Dynamically Loaded Journal Bearings: A Finite Element Treatment for Rigid and Elastic Surfaces

1985 ◽  
Vol 107 (4) ◽  
pp. 505-513 ◽  
Author(s):  
G. A. LaBouff ◽  
J. F. Booker

Hydrodynamic lubrication of dynamically loaded journal bearings with both rigid and flexible housings is treated by a unified computational procedure based on the finite element method. Numerical examples show effects of mesh density and housing flexibility under steady and periodic loading.

2013 ◽  
Vol 61 (1) ◽  
pp. 111-121 ◽  
Author(s):  
T. Jankowiak ◽  
T. Łodygowski

Abstract The paper considers the failure study of concrete structures loaded by the pressure wave due to detonation of an explosive material. In the paper two numerical methods are used and their efficiency and accuracy are compared. There are the Smoothed Particle Hydrodynamics (SPH) and the Finite Element Method (FEM). The numerical examples take into account the dynamic behaviour of concrete slab or a structure composed of two concrete slabs subjected to the blast impact coming from one side. The influence of reinforcement in the slab (1, 2 or 3 layers) is also presented and compared with a pure concrete one. The influence of mesh density for FEM and the influence of important parameters in SPH like a smoothing length or a particle distance on the quality of the results are discussed in the paper


Author(s):  
S. Boedo

This paper presents a hybrid mobility solution approach to the analysis of dynamically loaded misaligned journal bearings. Mobility data obtained for misaligned bearings (calculated from a finite element representation of the Reynolds equation) are compared with existing curve-fitted mobility maps representative of a perfectly aligned bearing. A relative error analysis of mobility magnitude and direction provides a set of misaligned journal bearing configurations (midplane eccentricity ratio and normalized misalignment angle) where existing curve-fitted mobility map components based on aligned bearings can be used to calculate the resulting journal motion. For bearing configurations where these mobility maps are not applicable, the numerical simulation process proceeds using a complete finite element solution of the Reynolds equation. A set of numerical examples representing misaligned main and connecting rod bearings in a four-stroke automotive engine illustrate the hybrid solution method. Substantial savings in computational time are obtained using the hybrid approach over the complete finite element solution method without loss of computational accuracy.


2012 ◽  
Vol 135 (2) ◽  
Author(s):  
S. Boedo

This paper presents a hybrid mobility solution approach to the analysis of dynamically loaded misaligned journal bearings. Mobility data obtained for misaligned bearings (calculated from a finite element representation of the Reynolds equation) are compared with existing curve-fitted mobility maps representative of a perfectly aligned bearing. A relative error analysis of mobility magnitude and direction provides a set of misaligned journal bearing configurations (midplane eccentricity ratio and normalized misalignment angle), where existing curve-fitted mobility map components based on aligned bearings can be used to calculate the resulting journal motion. For bearing configurations where these mobility maps are not applicable, the numerical simulation process proceeds using a complete finite element solution of the Reynolds equation. A numerical example representing a misaligned main bearing in a four-stroke automotive engine illustrates the hybrid solution method. Substantial savings in computational time are obtained using the hybrid approach over the complete finite element solution method without loss of computational accuracy.


2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
Li Tian ◽  
Dai Xiaoxia ◽  
Zhang Chengwei

We propose two algorithms for elliptic boundary value problems in shape optimization. With the finite element method, the optimization problem is replaced by a discrete variational problem. We give rules and use them to decide which elements are to be reserved. Those rules are determined by the optimization; as a result, we get the optimal design in shape. Numerical examples are provided to show the effectiveness of our algorithms.


1994 ◽  
Vol 116 (4) ◽  
pp. 698-704 ◽  
Author(s):  
D. Bonneau ◽  
J. Absi

A numerical study of gas herringbone grooved journal bearings is presented for small number of grooves. The compressible Reynolds equation is solved by use of the Finite Element Method. The nonlinearity of the discretized equations is treated with the Newton-Raphson procedure. A comparison of the results for a smooth bearing with previously published results is made and the domain of validity of the Narrow Groove Theory is analyzed. Load capacity, attitude angle, and stiffness coefficients are given for various configurations: groove angle and thickness of grooves, bearing number, and that for both smooth and grooved member rotating.


1978 ◽  
Vol 100 (4) ◽  
pp. 660-666 ◽  
Author(s):  
A. L. Salama ◽  
M. Petyt

The finite element method is used to study the free vibration of packets of blades. A packet of six shrouded blades is analyzed, only the tangential vibrations being considered. Results are obtained to establish the effect of certain parameters such as stiffness ratio, mass ratio, the number of blades in the packet, the effect of rotation and the position of the lacing wires. The dynamic response of a packet to periodic loading is also studied. The cases of engine order harmonic excitation and partial admission of gas are considered with reference to a packet of six shrouded blades.


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