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
Author(s):  
Yang Luo ◽  
Natalie Baddour ◽  
Ming Liang

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.


Author(s):  
Steven Fillmore ◽  
Jianxun Liang ◽  
Ou Ma

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.


Author(s):  
R. Marumo

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.


1992 ◽  
Vol 114 (3) ◽  
pp. 553-562 ◽  
Author(s):  
Dong Zhu ◽  
Herbert S. Cheng ◽  
Takayuki Arai ◽  
Kyugo Hamai

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.


Author(s):  
O. M. Dyakonov

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.


Author(s):  
O. M. Dyakonov

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.


2013 ◽  
Vol 814 ◽  
pp. 68-75 ◽  
Author(s):  
Sergey Lezhnev ◽  
Evgeniy Panin ◽  
Irina Volokitina

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.


2017 ◽  
Vol 132 ◽  
pp. 03002 ◽  
Author(s):  
Nataliya Lukinova ◽  
Audrey Matrosov ◽  
Irina Serebryanaya ◽  
Yuliya Terekhina ◽  
Dariya Nizhnik

2021 ◽  
Vol 20 (1) ◽  
pp. 16-25
Author(s):  
A. A. Lukashevich ◽  
N. K. Lukashevich ◽  
N. V. Ostrovskaya

Problems with unilateral constraints are not uncommon in the practice of calculating  building construction and structures. Certain difficulties in solving them arise during contact friction, as well as the dynamic action of the load. It is known that such problems from a mathematical point of view s are not correct enough, their solution becomes more complicated and depends on the history of loading and deformation of the structure. At the same time, the ability to take into account the complex working conditions of the structure makes its calculation more complete and accurate. The paper considers the solution of  a dynamic contact problem on the basis of the finite element method and the step-by-step loading method. Unilateral constraints with Coulomb friction are modeled using contact finite elements of a frame-rod type. The method of compensating loads is applied in order to comply with the limitations under ultimate friction-sliding conditions. Based on the considered discrete contact model and the step-by-step analysis method, a numerical algorithm has been developed, which allows in one step-by-step process to integrate simultaneously the equations of motion and implement contact conditions with Coulomb friction. With the help of the proposed approach, numerical solutions of the problem pertaining to a structure contact with the base have been obtained and analyzed at various parameters of dynamic load. Comparison of the results with the solution obtained by the well-known iteration method on the ultimate friction forces allows to conclude about the efficiency and reliability of the developed algorithm under complex contact conditions and dynamic loading.


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