scholarly journals Achievement of required surface roughnesses in complex profile channels by dynamic combined processing

2018 ◽  
Vol 226 ◽  
pp. 01021
Author(s):  
Alexander I. Boldyrev ◽  
Gennady A. Sukhochev ◽  
Alexander A. Boldyrev ◽  
Denis V. Silaev ◽  
Vasily N. Sokolnikov
Keyword(s):  
Anodic Dissolution ◽  
Low Voltage ◽  
Cold Work ◽  
Surface Profile ◽  
Field Research ◽  
Operating Conditions ◽  
Mechanical Processing ◽  
Mechanical Parameters ◽  
Processing Conditions ◽  
Complex Profile

At present for processing of complex geometrical channels of workpieces electrochemical dimensional processing, vibro-impact machining and vibro-extruding are widely used. However combined electrochemical mechanical processing, that unites anodic dissolution and plastic flow of material in space and time, provides the required characteristics of surface layer. Local action anodic dissolution changes cold work amount and accelerates dissolution of micro- and macro-cusps, this causes annealing of physical and mechanical parameters in processed segments and accross the whole surface profile the required strengthening degree is attained. The authors examine annealing model for microsurface by grain displacement in channel where extrusion forcing is dictated by grains size and profile of narrow blade channel and also by actual processing conditions. Operating conditions that are recommended for implementation of combined electrochemical mechanical processing of impeller and turbine type workpieces are found by experiments. In consequence of field research they determined availability of standard microgeometry across the whole surface profile by combined processing with vibrations hashing with up to 2030 Hz frequency and low voltage current (in operation range from 1,2 till 1,8 V). Therein technological cycle decreases up to two fold, this reduces inadmissible jumping of blade edges and dimensional allowance.

scholarly journals Strengthening of materials by vibroimpact and combined methods with previous electrochemical processing

2018 ◽  
Vol 224 ◽  
pp. 01097 ◽  
Author(s):  
Alexander I. Boldyrev ◽  
Alexander A. Boldyrev ◽  
Oleg N. Fedonin
Keyword(s):  
Anodic Dissolution ◽  
Cold Work ◽  
High Accuracy ◽  
Experimental Investigations ◽  
Mechanical Processing ◽  
Technological Capabilities ◽  
Electrochemical Processing ◽  
Evaluation Test ◽  
Ultimate Resistance ◽  
Combined Methods

The authors examine capabilities of vibroimpact strengthening after electrochemical processing of materials, also getting guaranteed cold work of the surface during simultaneous anodic dissolution and mechanic calibration. They propose the technique of electrochemical mechanical processing. This article contains the results of experimental investigations. This technique passed evaluation test during production of shell cases with high accuracy and guaranteed hole cold work. The received results give ground for affirmation that electrochemical processing that proceeds hardening enables great extension of technological capabilities of this method and successful continuation investigations directed at creation of lighter constructions with higher ultimate resistance at reversed loads.

Influence of Thermo-Mechanical Processing on the Microstructure of Beryllia Dispersed Nickel Alloys

1973 ◽  
Vol 31 ◽  
pp. 184-185
Author(s):  
M.S. Grewal ◽  
S.A. Sastri ◽  
N.J. Grant
Keyword(s):  
High Temperature ◽  
Nickel Alloys ◽  
Thermomechanical Processing ◽  
Cold Work ◽  
High Temperature Strength ◽  
Strengthening Effect ◽  
Mechanical Processing ◽  
Uniform Dispersion ◽  
Oxide Particles ◽  
Nickel Base

Currently there is a great interest in developing nickel base alloys with fine and uniform dispersion of stable oxide particles, for high temperature applications. It is well known that the high temperature strength and stability of an oxide dispersed alloy can be greatly improved by appropriate thermomechanical processing, but the mechanism of this strengthening effect is not well understood. This investigation was undertaken to study the dislocation substructures formed in beryllia dispersed nickel alloys as a function of cold work both with and without intermediate anneals. Two alloys, one Ni-lv/oBeo and other Ni-4.5Mo-30Co-2v/oBeo were investigated. The influence of the substructures produced by Thermo-Mechanical Processing (TMP) on the high temperature creep properties of these alloys was also evaluated.

scholarly journals A Novel Hybrid LDC Converter Topology for the Integrated On-Board Charger of Electric Vehicles

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3603
Author(s):  
Vu-Hai Nam ◽  
Duong-Van Tinh ◽  
Woojin Choi
Keyword(s):  
Low Voltage ◽  
Operating Conditions ◽  
Maximum Efficiency ◽  
Battery Charger ◽  
Forward Converter ◽  
Vehicle To Grid ◽  
Circulating Current ◽  
In Series ◽  
Converter Topology ◽  
Output Capacitor

Recently, the integrated On-Board Charger (OBC) combining an OBC converter with a Low-Voltage DC/DC Converter (LDC) has been considered to reduce the size, weight and cost of DC-DC converters in the EV system. This paper proposes a new integrated OBC converter with V2G (Vehicle-to-Grid) and auxiliary battery charge functions. In the proposed integrated OBC converter, the OBC converter is composed of a bidirectional full-bridge converter with an active clamp circuit and a hybrid LDC converter with a Phase-Shift Full-Bridge (PSFB) converter and a forward converter. ZVS for all primary switches and nearly ZCS for the lagging switches can be achieved for all the operating conditions. In the secondary side of the proposed LDC converter, an additional circuit composed of a capacitor and two diodes is employed to clamp the oscillation voltage across rectifier diodes and to eliminate the circulating current. Since the output capacitor of the forward converter is connected in series with the output capacitor of the auxiliary battery charger, the energy from the propulsion battery can be delivered to the auxiliary battery during the freewheeling interval and it helps reduce the current ripple of the output inductor, leading to a smaller volume of the output inductor. A 1 kW prototype converter is implemented to verify the performance of the proposed topology. The maximum efficiency of the proposed converter achieved by the experiments is 96%.

Ball Grid Array Thermomechanical Response During Reflow Assembly

1996 ◽  
Vol 118 (4) ◽  
pp. 214-222 ◽  
Author(s):  
T. E. Voth ◽  
T. L. Bergman
Keyword(s):  
Process Model ◽  
Experimental Studies ◽  
Ball Grid Array ◽  
Mechanical Processing ◽  
Processing Conditions ◽  
System Behavior ◽  
Reflow Soldering ◽  
Thermomechanical Response ◽  
Model Predictions ◽  
Representative System

The thermomechanical response of ball-grid array assemblies during reflow soldering is considered here. Experiments are performed to investigate the thermomechanical response of a representative system and the results are used to validate a numerical model of system behavior. The conclusions drawn from the experimental studies are used to guide development of a process model capable of describing more realistic BGA soldering scenarios. Process model predictions illustrate the system’s thermomechanical response to thermal and mechanical processing conditions, as well as component properties. High thermal conductivity assemblies show the greatest sensitivity to mechanical loading conditions.

scholarly journals Algorithms and models of power losses in circuit breakers installed in networks

Vestnik MGTU ◽  
2020 ◽  
Vol 23 (4) ◽  
pp. 345-353
Author(s):  
E. I. Gracheva ◽  
A. N. Gorlov ◽  
A. N. Alimova
Keyword(s):  
Power Supply ◽  
Low Voltage ◽  
Technical Condition ◽  
Active Power ◽  
Operating Conditions ◽  
Public Utility ◽  
Electrical Networks ◽  
Power Losses ◽  
Circuit Breakers ◽  
Technical Parameters

Determination of the main characteristics of the topology and technical condition of equipment underoperating conditions is necessary for analyzing and assessing power and electricity losses in intrashoplow-voltage industrial power supply networks. A comparative analysis of the technical characteristicsof automatic circuit breakers VA57-31 (KEAZ), NSX100 TM-D (Schneider Electric), DPX3 160 (Legrand), Tmax XT1 TMD (ABB) has shown that the main technical parameters of the machines are close in their values. At that it has been found out that automatic switches of the BA57-31 series have the lowest value of power losses per pole (7.5 W), whereas the automatic switches of the Tmax XT1 TMD series have the highest value (10 W). Thus, under the operating conditions of the equipment, the lowest value of power and electricity losses is characteristic of low-voltage electrical networks with installed circuit breakers of the BA57-31 series, and the highest value of losses is noted in in-shop systems with installed circuit breakers Tmax XT1 TMD. Using catalog data, the dependences of active power losses in circuit breakers on rated currents have been established; the algorithms have been developed and the obtained dependences have been modeled using approximating functions. The standard deviation of the compiled approximating functions has been calculated. Analytical expressions of the dynamics of power losses per pole have been determined as a function of the rated current. The graphical dependences of the investigated parameters of low-voltage equipment have been presented. The developed models are recommended to be used to increase the reliability of the assessment and refinement of the amount of active power and electricity losses in low-voltage electrical networks of industrial power supply systems, agrotechnical complexes, and enterprises of the public utility sector.

Hydrodynamic Lubrication and Wear in Wavy Contacting Face Seals

1978 ◽  
Vol 100 (1) ◽  
pp. 81-90 ◽  
Author(s):  
A. O. Lebeck ◽  
J. L. Teale ◽  
R. E. Pierce
Keyword(s):  
Surface Roughness ◽  
Hydrodynamic Lubrication ◽  
Surface Profile ◽  
Operating Conditions ◽  
Face Seal ◽  
Hydrodynamic Load ◽  
Surface Waviness ◽  
Wear Rates ◽  
Elastic Deflection ◽  
Face Seals

A model of face seal lubrication is proposed and developed. Hydrodynamic lubrication for rough surfaces, surface waviness, asperity load support, elastic deflection, and wear are considered in the model. Predictions of the ratio of hydrodynamic load support to asperity load support are made for a face seal sealing a low viscosity liquid where some contact does occur and surface roughness is important. The hydrodynamic lubrication is caused by circumferential surface waviness on the seal faces. Waviness is caused by initial out of flatness or any of the various distortions that occur on seal ring faces in operation. The equilibrium solution to the problem yields one dimensional hydrodynamic and asperity pressure distributions, mean film thickness, elastic deflection, and friction for a given load on the seal faces. The solution is found numerically. It is shown that the fraction of hydrodynamic load support depends on many parameters including the waviness amplitude, number of waves around the seal, face width, ring stiffness, and most importantly, surface roughness. For the particular seal examined the fraction of load support would be small for the amount of waviness expected in this seal. However, if the surface roughness were lower, almost complete lift-off is possible. The results of the analysis show why the initial friction and wear rates in mechanical face seals may vary widely; the fraction of hydrodynamic load support depends on the roughness and waviness which are not necessarily controlled. Finally, it is shown how such initial waviness effects disappear as the surface profile is altered by wear. This may take a long or short time, depending on the initial amount of hydrodynamic load support, but unless complete liftoff is achieved under all operating conditions, the effects of initial waviness will vanish in time for steady state conditions. Practical implications are drawn for selecting some seal parameters to enhance initial hydrodynamic load support without causing significant leakage.

scholarly journals Prediction of Low-Voltage Tetrafluoromethane Emissions Based on the Operating Conditions of an Aluminium Electrolysis Cell

JOM ◽  
2016 ◽  
Vol 68 (9) ◽  
pp. 2472-2482 ◽  
Author(s):  
Lukas Dion ◽  
László I. Kiss ◽  
Sándor Poncsák ◽  
Charles-Luc Lagacé
Keyword(s):  
Low Voltage ◽  
Operating Conditions ◽  
Electrolysis Cell ◽  
Aluminium Electrolysis

scholarly journals Fuzzy Logic Control for Low-Voltage Ride-Through Single-Phase Grid-Connected PV Inverter

Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4796 ◽  
Author(s):  
Eyad Radwan ◽  
Mutasim Nour ◽  
Emad Awada ◽  
Ali Baniyounes
Keyword(s):  
Fuzzy Logic ◽  
Output Power ◽  
Single Phase ◽  
Reactive Power ◽  
Low Voltage ◽  
Operating Conditions ◽  
Pv System ◽  
Utilization Factor ◽  
Low Voltage Ride Through ◽  
Active And Reactive Power

This paper presents a control scheme for a photovoltaic (PV) system that uses a single-phase grid-connected inverter with low-voltage ride-through (LVRT) capability. In this scheme, two PI regulators are used to adjust the power angle and voltage modulation index of the inverter; therefore, controlling the inverter’s active and reactive output power, respectively. A fuzzy logic controller (FLC) is also implemented to manage the inverter’s operation during the LVRT operation. The FLC adjusts (or de-rates) the inverter’s reference active and reactive power commands based on the grid voltage sag and the power available from the PV system. Therefore, the inverter operation has been divided into two modes: (i) Maximum power point tracking (MPPT) during the normal operating conditions of the grid, and (ii) LVRT support when the grid is operating under faulty conditions. In the LVRT mode, the de-rating of the inverter active output power allows for injection of some reactive power, hence providing voltage support to the grid and enhancing the utilization factor of the inverter’s capacity. The proposed system was modelled and simulated using MATLAB Simulink. The simulation results showed good system performance in response to changes in reference power command, and in adjusting the amount of active and reactive power injected into the grid.

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