Measurements and Correlations of Slider Vibrations and Wear

1999 ◽  
Vol 122 (1) ◽  
pp. 374-380 ◽  
Author(s):  
M. D. Bryant ◽  
David York

Studies have shown that micro-vibrations (10–100 μm amplitude, 10 to 100 Hz) of a slider can reduce sliding wear 50 percent, especially rigid body rocking motions that continuously realign the slider face with respect to the counter surface. In this article, clearances between a carbon sample and its holder were varied while sliding over a slightly wavy (8 to 20 μm) steel surface. Undulations on the counter surface induced rigid body vibrations of the slider. Clearances between sample and holder kinematically restricted rigid body rocking motions of the slider: larger clearances permitted more rocking. Measured were motions of the slider, including translations normal to the counter surface, and rotations about axes parallel to the counter surface. Time traces of these displacements were plotted at different sliding speeds. Frequency content and kinetic energies for each measured degree of freedom and the total were extracted. We sought correlations between measured wear and vibration data. Fractional changes in wear rate versus fractional changes in total kinetic energy clustered about a straight line. From these measurements, we found a quantitative relationship between amount of wear and total kinetic energy of vibration. [S0742-4787(00)05001-3]

Author(s):  
Guangbo Hao ◽  
Xianwen Kong ◽  
Xiuyun He

A planar reconfigurable linear (also rectilinear) rigid-body motion linkage (RLRBML) with two operation modes, that is, linear rigid-body motion mode and lockup mode, is presented using only R (revolute) joints. The RLRBML does not require disassembly and external intervention to implement multi-task requirements. It is created via combining a Robert’s linkage and a double parallelogram linkage (with equal lengths of rocker links) arranged in parallel, which can convert a limited circular motion to a linear rigid-body motion without any reference guide way. This linear rigid-body motion is achieved since the double parallelogram linkage can guarantee the translation of the motion stage, and Robert’s linkage ensures the approximate straight line motion of its pivot joint connecting to the double parallelogram linkage. This novel RLRBML is under the linear rigid-body motion mode if the four rocker links in the double parallelogram linkage are not parallel. The motion stage is in the lockup mode if all of the four rocker links in the double parallelogram linkage are kept parallel in a tilted position (but the inner/outer two rocker links are still parallel). In the lockup mode, the motion stage of the RLRBML is prohibited from moving even under power off, but the double parallelogram linkage is still moveable for its own rotation application. It is noted that further RLRBMLs can be obtained from the above RLRBML by replacing Robert’s linkage with any other straight line motion linkage (such as Watt’s linkage). Additionally, a compact RLRBML and two single-mode linear rigid-body motion linkages are presented.


1986 ◽  
Vol 01 (06) ◽  
pp. 377-381 ◽  
Author(s):  
K. DEPTA ◽  
J.A. MARUHN ◽  
W. GREINER ◽  
W. SCHEID ◽  
A. SANDULESCU

Within the 2-center shell model we present an explanation for the mass and total-kinetic-energy distributions of fission products of very heavy nuclei called “bimodal fission.” For the case of 258 FM we show that the symmetric fission can be described by a 2-dimensional treatment of the elongation and neck degree of freedom. Owing to shell corrections the system fissions via two decay channels that have distinct kinetic energies.


1976 ◽  
Vol 98 (3) ◽  
pp. 447-452
Author(s):  
P. North

The performance of many fluid flow devices is limited by the separation of the turbulent boundary layer. This separation may be suppressed or delayed by use of wall jets, raising questions of jet location and strength. A numerical analysis of a single wall jet gave results in close agreement with experiment. The same analysis of a single wall jet gave results in close agreement with experiment. The same calculation procedure indicated that two sequential wall jets, with the same total kinetic energy flux as the single jet, would suppress separation under conditions where the single jet would not. The best two-jet arrangement would be achieved with 63 percent of the total kinetic energy flux in the first jet. It is possible that three-jet arrangements could provide some further improvement.


2016 ◽  
Vol 194 ◽  
pp. 81-94 ◽  
Author(s):  
Dmitry V. Makhov ◽  
Todd J. Martinez ◽  
Dmitrii V. Shalashilin

We present an account of our recent effort to improve simulation of the photodissociation of small heteroaromatic molecules using the Ab Initio Multiple Cloning (AIMC) algorithm. The ultimate goal is to create a quantitative and converged technique for fully quantum simulations which treats both electrons and nuclei on a fully quantum level. We calculate and analyse the total kinetic energy release (TKER) spectra and Velocity Map Images (VMI), and compare the results directly with experimental measurements. In this work, we perform new extensive calculations using an improved AIMC algorithm that now takes into account the tunnelling of hydrogen atoms. This can play an extremely important role in photodissociation dynamics.


2020 ◽  
Vol 30 (6) ◽  
pp. 3199-3233 ◽  
Author(s):  
Cristian Guillermo Gebhardt ◽  
Ignacio Romero

Abstract This work proposes and investigates a new model of the rotating rigid body based on the non-twisting frame. Such a frame consists of three mutually orthogonal unit vectors whose rotation rate around one of the three axis remains zero at all times and, thus, is represented by a nonholonomic restriction. Then, the corresponding Lagrange–D’Alembert equations are formulated by employing two descriptions, the first one relying on rotations and a splitting approach, and the second one relying on constrained directors. For vanishing external moments, we prove that the new model possesses conservation laws, i.e., the kinetic energy and two nonholonomic momenta that substantially differ from the holonomic momenta preserved by the standard rigid body model. Additionally, we propose a new specialization of a class of energy–momentum integration schemes that exactly preserves the kinetic energy and the nonholonomic momenta replicating the continuous counterpart. Finally, we present numerical results that show the excellent conservation properties as well as the accuracy for the time-discretized governing equations.


2017 ◽  
Author(s):  
Daniel James Higgins ◽  
Kyle Thomas Schmitt ◽  
Shea Morgan Mosby ◽  
Fredrik Tovesson

2013 ◽  
Vol 22 (7) ◽  
pp. 075022 ◽  
Author(s):  
Stephen P Beeby ◽  
Leran Wang ◽  
Dibin Zhu ◽  
Alex S Weddell ◽  
Geoff V Merrett ◽  
...  

2012 ◽  
Vol 8 (S292) ◽  
pp. 47-47
Author(s):  
Huixian Li ◽  
Di Li ◽  
Rendong Nan

AbstractWe collected 27 outflows from the literature and found 8 new ones in the FCRAO CO maps of the Taurus molecular cloud. The total kinetic energy of the 35 outflows is found to be about 3% of the gravitational potential energy from the whole cloud. The feedback effect due to the outflows is minor in Taurus.


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