Topic
Rotational speed
About: Rotational speed is a research topic. Over the lifetime, 23327 publications have been published within this topic receiving 151696 citations. The topic is also known as: speed of revolution & revolution rate.
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TL;DR: In this paper, the effect of process parameters such as tool rotation and weld speed on temperature distribution and mechanical properties of aluminum alloy AA2014 joined by friction stir welding was investigated using a three dimensional transient thermal model using finite element code ANSYS to quantify the thermal history.
84 citations
TL;DR: In this article, an experimental investigation of the aerodynamic performance of a high-solidity Wells turbine for a wave power plant is presented, and the results show that the presence of guide vanes can provide a remarkable increase in turbine efficiency.
Abstract: The paper describes an experimental investigation, and presents the results of the aerodynamic performance of a high-solidity Wells turbine for a wave power plant. A monoplane turbine of 0.6 m rotor diameter with guide vanes was built and tested. The tests were conducted in unidirectional steady airflow. Measurements taken include flow rate, pressure drop, torque, and rotational speed, as well as velocity and pressure distributions. Experimental results show that the presence of guide vanes can provide a remarkable increase in turbine efficiency.
84 citations
TL;DR: In this article, the effect of welding speed, rotation speed, plunge depth, and shoulder diameter on the formation of internal defects during friction stir welding (FSW) was analyzed and a simple criterion to identify defect-free weld formation was proposed.
Abstract: Welding parameters like welding speed, rotation speed, plunge depth, shoulder diameter etc., influence the weld zone properties, microstructure of friction stir welds, and forming behavior of welded sheets in a synergistic fashion. The main aims of the present work are to (1) analyze the effect of welding speed, rotation speed, plunge depth, and shoulder diameter on the formation of internal defects during friction stir welding (FSW), (2) study the effect on axial force and torque during welding, (c) optimize the welding parameters for producing internal defect-free welds, and (d) propose and validate a simple criterion to identify defect-free weld formation. The base material used for FSW throughout the work is Al 6061T6 having a thickness value of 2.1 mm. Only butt welding of sheets is aimed in the present work. It is observed from the present analysis that higher welding speed, higher rotation speed, and higher plunge depth are preferred for producing a weld without internal defects. All the shoulder diameters used for FSW in the present work produced defect-free welds. The axial force and torque are not constant and a large variation is seen with respect to FSW parameters that produced defective welds. In the case of defect-free weld formation, the axial force and torque are relatively constant. A simple criterion, (a,tau/a,p)(defective) > (a,tau/a,p)(defect free) and (a,F/a,p)(defective) > (a,F/a,p)(defect free), is proposed with this observation for identifying the onset of defect-free weld formation. Here F is axial force, tau is torque, and p is welding speed or tool rotation speed or plunge depth. The same criterion is validated with respect to Al 5xxx base material. Even in this case, the axial force and torque remained constant while producing defect-free welds.
84 citations
TL;DR: In this paper, the elastic and plastic limit angular velocities of rotating disks of variable thickness in power function form were calculated using the Von Mises yield criterion and its flow rule.
83 citations
Patent•
06 Dec 1990
TL;DR: In this paper, a rotational, chip cutting machine tool cutting at a predetermined depth on a workpiece in which the speed of rotation of the cutting tool relative to the workpiece and the rate of speed of the machine's cutting operation are both adjustably controlled between predetermined minimum and maximum rates for the particular combination of machine tool and workpiece material.
Abstract: A method of controlling chatter in a rotating, chip cutting machine tool cutting at a predetermined depth on a workpiece in which the speed of rotation of the cutting tool relative to the workpiece and the rate of speed of the cutting tool relative to the workpiece both adjustably controlled between predetermined minimum and maximum rates for the particular combination of machine tool and workpiece material. The method includes the steps of detecting vibration signals representative of relative vibrations between the machine tool and the workpiece and generated by preliminary operation of the machine tool at predetermined conditions, processing that generated signal as a function of signal frequency, obtaining a signal indicative of the rotational speed and determinating the threshold of the signal level above which are excluded harmonics of the predetermined rotational frequencies that are indicative of chatter in the cutting tool. Additional steps interrupt the feed of the cutting tool and change the speed of rotation if operationally generated audio signal levels exceed a threshold and then change the speed of rotation of the cutting tool and resume the feed of cutting engagement. These steps are repeated until operation of the machine tool is obtained without operationally generated chatter signals exceeding the threshold or, when necessary, reducing the speed of rotation and the rate of feed to predetermined levels known to avoid generation of chatter signals in excess of the threshold.
83 citations