Experimental Study of Tangential Micro Deflection of Interface of Machined Surfaces

1999 ◽  
Vol 123 (2) ◽  
pp. 365-367 ◽  
Author(s):  
Jun Ni ◽  
Zhenqi Zhu
Keyword(s):  
Experimental Study ◽  
Plastic Deformation ◽  
Elastic Deformation ◽  
Tangential Force ◽  
Experimental Results ◽  
Contact Interface ◽  
Tangential Stiffness ◽  
Tangential Forces ◽  
Elastic And Plastic Deformation ◽  
Machined Surfaces

This paper studies the characteristics of micro tangential deflection of the interface of mating machined surfaces subjected to normal and tangential forces. Experimental results show that contact interface subjected to a tangential force experiences elastic deformation, plastic deformation and micro slip before macro-breakaway occurs. The linearity of tangential stiffness is only valid in the stage of elastic deformation. The nonlinear tangential stiffness of the interface should be considered in the stages of elastic and plastic deformation before micro-breakaway occurs.

Experimental Study of the Plastic Interaction of Model Surface Asperities during Sliding

1968 ◽  
Vol 10 (2) ◽  
pp. 121-132 ◽  
Author(s):  
C. M. Edwards ◽  
J. Halling
Keyword(s):  
Experimental Study ◽  
Friction And Wear ◽  
Normal Force ◽  
Tangential Force ◽  
Experimental Results ◽  
Interfacial Conditions ◽  
High Adhesion ◽  
Theoretical Predictions ◽  
Very High ◽  
Low Shear

The paper describes an experimental study of the plastic interaction of triangular shaped lead model asperities deformed under conditions of plane strain. The investigation yields values of the normal and tangential force variations throughout the junction interaction and details of the plastic deformation particularly in relation to junction growth. A number of asperity interfacial conditions are considered ranging from complete adhesion to very low shear strengths achieved using p.t.f.e. strip. The experimental results are compared with an earlier theoretical solution to this problem and show reasonable agreement with the theoretical predictions. In particular it is shown that the normal force, which is usually compressive, may become tensile for conditions of high adhesion between the asperities. This leads to very high values of the macroscopic friction coefficient such as occur in hard vacuum situations. The experimental results for the various surface conditions show sufficient agreement with theoretical predictions to justify the use of this type of theoretical approach for the wider study of the friction and wear of mating surfaces.

Settlement Behavior of New Reinforced Earth Retaining Walls under Loading-Unloading Cycles

2012 ◽  
Vol 256-259 ◽  
pp. 215-219
Author(s):  
Yu Liang Lin ◽  
Yi He Fang
Keyword(s):  
Plastic Deformation ◽  
Elastic Deformation ◽  
Retaining Wall ◽  
Retaining Walls ◽  
Secant Modulus ◽  
Loading Level ◽  
Settlement Behavior ◽  
Reinforced Earth ◽  
Earth Structures ◽  
Elastic And Plastic Deformation

Three new types of reinforced earth structures were introduced including reinforced gabion retaining wall, green reinforced gabion retaining wall and flexible wall face geogrid reinforced earth retaining wall. In order to study settlement behavior of these three retaining walls, lab tests were carried out. Cyclic loading-unloading of different levels (0~50kPa, 0~100kPa, 0~150kPa, 0~200kPa, 0~250kPa, 0~300kPa, 0~350kPa) were imposed. The settlement behaviors of retaining walls were analyzed, and secant modulus when loading and unloading was obtained. Results show that retaining walls present great elastic and plastic deformation, and plastic deformation is greater than elastic deformation. Secant modulus decreases with the increase of loading-unloading cycles under the same loading level. Unloading secant modulus is bigger than loading secant modulus in the same cycle. With the increase of loading level, both elastic and plastic deformation increase, and plastic deformation increases more quickly than elastic deformation.

Experimental Study on the Wet Molding for Wheat Straw Pellet Fuel

2010 ◽  
Vol 156-157 ◽  
pp. 284-292 ◽  
Author(s):  
Jian Jun Hu ◽  
Quan Guo Zhang ◽  
Ting Zhou Lei ◽  
Zhi Wei Wang
Keyword(s):  
Mathematical Model ◽  
Experimental Study ◽  
Plastic Deformation ◽  
Linear Equation ◽  
Wheat Straw ◽  
Elastic Deformation ◽  
Moisture Ratio ◽  
Transitional Stage ◽  
Exponential Equation ◽  
The Impact

In the paper, in order to investigate the situation of impact on wet molding for straw of compressing speed and moisture ratio, and look for the inside law between them, closed compress experimental study on the wet molding for wheat straw pellet fuel was done by electrical universal material experimental machine and experimental provision made by oneself. Study on the impact situation for compressing speed and moisture ratio was done from pressure intensity, displacement and density of materiel. The result, which low compressing speed and low moisture ratio were propitious to wet molding, was gotten. The molding stage can be divided to loose stag, transitional stage, compressing stage. Partial elastic deformation mainly occurred In loose stage, and its mathematical model was linear equation. Elastic deformation mainly occurred In transitional stage, and its mathematical model was exponential equation. Plastic deformation mainly occurred In compressing stage, and its mathematical model was linear equation. The conclusion above has general directive significance to wet molding for straw pellet fuel.

Experimental Study and Mathematical Modeling of Development of Crystallographic Slip in Heterophase FCC Alloys

2014 ◽  
Vol 1013 ◽  
pp. 300-306
Author(s):  
Nina Grigorjeva ◽  
Olga Daneyko ◽  
Tatiana Kovalevskaya
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Experimental Study ◽  
Plastic Deformation ◽  
Experimental Results ◽  
Plastic Behavior ◽  
Crystallographic Slip ◽  
Fcc Alloys ◽  
Fcc Materials ◽  
The Mathematical Model

The experimental results of plastic behavior investigation of Al-6%Zn-3%Mg alloy are compared with the mathematical model of plastic deformation of dispersion hardened FCC materials with undeformed particles. Were determined the factors, when model properly describes the regularities of slip development in this alloy.

Running Force in Medium to High-Curvature Wellbores: An Experimental Study and Numerical Simulation of Laboratory and Field Cases

2000 ◽  
Vol 123 (2) ◽  
pp. 133-137
Author(s):  
Abdennour C. Seibi
Keyword(s):  
Numerical Simulation ◽  
Experimental Study ◽  
Plastic Deformation ◽  
Element Model ◽  
Field Conditions ◽  
Radius Of Curvature ◽  
Horizontal Section ◽  
Novel Approach ◽  
Simulated Field ◽  
Elastic And Plastic Deformation

This paper presents a novel approach to measure and estimate running force for various laboratory and field conditions. The experimental and simulation procedures of different rod/pipe sizes running through various laboratory/field conditions are described in detail. Tests were conducted on rods to measure the running force for various laboratory cases obtained from dimensional analysis. The generated experimental results were used to calibrate a typical laboratory finite element model from which calibrated parameters are used to estimate the running force for prescribed field cases. Both the experimental and simulated field results revealed that the running force depends on the radius of curvature, hole clearance, horizontal section, and contact scenario significantly. Stress analysis of pipes running through curved and horizontal sections showed that pipes undergo elastic and plastic deformation, and the nature of deformation depends on the pipe size and radius of curvature.

Emergence of tangential stiffness through the use of inclined orthotropic material

2020 ◽  
pp. 095440622096796
Author(s):  
Tadayoshi Shoyama ◽  
Yutaka Wada ◽  
Osami Matsushita
Keyword(s):  
Orthotropic Material ◽  
Tangential Force ◽  
Reaction Force ◽  
Tangential Stiffness ◽  
Oil Whirl ◽  
Excited Vibration ◽  
Rotationally Symmetric ◽  
Tangential Forces ◽  
Degree Of Anisotropy ◽  
Stabilization Effect

A flexible bearing support structure is effective for stabilizing the self-excited vibration of a bearing, such as oil whirl. The stabilization effect is increased if the structure has static tangential stiffness, where the reaction force is perpendicular to the displacement. In this study, it is shown that a support component made of inclined orthotropic material, which exhibits shear–extension coupling, can have tangential stiffness.　The circumferential average of the tangential stiffness was found to vanish with a rotationally symmetric configuration of these components because the tangential forces of each component cancel out. However, the tangential force was recovered by allowing separation on the contact surface. A circular formation of an inclined orthotropic sheet that shows an axisymmetric stiffness matrix is proposed. Theoretical and numerical analyses clarified the effects of the friction coefficient, fitting interference, and degree of anisotropy of the material. Zero interference was found to be the best condition to maximize tangential stiffness.

Friction Force and Stresses Analysis for Contact of Assembled Details

2006 ◽  
Vol 113 ◽  
pp. 334-338
Author(s):  
Z. Dreija ◽  
O. Liniņš ◽  
Fr. Sudnieks ◽  
N. Mozga
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Plastic Deformation ◽  
Friction Force ◽  
Sliding Friction ◽  
Friction Model ◽  
Contact Interface ◽  
Finite Element Program ◽  
Elastic Plastic ◽  
Element Program

The present work deals with the computation of surface stresses and deformation in the presence of friction. The evaluation of the elastic-plastic contact is analyzed revealing three distinct stages that range from fully elastic through elastic-plastic to fully plastic contact interface. Several factors of sliding friction model are discussed: surface roughness, mechanical properties and contact load and areas that have strong effect on the friction force. The critical interference that marks the transition from elastic to elastic- plastic and plastic deformation is found out and its connection with plasticity index. A finite element program for determination contact analysis of the assembled details and due to details of deformation that arose a normal and tangencial stress is used.

scholarly journals Micromechanism of the Breakage of Two Spherical Gypsum Particles under Normal–Tangential Contact Conditions

2021 ◽  
Vol 11 (9) ◽  
pp. 4039
Author(s):  
Yiran Niu ◽  
Lin Li ◽  
Yanwei Zhang ◽  
Shicai Yu ◽  
Jian Zhou
Keyword(s):  
Tangential Force ◽  
Coarse Grained ◽  
Spherical Particles ◽  
Contact Conditions ◽  
Normal Contact ◽  
Tangential Contact ◽  
Theoretical Predictions ◽  
Tangential Forces ◽  
Predicted Values ◽  
The Relationship

Contact breakage of particles makes a large difference in the strength of coarse-grained soils, and exploring the characteristics within the process of the breakage is of great significance. Ignoring the influence of particle shape, the micromechanism of two spherical particles breaking under normal–tangential contact conditions was investigated theoretically and experimentally. Through theoretical analysis, the breakage form, the shape and size of the conical core, and the relationship between the normal and tangential forces at crushing were predicted. Particle contact tests of two gypsum spheres were carried out, in which the breakage forms, features of the conical cores and the normal and tangential forces at crushing were recorded for comparison with the predicted values. The test results and the theoretical predictions showed good agreement. Both the analysis and test demonstrate that the presence of tangential forces causes the conical core to assume the shape of an oblique cone, and the breakage form to change. Moreover, with increasing normal contact force, the tangential force needed for crushing increases gradually first and then decreases suddenly.

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