scholarly journals Mechanical Properties and Their Quantification Particularly When Transiting from Elastic to Plastic State on Materials Cut by AWJ

2018 ◽  
Vol 15 (2) ◽  
pp. 52-57
Author(s):  
Marek Šafář ◽  
Marta Harničárová ◽  
Milena Kušnerová ◽  
Jan Valíček
Keyword(s):  
Surface Topography ◽  
Tool Material ◽  
Abrasive Waterjet ◽  
Plastic State ◽  
Mechanical Resistance ◽  
Stress Strain ◽  
Flexible Tool ◽  
Geometrical Properties ◽  
Material Systems ◽  
Theoretical Results

Abstract Mechanical behaviour of materials during and after cutting process is depended on various factors. Surface topography is set of factors including mechanical and geometrical properties. From the surface topography, it is possible to resolve the transition from ideally elastic to quasi-elastic and plastic stress-strain states, particularly by finding a neutral plane of cut, where the compressive and tensile components are still in equilibrium. The paper solves the problem of the nonexistence of a new method for calculation of dynamics of stress-deformation states of deformation tool-material systems including the construction of stress-strain diagrams. The presented solution focuses on explaining the mechanical behavior of materials after cutting by abrasive waterjet technology (AWJ) which is a flexible tool accurately responding to the mechanical resistance of the material according to the accurately determined shape and roughness of machined surfaces. Theoretical results were compared by a certified laboratory VUHZ.

scholarly journals Proposition of a Solution for the Setting of the Abrasive Waterjet Cutting Technology

2013 ◽  
Vol 13 (5) ◽  
pp. 279-285 ◽  
Author(s):  
J. Valíček ◽  
M. Harničárová ◽  
M. Kušnerová ◽  
R. Grznárik ◽  
J. Zavadil
Keyword(s):  
Surface Topography ◽  
Surface Condition ◽  
Tool Material ◽  
Point Of View ◽  
Abrasive Waterjet ◽  
Depth Of Cut ◽  
Technological Parameters ◽  
Final Surface ◽  
Analytical Processing ◽  
The Subject

Abstract The submitted paper aims to clarify the abrasive waterjet technology, particularly from the point of view of produced surface topography. It provides a new insight into the deformation process caused by the effect of abrasive waterjet and into the possibilities of using the surface topography for solving the issues of optimization of the process. The subject of study is a system of cutting tool, material and final surface topography and optimization of their parameters. The cutting or disintegrating tool of abrasive waterjet technology is flexible. The trajectory of its cut traces is strictly determined here by disintegration resistance at critical moments of tool-material interaction. The physico-mechanical character of the interaction within the cut will manifest itself in the final surface condition. This process can be re-analysed by measuring the selected elements of topography and roughness on the final surface, namely depending on the depth of the cut, technological parameters of the tool and mechanical parameters of the material. The mentioned principle is the basis of the presented solution. It lies in the analytical processing and description of correlation interrelations between set technological and measured topographical quantities in relation to the depth of cut and the type of material.

scholarly journals Predicting Specific Stress of Cotton Staple Ring Spun Yarns: Experimental and Theoretical Results

2017 ◽  
Vol 25 (0) ◽  
pp. 43-47 ◽  
Author(s):  
Muhammad Zubair ◽  
Bohuslav Neckář ◽  
Zilfiqar Malik
Keyword(s):  
Reasonable Agreement ◽  
Twist Angle ◽  
Strain Curve ◽  
Stress Strain Curve ◽  
Fiber Stress ◽  
Stress Strain ◽  
New Approach ◽  
Contraction Ratio ◽  
Spun Yarns ◽  
Theoretical Results

The aim of this research is to predict the yarn specific stress from fiber specific stress and fiber stress utilisation. In this paper a new approach is introduced to predict the specific stress-strain curves of cotton carded and combed yarns. The force on single fiberis worked out and these fiber forces are combined together to obtain forces acting on yarn. The theoretical model introduces the utilisation of fiber stress on the basis of the fiber specific stress-strain curve, twist angle, fiber directional distribution parameter C and contraction ratio. A comparison of experimental results suggests that the specific stress-strain curves predicted have reasonable agreement with the experimental yarn specific stress-strain curves for all types of yarns. Thus this model is valid to predict the specific stress-strain curves for carded and combed cotton ring spun yarns.

Fundamental Characteristics of a New Variable Torque Clutch With Skewed Rollers

1999 ◽  
Vol 123 (3) ◽  
pp. 436-446 ◽  
Author(s):  
Ming Feng ◽  
Kyosuke Ono ◽  
Kenji Mimura
Keyword(s):  
Design Parameters ◽  
Equilibrium Equations ◽  
Linear Distribution ◽  
Outer Race ◽  
Geometrical Properties ◽  
Torque Transmission ◽  
Nonlinear Equilibrium ◽  
Torque Capacity ◽  
New Type ◽  
Theoretical Results

In this paper, a new type of a clutch by the name of the variable torque clutch with skewed rollers is first introduced and second investigated both theoretically and experimentally. It is comprised of an inner and an outer race that are each in spatial line contact with the crossed axis cylindrical rollers. Torque transmission is delivered by a slipping induced between the rollers and the races due to skewing the rollers. The equations of the race surfaces are derived and the geometrical properties are analyzed. Based on the kinematic analysis, a roller-wedge model is proposed for this clutch in order to visualize the motion at the tangency of the rollers and the races. By assuming the linear distribution of the contact force along the spatial contact line, the transmitted torque capacity and kinematic characteristics can be evaluated properly from the solution of a set of nonlinear equilibrium equations. Several prototypes of this clutch are manufactured and measured to show the validity of this design idea and the theoretical results. The computational results are found to coincide with the experimental data. In addition, the influences of the design parameters on the fundamental characteristics are discussed in detail.

scholarly journals Compressive Behavior for Surface-Nanocrystallized Al-Alloy Material

2002 ◽  
Vol 740 ◽  
Author(s):  
Yueguang Wei ◽  
Chen Zhu ◽  
Xiaolei Wu
Keyword(s):  
Compressive Stress ◽  
Cell Model ◽  
Material Behavior ◽  
Theoretical Research ◽  
Al Alloy ◽  
Compressive Behavior ◽  
Stress Strain ◽  
Alloy Material ◽  
Ultrasonic Shot Peening ◽  
Theoretical Results

ABSTRACTMechanical behavior of the surface-nanocrystallized material fabricated by the ultrasonic shot peening method is investigated experimentally and theoretically. In the experimental research, based on microscopic observations, the compressive specimens are designed and machined considering the material features, and the compressive experiments are performed. Furthermore the compressive stress-strain curves are measured. In the theoretical research, a microstructure cell model is presented considering the material microscopic organization observed from experiments, and the compressive stress-strain relations are simulated. Both experimental and theoretical results display the strong size effect on the material behavior.

scholarly journals Surface Topography Analysis of Mg-Based Composites with Different Nanoparticle Contents Disintegrated Using Abrasive Water Jet

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5471
Author(s):  
Kumari Bimla Mardi ◽  
Amit Rai Dixit ◽  
Alokesh Pramanik ◽  
Pavol Hvizdos ◽  
Ashis Mallick ◽  
...  
Keyword(s):  
Surface Topography ◽  
Flow Rate ◽  
Water Pressure ◽  
Traverse Speed ◽  
Water Jet ◽  
Abrasive Waterjet ◽  
Maximum Height ◽  
Average Particle ◽  
Abrasive Water Jet ◽  
Metal Matrix Nanocomposites

This study investigated the effect of abrasive water jet kinematic parameters, such as jet traverse speed and water pressure, on the surface of magnesium-based metal matrix nanocomposites (Mg-MMNCs) reinforced with 50 nm (average particle size) Al2O3 particles at concentrations of 0.66 and 1.11 wt.%. The extent of grooving caused by abrasive particles and irregularities in the abrasive waterjet machined surface with respect to traverse speed (20, 40, 250 and 500 mm/min), abrasive flow rate (200 and 300 g/min) and water pressure (100 and 400 MPa) was investigated using surface topography measurements. The results helped to identify the mode of material disintegration during the process. The nanoindentation results show that material softening was decreased in nanocomposites with higher reinforcement content due to the presence of a sufficient amount of nanoparticles (1.11 wt.%), which protected the surface from damage. The values of selected surface roughness profile parameters—average roughness (Ra), maximum height of peak (Rp) and maximum depth of valleys (Rv)—reveal a comparatively smooth surface finish in composites reinforced with 1.11 wt.% at a traverse speed of 500 mm/min. Moreover, abrasive waterjet machining at high water pressure (400 MPa) produced better surface quality due to sufficient material removal and effective cleaning of debris from the machining zone as compared to a low water pressure (100 MPa), low traverse speed (5 mm/min) and low abrasive mass flow rate (200 g/min).

scholarly journals DETERMINATION OF STRESS-STRAIN STATE OF THE BODY SURFACE OR ITS AREA IN CASE OF PERFECT PLASTICITY AT GIVEN STRESS AND DISPLACEMENT VECTORS

2020 ◽  
Vol 2 ◽  
pp. 201-209
Author(s):  
Anvar I. Chanyshev ◽  
Ilgizar M. Abdulin ◽  
Olga A. Lukyashko
Keyword(s):  
Body Surface ◽  
Strain State ◽  
Rapid Assessment ◽  
Strain Tensor ◽  
The Body ◽  
Plastic State ◽  
Cauchy Stress ◽  
Stress Strain ◽  
Stress Strain State ◽  
Displacement Vectors

Ideally plastic state of material under conditions of Mises plasticity, proportionality of stress and strain deviators (deformation theory of plasticity) and elastic volume change is considered. Given the Cauchy stress and displacement vectors specified on the body surface (with indicated state) or its area, all six components of the stress tensor, all six components of the strain tensor, and also three components of the rotation vector are restored on this surface. This method for determining the stress-strain state can be related to the methods of rapid assessment of the structure state (body surface), since differential equations inside the body are not involved.

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