Lifting-Line Analysis of Wing Twist to Minimize Induced Drag During Pure Rolling Motion

Author(s):  
Douglas F. Hunsaker ◽  
Zachary S. Montgomery ◽  
James J. Joo
Author(s):  
Christina Harvey ◽  
Vikram B. Baliga ◽  
Douglas L. Altshuler ◽  
Daniel J. Inman

2002 ◽  
Vol 124 (3) ◽  
pp. 595-599 ◽  
Author(s):  
Bo Jacobson

It is today possible to manufacture so smooth surfaces that they can elastically conform totally to each other over the whole Hertzian contact area. For pure rolling lubrication such surfaces only need an oil film of molecular dimensions to get total separation. When the rolling motion is combined with sliding, the pressure fluctuations inside the Hertzian contact redistribute the oil and make metal-to-metal contact possible. The redistribution velocity is a function of the slip rate S and the number of asperities N from the inlet to the outlet of the Hertzian contact area. The asperity top oil film thickness decreases with a factor of the order 2NS going from the inlet to the outlet of the Hertzian contact.


2004 ◽  
Vol 41 (5) ◽  
pp. 1169-1176 ◽  
Author(s):  
W. F. Phillips ◽  
N. R. Alley ◽  
W. D. Goodrich

2013 ◽  
Vol 50 (4) ◽  
pp. 1226-1233 ◽  
Author(s):  
W. F. Phillips ◽  
D. F. Hunsaker

2015 ◽  
Vol 798 ◽  
pp. 565-570
Author(s):  
Luciano Magno Fragola Barbosa ◽  
Ricardo Luiz Utsch de Freitas Pinto ◽  
Bernardo Oliveira Hargreaves

In this work improvements on the geometry of a high aspect ratio aircraft wing are studied, in order to reduce the wing in-flight deformation, without changing the drag of the aircraft and without increasing the structural weight. For this, from a reference rectangular wing, one new wing with elliptical planform has been defined; and comparative analyses of loads and structural deformation have been made for the wings considered: the original rectangular wing and the new corresponding elliptical wing. The aerodynamic analysis is based on the lifting line approach. A computer routine is made by the authors based on this approach, to obtain both induced drag values and the load distribution of the two wings, the original one and the corresponding elliptical. Based on the loads, spars for the two wings have been defined, and in order to evaluate the vertical displacements in flight, a finite element routine have been used. The main result of this study is the comparison of the deformation of wings considered, subjected to the same load factor, and for the same aircraft mass. The results obtained are encouraging for further developments using the present methodology.


2005 ◽  
Vol 128 (4) ◽  
pp. 710-718 ◽  
Author(s):  
D. Chablat ◽  
J. Angeles

The design of a novel prismatic drive is reported in this paper. This transmission is based on Slide-o-Cam, a cam mechanism with multiple rollers mounted on a common translating follower. The design of Slide-o-Cam was reported elsewhere. This drive thus provides pure-rolling motion, thereby reducing the friction of rack-and-pinions and linear drives. Such properties can be used to design new transmissions for parallel-kinematics machines. In this paper, this transmission is intended to replace the ball-screws in Orthoglide, a three-dof parallel robot intended for machining applications.


2010 ◽  
Vol 47 (6) ◽  
pp. 2119-2129 ◽  
Author(s):  
Timm Junge ◽  
Frederik C. Gerhardt ◽  
Peter Richards ◽  
Richard G. J. Flay
Keyword(s):  

Author(s):  
Giorgio Figliolini ◽  
Paolo Migliozzi

A general formulation for the synthesis of the pitch cones of N-lobed elliptical bevel gears and the pitch surface of their conjugate crown-rack is proposed. In particular, both pitch cones and the pitch surface of their crown-rack can be obtained for any number and combination of lobes and in any configuration during their pure-rolling motion. This formulation has been implemented in a suitable Matlab program and several significant examples are shown, where circular bevel gears become a particular case. Computer animations are also available at URL: http://webuser.unicas.it/weblarm/larmindex.htm.


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