scholarly journals SURFACE ROUGHNESS PARAMETER AND SLIP COEFFICIENT OF FRICTION TYPE OF HIGH STRENGTH BOLTED CONNECTIONS

2011 ◽  
Vol 67 (2) ◽  
pp. 446-453 ◽  
Author(s):  
Takeshi MORI ◽  
Kohsuke TASAKA ◽  
Mitsuru ICHIMIYA ◽  
Teruo OGASAWARA
Keyword(s):  
Surface Roughness ◽  
Coefficient Of Friction ◽  
Roughness Parameter ◽  
High Strength ◽  
Slip Coefficient ◽  
Bolted Connections ◽  
Surface Roughness Parameter

Surface Roughness at Wire Electrical Discharge Machining

2015 ◽  
Vol 760 ◽  
pp. 551-556 ◽  
Author(s):  
Oana Dodun ◽  
Laurenţiu Slătineanu ◽  
Margareta Coteaţă ◽  
Vasile Merticaru ◽  
Gheorghe Nagîţ
Keyword(s):  
Surface Roughness ◽  
Empirical Model ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Roughness Parameter ◽  
Wire Electrical Discharge Machining ◽  
Power Type ◽  
Surface Roughness Parameter ◽  
Pulse On Time ◽  
Pulse Off Time

Wire electrical discharge machining is a machining method by which parts having various contours could be detached from plate workpieces. The method uses the electrical discharges developed between the workpiece and the wire tool electrode found in an axial motion, when in the work zone a dielectric fluid is recirculated. In order to highlight the influence exerted by some input process factors on the surface roughness parameter Ra in case of a workpiece made of an alloyed steel, a factorial experiment with six independent variables at two variation levels was designed and materialized. As input factors, one used the workpiece thickness, pulse on time, pulse off-time, wire axial tensile force, current intensity average amplitude defined by setting button position and travelling wire electrode speed. By mathematical processing of the experimental results, empirical models were established. Om the base of a power type empirical model, graphical representations aiming to highlight the influence of some input factors on the surface roughness parameter Ra were achieved. The power type empirical model facilitated establishing of order of factors able to exert influence on the surface roughness parameter Ra at wire electrical discharge machining.

scholarly journals Coastal Boundary Layer Characteristics of Wind, Turbulence, and Surface Roughness Parameter over the Thumba Equatorial Rocket Launching Station, India

2014 ◽  
Vol 2014 ◽  
pp. 1-21 ◽  
Author(s):  
K. V. S. Namboodiri ◽  
Dileep Puthillam Krishnan ◽  
Rahul Karunakaran Nileshwar ◽  
Koshy Mammen ◽  
Nadimpally Kiran kumar
Keyword(s):  
Boundary Layer ◽  
Surface Roughness ◽  
Wind Direction ◽  
Roughness Parameter ◽  
Turbulent Heat ◽  
Surface Roughness Parameter ◽  
South West Monsoon ◽  
Wind Turbulence ◽  
Coastal Boundary Layer ◽  
Coastal Boundary

The study discusses the features of wind, turbulence, and surface roughness parameter over the coastal boundary layer of the Peninsular Indian Station, Thumba Equatorial Rocket Launching Station (TERLS). Every 5 min measurements from an ultrasonic anemometer at 3.3 m agl from May 2007 to December 2012 are used for this work. Symmetries in mesoscale turbulence, stress off-wind angle computations, structure of scalar wind, resultant wind direction, momentum flux (M), Obukhov length (L), frictional velocity (u*), w-component, turbulent heat flux (H), drag coefficient (CD), turbulent intensities, standard deviation of wind directions (σθ), wind steadiness factor-σθ relationship, bivariate normal distribution (BND) wind model, surface roughness parameter (z0), z0 and wind direction (θ) relationship, and variation of z0 with the Indian South West monsoon activity are discussed.

Considerations Regarding Some Surface State Parameters Characterized by a more Restricted Use

2015 ◽  
Vol 809-810 ◽  
pp. 93-98
Author(s):  
Ionuţ Urzică ◽  
Ciprian Râznic ◽  
Mihai Apostol ◽  
Corina Mihaela Pavăl ◽  
Mihai Boca ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Roughness Parameter ◽  
Cutting Speed ◽  
Roughness Parameters ◽  
Turning Process ◽  
Nose Radius ◽  
Machined Surface ◽  
Surface Roughness Parameter ◽  
Surface Roughness Parameters ◽  
Restricted Use

Frequently, on the drawings of mechanical parts, only indications concerning the surface roughness parameter Ra and, relatively rarely, the surface roughness parameter Rz are included. However, the study of the machined surface roughness highlights the necessity to use yet other surface roughness parameters, in order to have a clearer image on the state of the machined surface. Some other surface roughness parameters possible to be used and presenting importance, without the parameters Ra and Rz, were highlighted. One took into consideration the possibility of measuring parameters Rsk and Rmr by means of the available surface roughness testers. Experimental researches of turning by applying the method of full factorial experiment were developed. As input factors in turning process, the cutting speed, the feed rate and the tool nose radius were used. The experimental results were mathematically processed, being determined empirical mathematical models that highlight the influence of certain input factors of turning process on the values of some surface roughness parameters characterized by a more restricted use

Adaptive Control System to Assist the Surface Workpiece Quality when Drilling

2014 ◽  
Vol 474 ◽  
pp. 212-217 ◽  
Author(s):  
Marek Vrabel' ◽  
Ildikó Maňková ◽  
Jozef Beňo ◽  
Ladislav Kandráč ◽  
Jozef Stahovec
Keyword(s):  
Surface Roughness ◽  
Adaptive Control ◽  
Control System ◽  
Roughness Parameter ◽  
Cutting Speed ◽  
Constructional Material ◽  
Drilling Process ◽  
Adaptive Control System ◽  
Monitoring And Control ◽  
Surface Roughness Parameter

Article deals with design of adaptive control system for drilling process of aerospace critical components. The system proposed in this paper is directed towards real the time control of surface roughness parameter Ra. Proposed model for monitoring and control consists of surface roughness prediction system and decision making subsystem. The artificial neural network was employed to calculate surface roughness parameter Ra through of process monitoring indices such as torque Mz, force Fz, power P and cutting conditions feed f, cutting speed vc. Test samples were nickel based super alloy Udimet 720 used as a basic constructional material of discs for gas turbine engines.

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