Elastic waveguide propagation in an infinite isotropic solid cylinder that is subjected to a static axial stress and strain

1973 ◽  
Vol 53 (4) ◽  
pp. 1129-1133 ◽  
Author(s):  
G. Mott
Keyword(s):  
Axial Stress ◽  
Stress And Strain ◽  
Solid Cylinder ◽  
Elastic Waveguide ◽  
Waveguide Propagation ◽  
Isotropic Solid

Response of joint capsule neurons to axial stress and strain during dynamic loading in cat

1991 ◽  
Vol 65 (6) ◽  
pp. 1321-1328 ◽  
Author(s):  
M. S. Fuller ◽  
P. Grigg ◽  
A. H. Hoffman
Keyword(s):  
Gaussian Noise ◽  
Axial Stress ◽  
Correlation Coefficients ◽  
Input Function ◽  
Joint Capsule ◽  
Stress And Strain ◽  
Information Theoretic ◽  
Neural Discharge ◽  
Experimental Runs

1. Experiments were conducted to test the hypothesis that the responses of joint capsule mechanoreceptors better encode tissue stress or tissue strain. The experimental model was a small ligament from the cat knee capsule, which was stretched uniaxially in vitro. Experiments were done with either force or displacement as the controlled variable, and with steps, sinusoids, or pseudorandom Gaussian noise (PGN) as the input function. 2. The strength of coupling between neural discharge and both strain and stress was quantified during step experiments using linear correlation coefficients. The correlation between the frequency of neural discharge and stress was 0.93 +/- 0.09 (SD). The correlation between frequency of neural discharge and strain was -0.91 +/- 0.06. The magnitudes of these correlation coefficients were not significantly different. 3. The strength of coupling between neural discharge and both strain and stress during sinusoidal and PGN experiments was quantified by the use of an information theoretic statistic, transinformation. Out of 282 sinusoidal runs, transinformation between neural discharge and stress was significantly greater than transinformation between strain and neural discharge 241 times. Transinformation between strain and neural discharge was significantly greater 15 times. 4. During PGN experiments, transinformation between stress and neural discharge was greater than transinformation between strain and neural discharge in all 19 experimental runs. 5. Conditional transinformation between strain and neural discharge, given stress, was calculated for all sinusoidal and pseudorandom experiments. This statistic was greater than zero in 268 out of 289 experimental runs, indicating that a component of strain independent of stress is being signaled in the neural discharge.

Stress and Strain Distribution in Hypertensive and Normotensive Rat Aorta Considering Residual Strain

1996 ◽  
Vol 118 (1) ◽  
pp. 62-73 ◽  
Author(s):  
Takeo Matsumoto ◽  
Kozaburo Hayashi
Keyword(s):  
Residual Stresses ◽  
Wall Thickness ◽  
Axial Stress ◽  
Circumferential Stress ◽  
Circumferential Direction ◽  
Wall Thickening ◽  
Left Renal Artery ◽  
Stress And Strain ◽  
Stress Distributions ◽  
Cross Sectional

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, Psys, significantly correlated with Psys. The mean stress and strain developed by Psys 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 Psys. The stress concentration factor in the circumferential direction was almost constant and independent of Psys, 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 subintimal 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.

scholarly journals Permeability Prediction in Deep Coal Seam: A Case Study on the No. 3 Coal Seam of the Southern Qinshui Basin in China

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Pinkun Guo ◽  
Yuanping Cheng
Keyword(s):  
Coal Seam ◽  
Effective Stress ◽  
Axial Stress ◽  
Gas Pressure ◽  
Coal Bed ◽  
Stress And Strain ◽  
Qinshui Basin ◽  
Coal Permeability ◽  
Permeability Prediction ◽  
Southern Qinshui Basin

The coal permeability is an important parameter in mine methane control and coal bed methane (CBM) exploitation, which determines the practicability of methane extraction. Permeability prediction in deep coal seam plays a significant role in evaluating the practicability of CBM exploitation. The coal permeability depends on the coal fractures controlled by strata stress, gas pressure, and strata temperature which change with depth. The effect of the strata stress, gas pressure, and strata temperature on the coal (the coal matrix and fracture) under triaxial stress and strain conditions was studied. Then we got the change of coal porosity with strata stress, gas pressure, and strata temperature and established a coal permeability model under tri-axial stress and strain conditions. The permeability of the No. 3 coal seam of the Southern Qinshui Basin in China was predicted, which is consistent with that tested in the field. The effect of the sorption swelling on porosity (permeability) firstly increases rapidly and then slowly with the increase of depth. However, the effect of thermal expansion and effective stress compression on porosity (permeability) increases linearly with the increase of depth. The most effective way to improve the permeability in exploiting CBM or extracting methane is to reduce the effective stress.

scholarly journals Study on the Dynamic Response Characteristics of Cylindrical Coal-Rock Samples under Dynamic Loads

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Hongqing Zhu ◽  
Shuhao Fang ◽  
Yilong Zhang ◽  
Yan Wu
Keyword(s):  
Dynamic Response ◽  
Linear Relationship ◽  
Rock Sample ◽  
Axial Stress ◽  
Stress And Strain ◽  
Rock Samples ◽  
Response Characteristics ◽  
Coal Rock ◽  
Dynamic Response Characteristics ◽  
The Impact

To research the dynamic response characteristics of cylindrical coal-rock samples under impact loads, the impact of rigid bars on cylindrical coal-rock samples is simulated under different speed conditions, based on LS-DYNA software, and the dynamic distribution characteristics of the stress, strain, and energy of cylindrical coal-rock samples are analyzed. The results demonstrated the following: (1) the cylindrical coal-rock sample failed at the center first, and the damage developed downward along the axial direction. (2) The critical effective stress and strain have an exponential function relationship with the velocity, and the critical time has a linear relationship with the velocity. (3) The energy change law of the cylindrical coal-rock sample is consistent with the destruction morphology. (4) The axial stress peaks in the severe damage part have a linear relationship with the speed, the axial stress attenuates rapidly after passing the stress yield point, and the axial strain does not increase continuously. (5) The peaks stress and strain on the central axis and the radial line obey the power function distribution, the axial stress produces tensile stress in the axial propagation direction, and the axial stress and strain peaks at the same position are larger than those of the radial stress and strain peaks. This research provides a reference for studying coal and rock dynamic disasters.

Pipe Stress and Deflection During an Integrity Dig

2020 ◽  
Author(s):  
Ali Naderi ◽  
Ruoqi Deng ◽  
Deli Yu ◽  
Richard Kania ◽  
LePing Li
Keyword(s):  
Boundary Conditions ◽  
Axial Stress ◽  
Longitudinal Direction ◽  
Dominant Factor ◽  
Soil Conditions ◽  
Stress And Strain ◽  
Buried Pipeline ◽  
3D Elements ◽  
Circumferential Defects ◽  
Beam Theories

Abstract During a pipeline excavation, additional pipe stress and deflection can be produced due to altered soil support beneath the exposed pipe, which might bring in additional integrity concerns for the pipe under assessment. Classical beam theories and soil-spring modeling are inadequate for the complex pipe-soil interactions and boundary conditions. The objective of the present study was to develop a computational model that can be used to predict pipe stress and deflection during an integrity dig. The pipe-soil interaction was modeled with 3D elements using surface-to-surface contact approximation in ABAQUS. The pipe was assumed to be initially buried, then exposed for 12, 20, 30 and 34 m subsequently to mimic a buried pipeline under step-by-step excavation. The results indicated that the depth of soil support is a dominant factor for the pipe stress and deflection during an integrity excavation, which has not been previously investigated. Significant axial stress and strain in the longitudinal direction were produced by excavation, which may increase the risk of failure for the pipe that is suspected of circumferential defects. Furthermore, nonuniform soil support could cause substantial pipe deflections and stresses that may trigger an integrity dig. The model may be used to estimate the pipe stress and deflection prior to an integrity dig based on the soil conditions.

Thermal Stress Analysis of an FGM Cylinder under the Effect of Convection and Radially Varying Temperature Distribution

2009 ◽  
Vol 631-632 ◽  
pp. 23-28 ◽  
Author(s):  
Serra Topal ◽  
Mufit Gulgec
Keyword(s):  
Thermal Energy ◽  
Yield Criterion ◽  
Energy Generation ◽  
Functionally Graded ◽  
Stress And Strain ◽  
Solid Cylinder ◽  
Power Functions ◽  
Realistic Representation ◽  
Strain Components ◽  
Potential Applications

The plane strain problem for a functionally graded solid cylinder with thermal energy generation under the effect of convective heat transfer is considered. In previous studies on FGM cylinders in the literature, the modulus of elasticity, the thermal conductivity and the thermal expansion coefficient are represented by using either exponential or power functions. However, this study considers different functions for these material properties, which results in a more realistic representation of the problem. The stress and strain components are evaluated analytically and their dependencies on the radially varying material parameters are presented at the elastic state. Critical values of the volumetric thermal energy generation evaluated for a homogeneous solid cylinder and for an FGM cylinder are compared by using the Tresca’s Yield Criterion. Numerical results are generated by considering a W/Cu FGM solid cylinder which has potential applications as an International Thermonuclear Experimental Reactor (ITER) component.

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