Stiffness and Friction Force Measurements on a Freight Car Truck from Quasi-Static Tests

1984 ◽  
Vol 106 (1) ◽  
pp. 16-20 ◽  
Author(s):  
G. Kachadourian ◽  
C. L. Orth ◽  
D. W. Inskeep
Keyword(s):  
Friction Force ◽  
The Body ◽  
Load Application ◽  
Force Measurements ◽  
Friction Forces ◽  
Static Tests ◽  
Bearing Contact ◽  
Freight Car ◽  
Force Data ◽  
Fixed Section

A conventional three-piece truck with load sensitive friction snubbing was tested as a complete assembly with its wheels resting on a fixed section of rail and with loads applied through a fixture that duplicated the body bolster at the truck bolster interface. The purpose of the testing was to determine the stiffness and friction forces of the truck under vertical, lateral, and roll moment loading conditions. Loads were varied to cover a range of car gross weight conditions. The test was quasi-static in that load application was varied at sinusoidal rates of 0.1 or 0.2 Hertz to minimize errors in spring rate measurement caused by friction snubber forces. The desired stiffness and friction force data were obtained in terms of system rather than component properties and are consequently more directly usable in mathematical models. The roll test data were particularly useful because separate spring rates were obtained for the different conditions of center plate seated, center plate rocking, and side bearing contact. Because of the sinusoidal method of load application, it was possible to obtain system spring rates with the friction snubbers static and sliding.

Friction Force Measurements Using the Instantaneous IMEP Method and Comparison With RINGPAK Simulations

2005 ◽  
Author(s):  
Myoungjin Kim ◽  
Thomas M. Kiehne ◽  
Ronald D. Matthews
Keyword(s):  
Friction Force ◽  
Piston Ring ◽  
Cost Effective ◽  
Firing Condition ◽  
Force Measurements ◽  
Connecting Rod ◽  
Friction Forces ◽  
Bench Tests ◽  
Ring Assembly ◽  
Analysis System

Even though many researchers have measured the piston/ring assembly friction force over the last several decades, accurate measurement of the piston/ring assembly friction force is a still challenging problem. The floating liner method is not widely used, in spite of its accuracy, due to the substantial modifications required to the engine. On the other extreme, bench tests of the piston/ring assembly cannot completely simulate the real firing condition although bench tests are rapid, consistent, and cost effective. In this study, friction forces of the piston/ring assembly were measured using the instantaneous IMEP method and compared with modeling results using Ricardo’s RINGPAK software. In this research, a flexible flat cable was used to connect the connecting rod strain gage signal to the analysis system instead of using a grasshopper linkage. Therefore, the piston/ring assembly friction force was measured with the minimum change to the engine hardware.

Experimental Study of Friction in a Pneumatic Actuator at Constant Velocity

1993 ◽  
Vol 115 (3) ◽  
pp. 575-577 ◽  
Author(s):  
Lee E. Schroeder ◽  
Rajendra Singh
Keyword(s):  
Experimental Study ◽  
Experimental Method ◽  
Friction Force ◽  
Constant Velocity ◽  
Sliding Friction ◽  
Pneumatic Actuator ◽  
Friction Forces ◽  
Friction Models ◽  
Semi Empirical ◽  
Force Data

This paper describes an experimental method of determining sliding friction forces in a pneumatic actuator. Several empirical and semi-empirical friction models are evaluated using measured friction force data. A repeatability study is also performed to qualitatively assess friction randomness and a change in friction regimes.

Friction measurement and correction method in quasi-static tests of columns under combined axial and cyclic lateral loading

2019 ◽  
Vol 22 (12) ◽  
pp. 2672-2686
Author(s):  
Zeyuan Wang ◽  
Peng Feng ◽  
Shi Cheng ◽  
Tao Yu
Keyword(s):  
Friction Force ◽  
Force Measurement ◽  
Reaction Force ◽  
Lateral Force ◽  
Correction Method ◽  
Friction Measurement ◽  
Measurement Device ◽  
Friction Forces ◽  
Static Tests ◽  
Lateral Friction

In quasi-static tests of large-scale structural columns and/or columns under large axial loads, the lateral friction force between the column and the loading system can become a significant problem: they may cause considerable deviation between the measured lateral force and the actual reaction force of the column, especially under large axial compression load. Many researchers have come up with different methods to reduce or eliminate the influence of such friction force. In this article, previous treatments on the lateral friction force in quasi-static tests are first discussed. A shear force measurement device, for accurate measurement of the friction force, is then presented and calibrated. Based on the friction forces measured by the device in real tests, a simple model is proposed to predict the lateral friction force in quasi-static tests. Using the model, the measured lateral force in such tests can be corrected to obtain the actual reaction force of the column when a friction measurement device is absent. The proposed model and the correction method are then validated using results from several previous tests.

Atomic-Scale Friction Measurements Using Friction Force Microscopy: Part I—General Principles and New Measurement Techniques

1994 ◽  
Vol 116 (2) ◽  
pp. 378-388 ◽  
Author(s):  
Ju-Ai Ruan ◽  
Bharat Bhushan
Keyword(s):  
Friction Force ◽  
Microelectromechanical Systems ◽  
Atomic Scale ◽  
Magnetic Storage ◽  
Basic Operation ◽  
Friction Force Microscopy ◽  
Force Measurements ◽  
Friction Forces ◽  
Force Microscopy ◽  
Friction Measurements

Friction force measurements using modified atomic force microscopy, called here Friction Force Microscopy (FFM), are becoming increasingly important in the understanding of fundamental mechanisms of friction, wear, and lubrication, and to study interfacial phenomena in micro- and nanostructures used in magnetic storage systems and Microelectromechanical Systems (MEMS). FFMs can be used to study engineering surfaces in dry or wet conditions. A review of existing designs of FFMs and methods of friction force measurements is presented. In terms of friction force measurements, there are important issues related to the basic operation and calibration of these instruments which have not been fully studied. A new method of measuring friction fore using a commercial FFM and a calibration procedure for conversion of measured data to normal and friction forces are presented. Microscale friction data of selected materials are presented and discussed in light of macro-friction measurements.

scholarly journals CAN THE FRICTION FORCE BE THE DRIVING FORCE?

2020 ◽  
Vol 71 (3) ◽  
pp. 111-117
Author(s):  
L.G. Kassenov ◽  
◽  
B.H. Zhanbusinova ◽  
S.S. Sagintayev ◽  
◽  
...  
Keyword(s):  
Friction Force ◽  
Dry Friction ◽  
Driving Force ◽  
Materials Science ◽  
The Body ◽  
Friction Forces ◽  
Maximum Value ◽  
Physical Materials ◽  
Two Bodies

Friction is one of the types of interaction between bodies. It occurs when two bodies touch. The forces acting between the surfaces of contacting solids are called dry friction forces. They are always directed tangentially to the touching surfaces and are divided into the forces of friction at rest, sliding and rolling. The friction forces depend on many factors that accompany the movement of bodies in the presence of friction. In this regard, the description of friction forces is possible only with the help of empirically found approximate laws, which are often quite rough. The rest friction force is a variable value, it can change from zero to a certain maximum value. By applying a force to the body that exceeds the maximum resting friction force, we will move the body from its place, and it will begin to move. The article considers examples of motion in which the friction force can be mistakenly interpreted as a driving force. The nature of the forces of friction at rest and rolling is considered from the perspective of modern physical materials science.

scholarly journals Influence of Nanoscale Textured Surfaces and Subsurface Defects on Friction Behaviors by Molecular Dynamics Simulation

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1617 ◽  
Author(s):  
Ruiting Tong ◽  
Zefen Quan ◽  
Yangdong Zhao ◽  
Bin Han ◽  
Geng Liu
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Friction Force ◽  
Copper Substrate ◽  
Dynamics Simulation ◽  
Textured Surfaces ◽  
Friction Forces ◽  
Subsurface Structures ◽  
Texture Orientation ◽  
Subsurface Defects

In nanomaterials, the surface or the subsurface structures influence the friction behaviors greatly. In this work, nanoscale friction behaviors between a rigid cylinder tip and a single crystal copper substrate are studied by molecular dynamics simulation. Nanoscale textured surfaces are modeled on the surface of the substrate to represent the surface structures, and the spacings between textures are seen as defects on the surface. Nano-defects are prepared at the subsurface of the substrate. The effects of depth, orientation, width and shape of textured surfaces on the average friction forces are investigated, and the influence of subsurface defects in the substrate is also studied. Compared with the smooth surface, textured surfaces can improve friction behaviors effectively. The textured surfaces with a greater depth or smaller width lead to lower friction forces. The surface with 45° texture orientation produces the lowest average friction force among all the orientations. The influence of the shape is slight, and the v-shape shows a lower average friction force. Besides, the subsurface defects in the substrate make the sliding process unstable and the influence of subsurface defects on friction forces is sensitive to their positions.

Maximizing the efficiency of a flexible propulsor using experimental optimization

2015 ◽  
Vol 767 ◽  
pp. 430-448 ◽  
Author(s):  
Daniel B. Quinn ◽  
George V. Lauder ◽  
Alexander J. Smits
Keyword(s):  
Leading Edge ◽  
The Body ◽  
Phase Lag ◽  
Force Measurements ◽  
Experimental Optimization ◽  
Image Velocimetry ◽  
Flexible Panel ◽  
Gradient Based ◽  
Power Scale ◽  
Effective Angle

AbstractExperimental gradient-based optimization is used to maximize the propulsive efficiency of a heaving and pitching flexible panel. Optimum and near-optimum conditions are studied via direct force measurements and particle image velocimetry (PIV). The net thrust and power scale predictably with the frequency and amplitude of the leading edge, but the efficiency shows a complex multimodal response. Optimum pitch and heave motions are found to produce nearly twice the efficiencies of optimum heave-only motions. Efficiency is globally optimized when (i) the Strouhal number is within an optimal range that varies weakly with amplitude and boundary conditions; (ii) the panel is actuated at a resonant frequency of the fluid–panel system; (iii) heave amplitude is tuned such that trailing-edge amplitude is maximized while the flow along the body remains attached; and (iv) the maximum pitch angle and phase lag are chosen so that the effective angle of attack is minimized. The multi-dimensionality and multi-modality of the efficiency response demonstrate that experimental optimization is well-suited for the design of flexible underwater propulsors.

Friction of outer rotor affecting friction torque characteristics in an internal gear pump

2014 ◽  
Vol 229 (16) ◽  
pp. 3013-3026 ◽  
Author(s):  
Yoshiharu Inaguma
Keyword(s):  
Pressure Distribution ◽  
Friction Force ◽  
Significant Loss ◽  
Friction Torque ◽  
The Body ◽  
Gear Pump ◽  
Suction Pressure ◽  
Outer Rotor ◽  
Internal Gear ◽  
Outer Circumference

This article presents the friction torque in an internal gear pump and the friction force between an outer circumference of an outer rotor and a body, which causes a significant loss, has been investigated. When in use at a high pressure, the pump has a large friction torque due to the friction force acting on the outer rotor circumference. This friction force is caused by imbalanced force acting on the outer rotor. As well as by a positioning suction and a delivery port, the force can be reduced by setting a suction pressure recess in a section of the outer rotor circumference. In this study, through the measurement of the friction torque in an actual pump and the pressure distribution on the outer circumference of the outer rotor, it is investigated how the suction pressure recess can change the force acting on the outer rotor. The actual internal gear pump without the suction pressure recess has a large friction torque, and it corresponds to a large force on the outer rotor, which is calculated from the pressure distributions on the inside and outside of the outer rotor. In addition, on the basis of the measured friction torque of the test pump and the force acting on the outer rotor, calculated using the results of the pressure distribution, the coefficient of friction between the outer rotor circumference and the body can be estimated.

FORMATION OF EXPERIMENTAL AND METHODICAL BASIS TO ESTIMATE STRENGTH CORRESPONDENCE OF DOMESTIC PASSENGER CAR BODIES TO EUROPEAN STANDARD BASIS

2021 ◽  
Vol 2021 (8) ◽  
pp. 67-76
Author(s):  
Sergey Korshunov ◽  
Aleksandr Skachkov ◽  
Sergey Samoshkin ◽  
Aleksandr Smirnov ◽  
Dmitriy Goncharov
Keyword(s):  
International Markets ◽  
The Body ◽  
Standard Basis ◽  
Rolling Stock ◽  
European Standard ◽  
Static Tests ◽  
Railway Infrastructure ◽  
Methodical Basis ◽  
Equipment Development ◽  
European Standards

The development of the international trade and the entrance of domestic car manufacturers into international markets required bench equipment development for tests in accordance with the requirements of the European standards. In this connection the purpose of this work is to develop an experimental and methodical basis for the estimation of the strength correspondence of export railway produce to the European standard basis. In the work there is shown a description of the bench developed for static tests of rolling stock for loads corresponding to the European standard basis. In the requirements mentioned there is used a more extended list of loads and combination of efforts and the necessity in the application of longitudinal loads to the elements of the end wall in three levels should be particularly emphasized. On the test bench there are carried out static tests of the car of model 61-4514 for Egyptian national railways and the body of the motor-rail car of model 2853 for the railway infrastructure of Serbia.

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