scholarly journals Ultrasonic stabilization technology of geometrical parameters of elastic plates

2017 ◽  
Vol 2 (2) ◽  
pp. 14-18
Author(s):  
Андрей Балаев ◽  
Andrey Balaev ◽  
Альберт Королев ◽  
Albert Korolev ◽  
Тимур Балтаев ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Pressure Sensors ◽  
Experimental Investigations ◽  
Geometrical Parameters ◽  
Elastic Plates ◽  
High Productivity ◽  
Technological Factors ◽  
Ultrasonic Oscillations ◽  
Ultrasonic Technology ◽  
Processing Modes

The paper reports the substantiation of the stabilization technology for geometrical parameters of elastic plates in pressure sensors carried out by means of residual stresses affected by ultrasonic oscillations. For the confirmation of the efficiency of the developed ultrasonic stabilization technology in accordance with the procedure described the experimental investigations are carried out. The results of the experimental study are presented by the equation of regression and diagrams of residual stresses dependences upon technological factors. Amplitudes of ultrasonic oscillations, a static force of tool pressure and machining duration were assumed as variable technological factors. High productivity and efficiency of the ultrasonic technology for elastic plate stabilization are proved experimentally. As a result of the experiment there are defined rational values of ultrasonic processing modes for specific geometrical and physical-mechanical parameters of a plate.

scholarly journals Influence of High-Productivity Process Parameters on the Surface Quality and Residual Stress State of AISI 316L Components Produced by Directed Energy Deposition

2021 ◽  
Author(s):  
Gabriele Piscopo ◽  
Alessandro Salmi ◽  
Eleonora Atzeni
Keyword(s):  
Surface Roughness ◽  
Residual Stresses ◽  
Surface Quality ◽  
Process Parameters ◽  
Energy Deposition ◽  
Industrial Applications ◽  
High Productivity ◽  
Directed Energy Deposition ◽  
Productivity Process ◽  
Directed Energy

AbstractThe production of large components is one of the most powerful applications of laser powder-directed energy deposition (LP-DED) processes. High productivity could be achieved, when focusing on industrial applications, by selecting the proper process parameters. However, it is of crucial importance to understand the strategies that are necessary to increase productivity while maintaining the overall part quality and minimizing the need for post-processing. In this paper, an analysis of the dimensional deviations, surface roughness and subsurface residual stresses of samples produced by LP-DED is described as a function of the applied energy input. The aim of this work is to analyze the effects of high-productivity process parameters on the surface quality and the mechanical characteristics of the samples. The obtained results show that the analyzed process parameters affect the dimensional deviations and the residual stresses, but have a very little influence on surface roughness, which is instead dominated by the presence of unmelted particles.

Failure Mechanisms of Particulate Two-Phase Composites

1998 ◽  
Vol 529 ◽  
Author(s):  
T. Antretter ◽  
E D. Fischer
Keyword(s):  
Residual Stresses ◽  
Crack Growth ◽  
Opening Angle ◽  
Geometrical Parameters ◽  
Two Phase ◽  
Absolute Size ◽  
The Matrix ◽  
Unit Cells ◽  
Angle Criterion ◽  
Probability Of Fracture

AbstractIn many composites consisting of hard and brittle inclusions embedded in a ductile matrix failure can be attributed to particle cleavage followed by ductile crack growth in the matrix. Both mechanisms are significantly sensitive towards the presence of residual stresses.On the one hand particle failure depends on the stress distribution inside the inclusion, which, in turn, is a function of various geometrical parameters such as the aspect ratio and the position relative to adjacent particles as well as the external load. On the other hand it has been observed that the absolute size of each particle plays a role as well and will, therefore, be taken into account in this work by means of the Weibull theory. Unit cells containing a number of quasi-randomly oriented elliptical inclusions serve as the basis for the finite element calculations. The numerical results are then correlated to the geometrical parameters defining the inclusions. The probability of fracture has been evaluated for a large number of inclusions and plotted versus the particle size. The parameters of the fitting curves to the resulting data points depend on the choice of the Weibull parameters.A crack tip opening angle criterion (CTOA) is used to describe crack growth in the matrix emanating from a broken particle. It turns out that the crack resistance of the matrix largely depends on the distance from an adjacent particle. Residual stresses due to quenching of the material tend to reduce the risk of particle cleavage but promote crack propagation in the matrix.

Experimental Inverstigations On the Pressure Fluctuations in the Sealing Gap of Dry Gas Seals with Embedded Pressure Sensors

2021 ◽  
Author(s):  
Jingjing Luo ◽  
Dieter Brillert
Keyword(s):  
High Speed ◽  
Gas Flow ◽  
Static Pressure ◽  
Pressure Sensors ◽  
Operating Conditions ◽  
Test Facility ◽  
Experimental Investigations ◽  
Mechanical Seals ◽  
Process Gas ◽  
Sealing Gap

Abstract Dry gas lubricated non-contacting mechanical seals (DGS), most commonly found in centrifugal compressors, prevent the process gas flow into the atmosphere. Especially when high speed is combined with high pressure, DGS is the preferred choice over other sealing alternatives. In order to investigate the flow field in the sealing gap and to facilitate the numerical prediction of the seal performance, a dedicated test facility is developed to carry out the measurement of key parameters in the gas film. Gas in the sealing film varies according to the seal inlet pressure, and the thickness of gas film depends on this fluctuated pressure. In this paper, the test facility, measurement methods and the first results of static pressure measurements in the sealing gap of the DGS obtained in the described test facility are presented. An industry DGS with three-dimensional grooves on the surface of the rotating ring, where experimental investigations take place, is used. The static pressure in the gas film is measured, up to 20 bar and 8,100 rpm, by several high frequency ultraminiature pressure transducers embedded into the stationary ring. The experimental results are discussed and compared with the numerical model programmed in MATLAB, the characteristic and magnitude of which have a good agreement with the numerical simulations. It suggests the feasibility of measuring pressure profiles of the standard industry DGS under pressurized dynamic operating conditions without altering the key components of the seal and thereby affecting the seal performance.

On the Extraction of Milling Tools Out of Shrink Fit Chucks

2012 ◽  
Vol 523-524 ◽  
pp. 445-450 ◽  
Author(s):  
Berend Denkena ◽  
Dennis Heinisch
Keyword(s):  
High Performance ◽  
Experimental Investigations ◽  
Process Conditions ◽  
Geometrical Parameters ◽  
Dynamic Force ◽  
Unique Type ◽  
Milling Operations ◽  
Torque Transmission ◽  
Shrink Fit ◽  
Milling Tools

Thermal shrink fit chucks are widely used in high performance machining where excellent concentricity and high torque transmission are required. It was reported that in those milling operations, severe damage of tools, workpieces, and also machine tools occurs due to an extraction of the milling tool out of the shrink fit chuck during the process. Although, theoretically the interference fit assembly should withstand certain process forces, milling tools are apparently pulled out under special process conditions. The resulting increase of the cutting depth often leads to tool overload and breakage. So far, the phenomenon of tool extraction could not be explained. This paper presents an experimental approach of the investigation of the phenomenon of axial tool extraction. Therefore, a unique type of test rig for main spindles and tool interfaces is used. Experimental investigations on dynamic force and torque combinations leading to tool extraction are described. Results show, that the holding force is not only affected by geometrical parameters of the shrink fit chuck, but also by the applied dynamic load.

Numerical and Experimental Investigations on the Residual Stresses at the Centre of Flat Glass Disks After Thermal Tempering

2008 ◽  
Vol 39-40 ◽  
pp. 553-558 ◽  
Author(s):  
Frédéric Soulié ◽  
Norbert Siedow ◽  
John Anton ◽  
Dominique Lochegnies
Keyword(s):  
Residual Stresses ◽  
Scattered Light ◽  
Flat Glass ◽  
Experimental Investigations ◽  
Stress Profile ◽  
Air Cooling ◽  
Conductive Heat ◽  
Air Jets ◽  
Complete Procedure ◽  
Disk Centre

Flat glass disks are thermally tempered by air-cooling with two air jets at the centre of their surfaces. Numerical modelling and photoelasticity measurements are proposed to analyze the distribution of the residual stresses through the glass thickness at the centre of the tempered disks. For the modelling, glass properties dependent of the temperature are used for the conductive heat transfer. Radiation is modelled by an improved approximation method. By taking both structural and stress relaxations into account, the transient and residual stresses are computed along the disk thickness. For experimentation, a complete procedure is proposed to access to the stress state in the centre of the disks using a scattered light polariscope. The average distribution of the residual stresses is deduced from stress profile measurements taking four radial orientations at the disk centre into consideration. Comparison between numerical and experimental values is finally discussed for the residual surface and half-thickness stresses at the disk centre.

Influence of coupled fields on free vibration and static behavior of functionally graded magneto-electro-thermo-elastic plate

2017 ◽  
Vol 29 (7) ◽  
pp. 1430-1455 ◽  
Author(s):  
Vinyas Mahesh ◽  
Piyush J Sagar ◽  
Subhaschandra Kattimani
Keyword(s):  
Finite Element ◽  
Electric Fields ◽  
Elastic Plate ◽  
Coupling Effect ◽  
Shear Deformation Theory ◽  
Functionally Graded ◽  
Finite Element Formulation ◽  
Geometrical Parameters ◽  
Element Formulation ◽  
Elastic Plates

In this article, the influence of full coupling between thermal, elastic, magnetic, and electric fields on the natural frequency of functionally graded magneto-electro-thermo-elastic plates has been investigated using finite element methods. The contribution of overall coupling effect as well as individual elastic, piezoelectric, piezomagnetic, and thermal phases toward the stiffness of magneto-electro-thermo-elastic plates is evaluated. A finite element formulation is derived using Hamilton’s principle and coupled constitutive equations of magneto-electro-thermo-elastic material. Based on the first-order shear deformation theory, kinematics relations are established and the corresponding finite element model is developed. Furthermore, the static studies of magneto-electro-elastic plate have been carried out by reducing the fully coupled finite element formulation to partially coupled state. Particular attention has been paid to investigate the influence of thermal fields, electric fields, and magnetic fields on the behavior of magneto-electro-elastic plate. In addition, the effect of pyrocoupling on the magneto-electro-elastic plate has also been studied. Furthermore, the effect of geometrical parameters such as aspect ratio, length-to-thickness ratio, stacking sequence, and boundary conditions is studied in detail. The investigation may contribute significantly in enhancing the performance and applicability of functionally graded magneto-electro-thermo-elastic structures in the field of sensors and actuators.

scholarly journals Rotating Stall in Centrifugal Compressor Vaneless Diffuser: Experimental Analysis of Geometrical Parameters Influence on Phenomenon Evolution

2004 ◽  
Vol 10 (6) ◽  
pp. 433-442 ◽  
Author(s):  
Giovanni Ferrara ◽  
Lorenzo Ferrari ◽  
Leonardo Baldassarre
Keyword(s):  
Centrifugal Compressor ◽  
Dynamic Pressure ◽  
Pressure Sensors ◽  
Experimental Tests ◽  
Fast Response ◽  
Rotating Stall ◽  
Geometrical Parameters ◽  
Vaneless Diffuser ◽  
Response Dynamic ◽  
Frequency Domains

The rotating stall is a key problem for achieving a good working range of a centrifugal compressor and a detailed understanding of the phenomenon is very important to anticipate and avoid it. Many experimental tests have been planned by the authors to investigate the influence on stall behavior of different geometrical configurations. A stage with a backward channel upstream, a 2-D impeller with a vaneless diffuser and a constant cross-section volute downstream, constitute the basic configuration. Several diffuser types with different widths, pinch shapes, and diffusion ratios were tested. The stage was instrumented with many fast response dynamic pressure sensors so as to characterize inception and evolution of the rotating stall. This kind of analysis was carried out both in time and in frequency domains. The methodology used and the results on phenomenon evolution will be presented and discussed in this article.

Residual Stress Formation at Arbitrary Types of Rollers during the Running in Process

2012 ◽  
Vol 548 ◽  
pp. 372-376
Author(s):  
O.P. Muraviev ◽  
M.R. Sikhimbayev ◽  
B.N. Absadykov ◽  
B.S. Arymbekov ◽  
Y.O. Tkacheva
Keyword(s):  
Residual Stresses ◽  
Surface Deformation ◽  
Calculated Data ◽  
Sharp Decrease ◽  
The Body ◽  
Experimental Investigations ◽  
Body Parts ◽  
Adequate Treatment ◽  
Significance Level ◽  
Plastic Surface

In the article the results of the design and analysis of mathematical model for determining residual stresses in the surface of layer at parts processed by plastic surface deformation (PSD) in which the rollers having an arbitrary shape and size. It is shown that for the calculation of stresses in the surface of layer it should not be defined by them at a forcing point but by a function of contact stresses. Integral equations are obtained for calculating the stresses in the body parts at the processing of PSD rolls of arbitrary size and shape of the stress distribution over the contact area. We found that the tangential and radial residual stresses depend on the magnitude of the force F and its distance from the point at which the voltage is considered in detail. There is a sharp decrease in the influence of forces on the stress in the surface of the part of the distance to the point in question.The calculated data generated by the proposed method are highly matches with data during the experimental investigations. Maximum deviations of the calculated values do not exceed the errors of the experiments and adequate treatment of each other at a significance level of 0.05.

Relieving of Residual Stresses in Metal Workpieces at High and Low Temperatures

2021 ◽  
Vol 887 ◽  
pp. 651-656
Author(s):  
Marina V. Polonik
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Residual Stresses ◽  
Low Temperatures ◽  
Creep Properties ◽  
Processing Modes ◽  
Properties Of Materials ◽  
High And Low Temperatures ◽  
Temperature Heating ◽  
High Temperature Heating

On the basis of previously accumulated irreversible deformations, and, consequently, residual stresses, the process of removing residual stresses in metal workpieces under the action of low and high temperatures is simulated. Boundary value problems are solved and here are described regularities that are responsible for removing residual stresses for processing modes: high-temperature heating - cooling, high-temperature heating - holding - cooling, low-temperature heating - holding - cooling. The holding stage is modeled, taking into account the creep properties of materials under Norton creep conditions. According to the dependences of the obtained exact solutions, it is shown that it is the holding process that leads to the relaxation of residual stresses.

Tolerance-Based Optimization of Sinking EDM for Industrial Seal Slot Manufacture

2021 ◽  
Author(s):  
Timm Petersen ◽  
Markus Zeis ◽  
Thomas Bergs
Keyword(s):  
Electrical Discharge Machining ◽  
Experimental Investigations ◽  
Discharge Energy ◽  
Machining Performance ◽  
Wear Rates ◽  
High Productivity ◽  
Aspect Ratios ◽  
Recast Layer Thickness ◽  
Turbine Vanes ◽  
Working Principle

Abstract Seal plates for turbine vanes significantly reduce gap losses and thus play a major role in increasing the efficiency of turbines. The industrial production of seal slots, which position the seal plates in the turbine vanes, is driven by the need for high productivity in combination with a reliable processing of necessary geometrical and surface integrity features. A machining technology that is able to machine hard-to-cut materials such as nickel-based alloys is electrical discharge machining. Due to its electro-thermal working principle it is able to machine materials independently from their mechanical properties even at high aspect ratios. Achievable removal and wear rates as well as the resulting surface properties strongly depend on the discharge energy. Furthermore, the discharge energy affects the working gap sizes and therefore flushing efficiencies when machining high aspect ratio cavities. This relationship is investigated taking into account various contemporary generator technologies and graphite grades from both published literature and own experimental investigations. Their effect on machining performance focusing on productivity, recast layer thickness and crack formation is quantified. Based on this data a novel empirical model for tolerance-based optimization is developed. The model is used to perform an optimization on an existing serial production and implementation has been proven successful.

Sign in / Sign up

Export Citation Format

Share Document