The Influence of the Temperature Gradient near the Crack Surface on its Stability under Steady-State Thermomechanical Effects

2019 ◽  
Vol 974 ◽  
pp. 496-504
Author(s):  
V.V. Shevelev ◽  
L.M. Ozherelkova ◽  
I.R. Tishaeva
Keyword(s):  
Temperature Gradient ◽  
Brittle Fracture ◽  
Tensile Stress ◽  
Crack Surface ◽  
Circular Disk ◽  
Theory Of Elasticity ◽  
Uniaxial Tensile ◽  
Fracture Criteria ◽  
Uniaxial Tensile Stress ◽  
Brittle Fracture Criteria

The development of methods for predicting the reliability of structural elements based on brittle fracture criteria is a rather complex mathematical task. This is due to the fact that these criteria are usually obtained in the framework of the mathematical theory of cracks, the boundary problems of which allow a limited number of exact analytical solutions. To this we must add that the brittle fracture of materials with disc-shaped circular fractures has been studied in thermomechanics and in the kinetic theory of strength, from our point of view, is not enough and research in this area seems to be relevant to us. In this regard, in this work, within the framework of the linear theory of elasticity, two cases of external impact on a material containing a circular disk-shaped fracture are considered: mechanical, in the form of a uniaxial tensile stress, and temperature, in the form of a temperature gradient in the region of a material containing a circular disk-shaped crack destruction. From the extremum condition, brittle fracture criteria such as the Griffith criterion are obtained both for the case of only mechanical loading of the material with uniaxial tensile stress, and for the case of only temperature exposure of the material in the form of a local temperature gradient at the crack surface.

scholarly journals Verification of Brittle Fracture Criteria for Bimaterial Structures

2014 ◽  
Vol 8 (1) ◽  
pp. 44-48
Author(s):  
Grzegorz Mieczkowski ◽  
Krzysztof Molski
Keyword(s):  
Experimental Data ◽  
Composite Materials ◽  
Cyclic Loading ◽  
Brittle Fracture ◽  
Axial Loading ◽  
Loading Conditions ◽  
Fracture Criteria ◽  
Interfacial Cracks ◽  
Theoretical Results ◽  
Brittle Fracture Criteria

Abstract The increasing application of composite materials in the construction of machines causes strong need for modelling and evaluating their strength. There are many well known hypotheses used for homogeneous materials subjected to monotone and cyclic loading conditions, which have been verified experimentally by various authors. These hypotheses should be verified also for composite materials. This paper provides experimental and theoretical results of such verifications for bimaterial structures with interfacial cracks. Three well known fracture hypotheses of: Griffith, McClintock and Novozhilov were chosen. The theoretical critical load values arising from each hypotheses were compared with the experimental data including uni and multi-axial loading conditions. All tests were carried out with using specially prepared specimens of steel and PMMA.

scholarly journals Mechanical behaviour and structure of snow under uniaxial tensile stress

1980 ◽  
Vol 26 (94) ◽  
pp. 275-282 ◽  
Author(s):  
Hidek Narita
Keyword(s):  
Tensile Stress ◽  
Strain Rate ◽  
Mechanical Behaviour ◽  
Maximum Strength ◽  
Ductile Deformation ◽  
Uniaxial Tensile ◽  
Strain Rates ◽  
Thin Sections ◽  
Uniaxial Tensile Stress ◽  
Small Cracks

AbstractThe mechanical behaviour of snow was studied at — 10°C under uniaxial tensile stress in a range of cross-head speed 6.8 × 10–8to 3.1 × 10–4ms–1and snow density 240-470 kg m–3.It was found from the resisting force-deformation curves that the snow was deformed in two different ways: namely, brittle and ductile deformation at high and low strain-rates, respectively. The critical strain-rate dividing the two deformation modes was found to depend on the density of snow. In ductile deformation, many small cracks appeared throughout the entire specimen. Their features were observed by making thin sections and they were compared with small cracks formed in natural snow on a mountain slope.The maximum strength of snow was found to depend on strain-rate: at strain-rates above about 10–5s–1, the maximum strength increased with decreasing strain-rate but below 10–5s–1it decreased with decreasing strain-rate.

scholarly journals Mechanical behaviour and structure of snow under uniaxial tensile stress

1980 ◽  
Vol 26 (94) ◽  
pp. 275-282 ◽  
Author(s):  
Hidek Narita
Keyword(s):  
Tensile Stress ◽  
Strain Rate ◽  
Mechanical Behaviour ◽  
Maximum Strength ◽  
Ductile Deformation ◽  
Uniaxial Tensile ◽  
Strain Rates ◽  
Thin Sections ◽  
Uniaxial Tensile Stress ◽  
Small Cracks

AbstractThe mechanical behaviour of snow was studied at — 10°C under uniaxial tensile stress in a range of cross-head speed 6.8 × 10–8 to 3.1 × 10–4 ms–1 and snow density 240-470 kg m–3.It was found from the resisting force-deformation curves that the snow was deformed in two different ways: namely, brittle and ductile deformation at high and low strain-rates, respectively. The critical strain-rate dividing the two deformation modes was found to depend on the density of snow. In ductile deformation, many small cracks appeared throughout the entire specimen. Their features were observed by making thin sections and they were compared with small cracks formed in natural snow on a mountain slope.The maximum strength of snow was found to depend on strain-rate: at strain-rates above about 10–5 s –1, the maximum strength increased with decreasing strain-rate but below 10–5 s–1 it decreased with decreasing strain-rate.

The damage mechanism of 17vol.%SiCp/Al composite under uniaxial tensile stress

2020 ◽  
Vol 782 ◽  
pp. 139274 ◽  
Author(s):  
Qiuyan Shen ◽  
Zhanwei Yuan ◽  
Huan Liu ◽  
Xuemin Zhang ◽  
Qinqin Fu ◽  
...  
Keyword(s):  
Tensile Stress ◽  
Damage Mechanism ◽  
Uniaxial Tensile ◽  
Al Composite ◽  
Uniaxial Tensile Stress

scholarly journals Uniaxial Tensile Stress-Strain Relationships of RC Elements Strengthened with FRP Sheets

2016 ◽  
Vol 20 (3) ◽  
pp. 04015075 ◽  
Author(s):  
Guang Yang ◽  
Mehdi Zomorodian ◽  
Abdeldjelil Belarbi ◽  
Ashraf Ayoub
Keyword(s):  
Tensile Stress ◽  
Uniaxial Tensile ◽  
Stress Strain ◽  
Uniaxial Tensile Stress

Brittle Fracture Criteria Transferability Evaluation by Testing on Different Specimen Geometries

2008 ◽  
Author(s):  
S. Chapuliot ◽  
S. Marie
Keyword(s):  
Brittle Fracture ◽  
Critical Stress ◽  
Master Curve ◽  
Numerical Study ◽  
Fracture Criteria ◽  
Vessel Steel ◽  
Stress Criterion ◽  
Probability Of Fracture ◽  
Two Stages ◽  
Brittle Fracture Criteria

This paper describes an experimental and numerical study to assess the transposability of brittle fracture criteria from specimens of one type of geometry to another. The overall “master curve” approach, the Beremin model and a proposed model using the concept of critical stress were accordingly analysed. The experimental work supporting the analysis was made on 16MND5 reactor vessel steel. This was in the form of CT25 specimens, taken as the reference type, SENT specimens, ring specimens and CTpor specimens, which are CT specimens with a semi-elliptical surface defect. The analysis itself was made in two stages: the models were first calibrated on the basis of CT25 test results, then they were applied to specimens of other geometries. We then demonstrate that, in all cases, the models correctly replicated the variation of toughness (as measured on a CT25 specimen) with temperature. However, they all failed when applied to SENT and ring specimens, where calculation underestimates the probability of fracture. For CTpor specimens, the results are better, the master curve approach and the critical stress criterion give satisfactory results (but it has not yet been possible to apply the Beremin method). This paper concludes with a detailed analysis of the crack tip stress and strain fields, followed by an attempt to explain the differences between the different types of behaviour observed.

Sign in / Sign up

Export Citation Format

Share Document