Topic
Stress concentration
About: Stress concentration is a research topic. Over the lifetime, 23250 publications have been published within this topic receiving 422911 citations.
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25 May 2005-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, the quantitative relationship between notch tensile strength and diffusible hydrogen content has been investigated for the AISI 4135 steel at 1320 MPa by means of a slow strain rate test on circumferentially notched round bar specimens with stress concentration factors of 2.1, 3.3 and 4.9.
Abstract: The quantitative relationship between notch tensile strength and diffusible hydrogen content has been investigated for the AISI 4135 steel at 1320 MPa. The notch tensile strength was obtained by means of a slow strain rate test on circumferentially notched round bar specimens with stress concentration factors of 2.1, 3.3 and 4.9 after hydrogen charging, and the diffusible hydrogen content was then measured by thermal desorption spectrometry analysis. The diffusible hydrogen has been found to decrease the notch tensile strength in a power law manner, and the decrease is more prominent at a higher stress concentration factor. The finite element analysis results of stress and hydrogen distributions in the vicinity of the notch root have shown that the local fracture stress decreases with increasing local hydrogen concentration as the diffusible hydrogen content or stress concentration factor increases, resulting in the decrease in the notch tensile strength.
188 citations
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TL;DR: The effects of hypertension on the stress and strain distributions through the wall thickness were studied in the rat thoracic aorta and indicate that the aortic wall adapts itself to the mechanical field by changing not only the wall dimensions but also the residual stresses.
Abstract: The effects of hypertension on the stress and strain distributions through the wall thickness were studied in the rat thoracic aorta. Goldblatt hypertension was induced by constricting the left renal artery for 8 weeks. Static pressure-diameter-axial force relations were determined on excised tubular segments. The segments were then sliced into thin ring specimens. Circumferential strain distributions were determined from the cross-sectional shape of the ring specimens observed before and after releasing residual stresses by radial cutting. Stress distributions were calculated using a logarithmic type of strain energy density function. The wall thickness at the systolic blood pressure, P sys , significantly correlated with P sys . The mean stress and strain developed by P sys in the circumferential direction were not significantly different between the hypertensive and control aortas, while those in the axial direction were significantly smaller in the hypertensive aorta than in the control. The opening angles of the stress-free ring specimens correlated well with P sys . The stress concentration factor in the circumferential direction was almost constant and independent of P sys , although the stress distributions were not uniform through the wall thickness. Histological observation showed that the wall thickening caused by hypertension is mainly due to the hypertrophy of the lamellar units of the media, especially in the sub-intimal layer where the stress increase developed by hypertension is larger than in the other layers. These results indicate that: (a) the aortic wall adapts itself to the mechanical field by changing not only the wall dimensions but also the residual stresses, (b) this adaptation is primarily related to the circumferential stress but not to the axial stress, and (c) the aortic smooth muscle cells seem to change their morphology in response to the mechanical stress.
188 citations
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TL;DR: In this article, a spatial rescaling has been used to reduce the orthotropic problems to equivalent problems in materials with cubic symmetry, and solutions for orthotropic materials can be constructed approximately from isotropic material solutions or rigorously from cubic ones.
187 citations
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01 Jun 1988
TL;DR: In this paper, a statistical approach to crack closure determination, the crack closure behavior of surface cracks under pure bending, closure measurements on short fatigue cracks, and crack closure under plane strain conditions.
Abstract: Papers are presented on plasticity induced crack closure, crack closure in fatigue crack growth, the dependence of crack closure on fatigue loading variables, and a procedure for standardizing crack closure levels. Also considered are a statistical approach to crack closure determination, the crack closure behavior of surface cracks under pure bending, closure measurements on short fatigue cracks, and crack closure under plane strain conditions. Other topics include fatigue crack closure behavior at high stress ratios, the use of acoustic waves for the characterization of closed fatigue cracks, and the influence of fatigue crack wake length and state of stress on crack closure.
186 citations
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TL;DR: In this article, the authors examined the effect of specimen size on the axial compressive strength of IM7/8552 carbon fiber/epoxy unidirectional laminates.
186 citations