Finite Width Effects on the Critical Speed of Axially Moving Materials

1998 ◽  
Vol 120 (2) ◽  
pp. 633-634 ◽  
Author(s):  
C. C. Lin
Keyword(s):  
Critical Speed ◽  
Beam Theory ◽  
Axially Moving Beam ◽  
Finite Width ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Simply Supported ◽  
Moving Beam ◽  
Two Dimensional Model ◽  
Axially Moving

An exact solution is provided to determine the effects of the free end boundary conditions and the slenderness ratios on the critical speed of two dimensional, axially moving materials. The axially moving beam theory and the mathematical, two-dimensional model with all edges simply supported are also considered for comparison.

scholarly journals Frictionally Excited Thermoelastic Instability in Multi-Disk Clutches and Brakes

2000 ◽  
Vol 123 (4) ◽  
pp. 865-871 ◽  
Author(s):  
P. Decuzzi ◽  
M. Ciaverella ◽  
G. Monno
Keyword(s):  
Critical Speed ◽  
Finite Thickness ◽  
Thickness Ratio ◽  
Wave Parameter ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Thermoelastic Instability ◽  
Dimensional Plane ◽  
Two Dimensional Model ◽  
Radial Thickness

The propensity toward thermoelastic instability (TEI) in multi-disk clutches and brakes is investigated by introducing a new bidimensional analytical model, where metal and friction disks are replaced by two-dimensional layers of finite thickness. This new model permits to estimate the effect of the thickness ratio a1/a2, between friction and metal disks, on the critical speed, critical wave parameter and migration speed of the sliding system. It is found that as the thickness ratio a1/a2 decreases the critical speed reduces significantly taking up values about 80 percent smaller than that predicted by previous two-dimensional models for commonly used ratios 0.1<a1/a2<1, whilst the critical wave parameter slightly increases. Therefore, not only the susceptibility towards TEI can be reduced by changing the material properties of the friction lining but also by adjusting suitably the thickness ratio of the disks. The two-dimensional model is also employed to determine the critical speed in a real multi-disk clutch, and the results are compared with a three-dimensional finite element code. It is shown that the critical speed estimated by the present two-dimensional plane strain model is in good agreement with that determined by the FE code for sufficiently large radial thickness of the disks, whilst the two-dimensional plane stress solution has to be used for relatively small radial thickness ratios. Also, it is found that the critical number of hot spots is independent of the radial thickness ratio and it is correctly predicted by the two-dimensional model.

Commitment to pro- versus counter-attitudinal behavior and the dynamics of social representations

2002 ◽  
Vol 61 (1) ◽  
pp. 34-44 ◽  
Author(s):  
Eric Tafani ◽  
Lionel Souchet
Keyword(s):  
Higher Education ◽  
Social Representations ◽  
Cognitive Restructuring ◽  
Social Representation ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Social Actions ◽  
The Social ◽  
Two Dimensional Model ◽  
Students Attitudes

This research uses the counter-attitudinal essay paradigm ( Janis & King, 1954 ) to test the effects of social actions on social representations. Thus, students wrote either a pro- or a counter-attitudinal essay on Higher Education. Three forms of counter-attitudinal essays were manipulated countering respectively a) students’ attitudes towards higher education; b) peripheral beliefs or c) central beliefs associated with this representation object. After writing the essay, students expressed their attitudes towards higher education and evaluated different beliefs associated with it. The structural status of these beliefs was also assessed by a “calling into question” test ( Flament, 1994a ). Results show that behavior challenging either an attitude or peripheral beliefs induces a rationalization process, giving rise to minor modifications of the representational field. These modifications are only on the social evaluative dimension of the social representation. On the other hand, when the behavior challenges central beliefs, the same rationalization process induces a cognitive restructuring of the representational field, i.e., a structural change in the representation. These results and their implications for the experimental study of representational dynamics are discussed with regard to the two-dimensional model of social representations ( Moliner, 1994 ) and rationalization theory ( Beauvois & Joule, 1996 ).

Pulse Antennas: Accurate Solution of Two-Dimensional Model Problems for Structures with Gratings as Dispersive Elements

2001 ◽  
Vol 55 (8) ◽  
pp. 14
Author(s):  
A. I. Vyazmitinova ◽  
V. L. Pazynin ◽  
Andrei Olegovich Perov ◽  
Yurii Konstantinovich Sirenko ◽  
H. Akdogan ◽  
...  
Keyword(s):  
Accurate Solution ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Two Dimensional Model
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