A Comprehensive Fluid-Solid Interaction Analysis of Finite Journal Bearings

As key elements in plenty of rotating machinery, the elastohydrodynamic performance of journal bearings should be carefully checked in light of the design and operating parameters considered. This first part of the current study aims to numerically analyse the operation of journal bearings under alignment conditions. In the fluid-solid interaction analysis conducted, the lubricant flow field is solved using the finite volume method. Based on finite elements strategy, a structural analysis is then implemented to the solid bearing using the pressure distribution computed earlier on its inner surface. A wide range of operating conditions has been considered including the eccentricity ratio (0.1≤ε≤0.9), bearing length-diameter ratio (0.8≤L/D≤2), and rotation speed (4,000≤N≤10,000 rpm). Three principal categories of operational quantities have inspected, namely; the lubricant pressure distribution, overall performance parameters, and structural aftereffects. Among all the parameters examined, the eccentricity ratio is the most influential one on the performance of journal bearings. As it increases with applying heavier loads, a significant rise occurs in each of the friction force, power loss, stress levels, and deformation on the inner surface of the bearing. The bearing length and rotation speed, on the other hand, affect the bearing performance as well, but to a less extent

A Comprehensive Fluid-Solid Interaction Analysis of Finite Journal Bearings

As key elements in plenty of rotating machinery, the elastohydrodynamic performance of journal bearings should be carefully checked in light of the design and operating parameters considered. This first part of the current study aims to numerically analyse the operation of journal bearings under alignment conditions. In the fluid-solid interaction analysis conducted, the lubricant flow field is solved using the finite volume method. Based on finite elements strategy, a structural analysis is then implemented to the solid bearing using the pressure distribution computed earlier on its inner surface. A wide range of operating conditions has been considered including the eccentricity ratio (0.1≤ε≤0.9), bearing length-diameter ratio (0.8≤L/D≤2), and rotation speed (4,000≤N≤10,000 rpm). Three principal categories of operational quantities have inspected, namely; the lubricant pressure distribution, overall performance parameters, and structural aftereffects. Among all the parameters examined, the eccentricity ratio is the most influential one on the performance of journal bearings. As it increases with applying heavier loads, a significant rise occurs in each of the friction force, power loss, stress levels, and deformation on the inner surface of the bearing. The bearing length and rotation speed, on the other hand, affect the bearing performance as well, but to a less extent

Experimental and Numerical Study of Crack Effect on Frequency of Simple Supported Beam

In this research the natural frequency of a cracked simple supported beam (the crack is in many places and in different depths) is investigated analytically, experimentally and numerically by ANSYS program, and the results are compared. The beam is made of iron with dimensions of L*W*H= (0.84*0.02* 0.02m), and density = 7680kg/m3, E=200Gpa. A comparison made between analytical results from ANSYS with experimental results, where the biggest error percentage is about (7.2 %) in crack position (42 cm) and (6 mm) depth. Between Rayleigh method with experimental results the biggest error percentage is about (6.4 %) for the same crack position and depth. From the error percentages it could be concluded that the Rayleigh method gives close results to experimental than ANSYS. Also it is found that the frequency of beam when the crack is in the middle position is less than the frequency with crack near the end position

A COMPREHENSIVE FLUID-SOLID INTERACTION ANALYSIS OF FINITE JOURNAL BEARINGS

As key elements in plenty of rotating machinery, the elastohydrodynamic performance of journal bearings should be carefully checked in light of the design and operating parameters considered. This first part of the current study aims to numerically analyse the operation of journal bearings under alignment conditions. In the fluid-solid interaction analysis conducted, the lubricant flow field is solved using the finite volume method. Based on finite elements strategy, a structural analysis is then implemented to the solid bearing using the pressure distribution computed earlier on its inner surface. A wide range of operating conditions has been considered including the eccentricity ratio (0.1≤ε≤0.9), bearing length-diameter ratio (0.8≤L/D≤2), and rotation speed (4,000≤N≤10,000 rpm). Three principal categories of operational quantities have inspected, namely; the lubricant pressure distribution, overall performance parameters, and structural aftereffects. Among all the parameters examined, the eccentricity ratio is the most influential one on the performance of journal bearings. As it increases with applying heavier loads, a significant rise occurs in each of the friction force, power loss, stress levels, and deformation on the inner surface of the bearing. The bearing length and rotation speed, on the other hand, affect the bearing performance as well, but to a less extent.</jats:p

EFFECT OF NOTCH DIMENSION AND LOCATION ON FATIGUE LIFE AND THERMAL BEHAVIOR OF LOW CARBON STEEL (ST37-2)

The effect of depth and location of the notch on the v-notched specimen on fatigue life of cantilever rotating beam of low carbon steel (ST37-2) is studied, by applying fully reversed cycle load of 150 N, and mean stress of Zero. The temperature variations during fatigue life were measured by infrared camera at three points in specimens. These points are the edge point, notch point and other specified points. Numerically, the finite element model of fatigue test was obtained using the ANSYS Workbench. The ANSYS model was based on the S/N curve measured experimentally. From the results, there is a notch position that changed the fracture position from the notch position to the edge position. Also, fatigue life can be increased by putting the notch in appropriate position on the specimen. The temperature variation at different points in the specimen gave a good prediction to the fracture position before the fracture occurs. Also, from the comparison between experimental and numerical results, the two curves were similar but the ANSYS model based on the experimental S/N curve gave a good prediction for fatigue life