containing lightweight concretes, creep of sulfur-containing arbolit concrete is significantly lower that eventually leads to the loss of creep deformation at the same stress level. The obtained results can be used when manufacturing an efficient wall material for residential construction, including seismic areas.

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