The bearing behavior and failure characteristic of CFRP laminate with cutout under shearing load: Part II. Numerical simulations

2016 ◽  
Vol 141 ◽  
pp. 366-374 ◽  
Author(s):  
Xiaole Li ◽  
Weicheng Gao ◽  
Wei Liu
2006 ◽  
Vol 129 (1) ◽  
pp. 205-208 ◽  
Author(s):  
J. Bouyer ◽  
M. Fillon ◽  
I. Pierre-Danos

The behavior of the hydrodynamic journal bearings is now very well known because of the many experimental and numerical studies that have been carried out on the topic. This interest in two-lobe journal bearings is due to the fact that their simplicity, efficiency, and low cost have led to them being widely used in industry. These mechanical components tend to be subjected to numerous startups and stops. During transient periods, direct contact between the journal and bearing induces high friction in the lubricated contact and hence wear of the lining. The aim of this work is, first, to present experimental data obtained on a journal lobed bearing subjected to numerous starts and stops. Then, a comparison is made between the measured bearing performance and numerical results, these being obtained on the assumption that the regime is a thermohydrodynamic one. The wear after more than 2000 cycles was measured and used to generate numerical simulations. The aim here was to compare experimental data with theoretical results. It was observed that hydrodynamic pressure increases, whereas the temperature at the film/bush interface slightly decreases on both the upper and lower lobes. These trends are confirmed by the numerical simulations, with theoretical results being very close to experimental data. The final value for wear was measured, the maximum being found to be located at an angular coordinate of 180deg and reaching nearly 9μm. The present study demonstrates that, for the case studied, while the bearing behavior is clearly affected by wear, the bearing still remains useable and safe.


2010 ◽  
Vol 163-167 ◽  
pp. 3604-3609
Author(s):  
Yi Min Wu

Numerical simulations were conducted to investigate the bearing behaviour of steel foot pipe. Main mechanical affections occur at the lateral zone, and the maximal stress occurs at the lateral end of the pipe. With the increase of cross direction load, the maximal stress increases and exceeds the strength of material, and the pipe is pulled out. The influencing factors of bearing capacity of the steel foot pipe were studied. Some important results different from engineering experiences are as following: 1) to steel foot pipe that can not penetrate the soft base, its reasonable dip angle is very small for its low longitudinal bearing capacity; 2) steel pipe with diameter of 42mm is unsuitable for foot steel pipe because its low cross bearing capacity; 3) to a given geological condition and pipe parameter, the reasonable length of steel pipe is certain, extra longer pipes can’t obtain larger capacity; 4) surrounding rock near the support structure should be especially reinforced by drilling grouting holes along the whole steel pipe.


2020 ◽  
Vol 640 ◽  
pp. A53
Author(s):  
L. Löhnert ◽  
S. Krätschmer ◽  
A. G. Peeters

Here, we address the turbulent dynamics of the gravitational instability in accretion disks, retaining both radiative cooling and irradiation. Due to radiative cooling, the disk is unstable for all values of the Toomre parameter, and an accurate estimate of the maximum growth rate is derived analytically. A detailed study of the turbulent spectra shows a rapid decay with an azimuthal wave number stronger than ky−3, whereas the spectrum is more broad in the radial direction and shows a scaling in the range kx−3 to kx−2. The radial component of the radial velocity profile consists of a superposition of shocks of different heights, and is similar to that found in Burgers’ turbulence. Assuming saturation occurs through nonlinear wave steepening leading to shock formation, we developed a mixing-length model in which the typical length scale is related to the average radial distance between shocks. Furthermore, since the numerical simulations show that linear drive is necessary in order to sustain turbulence, we used the growth rate of the most unstable mode to estimate the typical timescale. The mixing-length model that was obtained agrees well with numerical simulations. The model gives an analytic expression for the turbulent viscosity as a function of the Toomre parameter and cooling time. It predicts that relevant values of α = 10−3 can be obtained in disks that have a Toomre parameter as high as Q ≈ 10.


2007 ◽  
Vol 17 (4) ◽  
pp. 347-380 ◽  
Author(s):  
Mohammad P. Fard ◽  
Denise Levesque ◽  
Stuart Morrison ◽  
Nasser Ashgriz ◽  
J. Mostaghimi

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