Effect of contact friction forces in compressive tests of specimens

1983 ◽  
Vol 15 (10) ◽  
pp. 1486-1487
Author(s):  
V. I. Koval' ◽  
Yu. B. Gnuchii ◽  
V. S. Morganyuk
Keyword(s):  
Contact Friction ◽  
Friction Forces ◽  
Compressive Tests

Dynamical Modeling of Gear Transmission Considering Gearbox Casing

2018 ◽  
Author(s):  
Yang Luo ◽  
Natalie Baddour ◽  
Ming Liang
Keyword(s):  
Dynamic Models ◽  
Signal Propagation ◽  
Gear Transmission ◽  
Gear System ◽  
Dynamical Model ◽  
Contact Friction ◽  
Dynamical Response ◽  
Dynamic Simulations ◽  
Friction Forces ◽  
Frequency Domains

Much research has been carried out to investigate the dynamical response of a gear system because of its importance on vibration feature analysis. It is well known that the gearbox casing is one of the most important components of the gear system and plays an important role in signal propagation. However, its effects have widely been neglected within the dynamic simulations and few dynamic models have considered the gearbox casing when modeling a gear transmission. This paper proposes a gear transmission dynamical model with the consideration of the effects of gearbox casing. The proposed dynamical model incorporates TVMS, a time-varying load sharing ratio, as well as dynamic tooth contact friction forces, friction moments and dynamic mesh damping coefficients. The proposed gear dynamical model is validated by comparison with responses obtained from experimental test rigs under different speed conditions. Comparisons indicate that the responses of the proposed dynamical model are consistent with experimental results, in both time and frequency domains under different rotation speeds.

Experimental Validation of a 2D Bristle Friction Force Model

2010 ◽  
Author(s):  
Steven Fillmore ◽  
Jianxun Liang ◽  
Ou Ma
Keyword(s):  
Friction Model ◽  
Contact Friction ◽  
Force Model ◽  
Tangential Plane ◽  
Stick Slip ◽  
Friction Forces ◽  
Body Contact ◽  
Point Of Interest ◽  
Experimental Effort ◽  
Sliding Regimes

This paper describes an experimental effort designed to validate a general 2D bristle contact friction model. The model extends the 1D integrated bristle friction model to a 2D space by allowing the “bristle spring” to not only stretch along the direction of the bristle displacement but also rotate due to the instantaneous direction change of the velocity or motion trend in the common tangential plane of the contacting surfaces involved at the point of interest. The model is capable of simulating frictional behaviour in both sliding and sticking regimes occurring in general 3D rigid-body contact. With such an extension, the resulting friction model can be readily used to compute 3D contact friction forces in both sticking and sliding regimes. Two experiments were designed and implemented to validate the new 2D bristle model. The experiments were able to passively produce common frictional phenomena such as sliding, sticking, and stick-slip.

Intelligent Modeling of Contact Mechanics and Friction Dynamics

2005 ◽  
Author(s):  
R. Marumo
Keyword(s):  
Contact Mechanics ◽  
Dynamic Models ◽  
Sliding Friction ◽  
Dynamic Modelling ◽  
Contact Friction ◽  
Friction Forces ◽  
Intelligent Modeling ◽  
Adhesion Contact ◽  
Frictional Forces ◽  
Friction Dynamics

This paper considers the investigations into adhesion, contact mechanics metal erosion effects, wear and tare as a result of the effects of frictional forces. Mechanical components rely on friction for the transformation and delivery of energy from point A to point B. This requires the knowledge of combined energies as well as their associated dynamic models and ancillary parameters. Adhesion, contact, friction and wear are major problems limiting both the fabrication yield and lifetime of any devices. Since it is the area of real contact, which determines the sliding friction, adhesion interaction may strongly affect the friction force even when no adhesion can be detected in a pull-off experiment. Therefore a good scientific dynamic modelling of friction forces is a prerequisite for the understanding and monitoring of friction adverse effect on mechanical systems for good maintenance purposes.

A Numerical Analysis for Piston Skirts in Mixed Lubrication—Part I: Basic Modeling

1992 ◽  
Vol 114 (3) ◽  
pp. 553-562 ◽  
Author(s):  
Dong Zhu ◽  
Herbert S. Cheng ◽  
Takayuki Arai ◽  
Kyugo Hamai
Keyword(s):  
Surface Profile ◽  
Mixed Lubrication ◽  
Contact Friction ◽  
Thermal Distortion ◽  
Surface Waviness ◽  
Piston Motion ◽  
Friction Forces ◽  
Crack Angle ◽  
Piston Skirts ◽  
Cylinder Bore

This paper presents a mathematical model for piston skirts in mixed lubrication. It takes into account the effects of surface waviness, roughness, piston skirt surface profile, bulk elastic deformation and thermal distortion of both piston skirts and cylinder bore on piston motion, lubrication and friction. The corresponding computer program developed can be used to calculate the entire piston trajectory and the hydrodynamic and contact friction forces as functions of crack angle under engine running conditions. This paper is the first part of a series of two papers. It gives basic information and some preliminary results. The second part will include the major results and discussions, focused on the influences of elastic and thermal deformations.

scholarly journals Briquetting of structurally inhomogeneous porous materials

2020 ◽  
Vol 65 (2) ◽  
pp. 205-214
Author(s):  
O. M. Dyakonov
Keyword(s):  
Porous Body ◽  
Pressure Coefficient ◽  
Energy Condition ◽  
Contact Friction ◽  
Equilibrium Equations ◽  
Friction Forces ◽  
Pressing Process ◽  
Deformation Work ◽  
Pressure Stress ◽  
Force Calculation

The work is devoted to solving the axisymmetric problem of the theory of pressing porous bodies with practical application in the form of force calculation of metallurgical processes of briquetting small fractional bulk materials: powder, chip, granulated and other metalworking wastes. For such materials, the shape of the particles (structural elements) is not geometrically correct or generally definable. This was the basis for the decision to be based on the continual model of a porous body. As a result of bringing this model to a two-dimensional spatial model, a closed analytical solution was obtained by the method of jointly solving differential equilibrium equations and the Guber–Mises energy condition of plasticity. The following assumptions were adopted as working hypotheses: the normal radial stress is equal to the tangential one, the lateral pressure coefficient is equal to the relative density of the compact. Due to the fact that the problem is solved in a general form and in a general formulation, the solution itself should be considered as methodological for any axisymmetric loading scheme. The transcendental equations of the deformation compaction of a porous body are obtained both for an ideal pressing process and taking into account contact friction forces. As a result of the development of a method for solving these equations, the formulas for calculating the local characteristics of the stressed state of the pressing, as well as the integral parameters of the pressing process are derived: pressure, stress, and deformation work.

scholarly journals Force calculation of the process of briquetting powder, chip and other bulk materials

2019 ◽  
pp. 118-125
Author(s):  
O. M. Dyakonov
Keyword(s):  
Porous Body ◽  
Pressure Coefficient ◽  
Energy Condition ◽  
Contact Friction ◽  
Equilibrium Equations ◽  
Bulk Materials ◽  
Friction Forces ◽  
Pressing Process ◽  
Deformation Work ◽  
Force Calculation

The work is devoted to solving the axisymmetric problem of the theory of pressing porous bodies with practical application in the form of force calculation of metallurgical processes of briquetting small fractional bulk materials: powder, chip, granulated and other metalworking wastes. For such materials, the shape of the particles (structural elements) is not geometrically correct or generally definable. This was the basis for the decision to be based on the continual model of a porous body. As a result of bringing this model to a two-dimensional spatial model, a closed analytical solution was obtained by the method of jointly solving differential equilibrium equations and the Guber-Mises energy condition of plasticity. The following assumptions were adopted as working hypotheses: the radial shear stress is equal to the tangential one, the lateral pressure coefficient is equal to the relative density of the compact. Due to the fact that the problem is solved in a general form and in a general formulation, the solution itself should be considered as methodological for any axisymmetric loading scheme. The transcendental equations of the deformation compaction of a porous body are obtained both for an ideal pressing process and taking into account contact friction forces. As a result of the development of a method for solving these equations, the formulas for calculating the local characteristics of the stressed state of the pressing, as well as the integral parameters of the pressing process are derived: pressure, stress, and deformation work.

Research of Combined Process “Rolling-Pressing” Influence on the Microstructure and Mechanical Properties of Aluminium

2013 ◽  
Vol 814 ◽  
pp. 68-75 ◽  
Author(s):  
Sergey Lezhnev ◽  
Evgeniy Panin ◽  
Irina Volokitina
Keyword(s):  
Mechanical Properties ◽  
Rolling Force ◽  
Raw Material ◽  
Grain Structure ◽  
Contact Friction ◽  
Empirical Formulas ◽  
Combined Process ◽  
Plastic Properties ◽  
Friction Forces ◽  
Microstructure And Mechanical Properties

In the development of new technology forming the ultimate goal is increasing of productivity, expansion of range, creating a compact production, capable of rapid reconfiguration for mobile release of the new product. But the main purpose, of course, is improvement the quality of the source material. When used as a raw material of various grades of steel, non-ferrous metals and their alloys, the main aspect of quality improvement is increasing the strength characteristics. Often to increase the strength of deformable metal should be given reduced grain structure, up to subultra and even nano-level. There are several ways to obtain sub-ultra-fine-grain structure of metals and alloys, and one of those ways is a method of severe plastic deformation of the metal, implemented in the whole volume of the deformable metal.On the department "Plastic Metal Working" of Karaganda State Industrial University was previously developed and proposed a new method of combined rolling and pressing in equal-channel step die, which compared to conventional compression in the traditional equal-channel step die ensures the continuity of the process and removes the restrictions on the size of the original pieces. The essence of the method is that workpiece which is pre-heated to a temperature of the beginning of deformation is applied to the forming rolls, which due to contact friction forces captured it in roll gap and pushed through the channels of equal- channel step die. At the exit from the die installed a second pair of rolls, which pulls the workpiece from the die.In the research of the process were made theoretical studies, after which were received the empirical formulas to determine the rolling force in the rolls and pressing force in the matrix. Also were obtained formulas for the kinematic state of the process.Also conducted a simulation of the process in the software package Deform-3D, in which produced the picture of stress - strain state and analyzed the resulting force.In this work, laboratory studies were performed of the combined process. In particular, a laboratory experiment was conducted to implement the combined process of "rolling-compaction", whose main purpose was to research the effect of the scheme on the deformation changes in the microstructure and mechanical properties of the original pieces, made of aluminum alloy AK6.Research of the mechanical properties and microstructure of deformed aluminum billet by this way was found that the implementation of the combined process of "rolling-compression" increases strength properties of aluminum, and reduced plastic properties, and the original grain during deformation is reduced.

scholarly journals PROSPECTS FOR USE OF THE RESERVE FORCES OF FRICTION ON CONTACT SURFACE IN DEFORMATION ZONE AT ROLLING TO INCREASE PROCESS EFFICIENCY

2019 ◽  
Vol 62 (10) ◽  
pp. 810-815
Author(s):  
A. R. Fastykovskii ◽  
V. I. Bazaikin ◽  
V. V. Evstifeev
Keyword(s):  
Steady State ◽  
Contact Surface ◽  
Deformation Zone ◽  
Rolling Process ◽  
Maximum Efficiency ◽  
Contact Friction ◽  
Efficiency Ratio ◽  
Friction Forces ◽  
State Process ◽  
Steady State Process

Rolling process is carried out due to power supplied to the center  of deformation using contact friction forces. Rolling takes place in two  stages  – the capture stage and the steady-state process. The capture  stage determines possibility of deformation in rolls. During this period,  retracting forces of friction are used with maximum efficiency. The  main stage of rolling is the steady-state stage of the process, where  contact friction capabilities are not fully used and reserve of friction  forces is created, which can increase efficiency of rolling process. To  balance excessive friction forces on contact surface in deformation  zone during the steady-state process, zones of advance and adhesion  appear. Their length characterize amount of excessive friction forces.  Theoretical dependences for determining slip and adhesion zones are  given taking into account variety of rolling factors. Estimation indicator of abilities of friction forces reserve at the steady-state stage is  offered as well as dependence for its definition. It is analytically established that in steady-state stage of rolling on smooth rolls with ratio    α/μз  =  1 it is possible to supply 1.7  –  2  times greater energy due to  exis ting reserve of friction force than at the stage of capture at a lower  ratio α/μз ; these numbers are even higher for rolling on grooved rolls.  Dependence which determines amount of additional power provided  by friction forces reserve is given. Promising directions of using friction forces reserve at the steady- state stage of rolling are provided to  improve its efficiency. On the example of rolling in drive – non-drive  stand, an increase in efficiency (Efficiency Ratio) of the main line of  rolling mill is established with more efficient use of friction forces  at the steady-state stage of rolling process. Theoretical dependences are given to determine Efficiency Ratio at usual rolling process and at  more full use of friction forces reserve.

scholarly journals Investigation of the influence of contact friction forces in tests on the strength of compressing wall materials

2017 ◽  
Vol 132 ◽  
pp. 03002 ◽  
Author(s):  
Nataliya Lukinova ◽  
Audrey Matrosov ◽  
Irina Serebryanaya ◽  
Yuliya Terekhina ◽  
Dariya Nizhnik
Keyword(s):  
Contact Friction ◽  
Friction Forces ◽  
Wall Materials
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