scholarly journals Abstract Behavior Types: A Foundation Model for Components and Their Composition

Author(s):  
Farhad Arbab
Author(s):  
Gibin Gil ◽  
Sujin Lee

ABSTRACT In radial tires, belt structure plays a role of minimizing the lateral deflection of carcass, which has a significant influence on the cornering and wear properties of a tire. The deflection of carcass affects the magnitude of tread block deformation when the tire is under the slip angle. As a result, it can change the cornering stiffness characteristics of the tire, especially when the vertical load is high. During tire development, a tire design engineer tries to find the optimal belt ply angle that satisfies the various performance requirements simultaneously, but it is not an easy task because the effect of belt angle change is different depending on the size of the tire. There have been many attempts to construct a mathematical model that represents the structural properties of the belt package, including the string-based model and the beam on elastic foundation model. But, in many cases, only the in-plane bending of belt is considered and the shear deformation is not taken into consideration. In this study, the effect of belt angle change on belt stiffness is analyzed using a mathematical model based on the Timoshenko beam theory. This model can account for the in-plane bending and shear deformation of the belt structure at the same time. The results of the analysis show how the contribution of bending and shear is changed depending on a tire design parameter, herein the belt cord angle. The effect of belt ply angle change on cornering stiffness is investigated by means of the brush model including belt flexibility. The prediction by the brush model is compared with the measurement using a Flat-trac machine, and the validity of the model is discussed.


2017 ◽  
Vol 17 (4) ◽  
pp. 204-219 ◽  
Author(s):  
Éanna P. McKeon ◽  
Aidan M. O'Connell ◽  
Bryan A. McCabe
Keyword(s):  

Author(s):  
Shan Jiang ◽  
Xingji Wang

A mechanics-based model of flexible needle insertion into soft tissue is presented in this paper. Different from the existing kinematic model, a new model has been established based on the quasi-static principle, which also incorporates the dynamics of needle motions. In order to increase the accuracy of the model, nonlinear characteristics of the flexible needle and the soft tissue are both taken into account. The nonlinear Winkler foundation model and the modified Euler–Bernoulli theory are applied in this study, providing a theoretical framework to study insertion and deformation of needles. Galerkin method and iteration cycle analysis are applied in solving a series of deformation control equations to obtain the needle deflection. The parameters used in the mechanics-based model are obtained from the needle force and needle insertion experiment. Sensitivity studies show that the model can respond reasonably to changes in response to variations in different parameters. A 50 mm needle insertion simulation and a 50 mm corresponding needle insertion experiment are conducted to prove the validity of the model. At last, a study on different needle tip bevel demonstrates that the mechanics-based model can precisely predict the needle deflection when more than one parameter is changed. The solution can also be used in optimizing trajectory of the needle tip, enabling the needle to reach the target without touching important physiological structures such as blood vessels with the help of dynamic trajectory planning.


Author(s):  
Nguyen LaTray ◽  
Daejong Kim ◽  
Myongsok Song

Abstract This work presents a novel design of a hydrostatic thrust foil bearing (HSTFB) with an outer diameter of 154mm along with simulation and test results up to specific load capacity of 223kPa (32.3psi). The HSTFB incorporates a high pressure air/gas injection to the thrust foil bearing with a uniform clearance. This bearing has high load capacity, low power loss, and no friction/wear during startup and shutdown. In addition, the HSTFB allows for bidirectional operation. The paper also presents an advanced simulation model which adopts the exact locations of a tangentially arranged bumps to a cylindrical two-dimensional plate model of the top foil. This method predicts top foil deflection with better accuracy than the traditional independent elastic foundation model which distributes the bump locations over the nodal points in the cylindrical coordinates, and with less computational resource than the finite element method applied to the entire bump/top foils. The presented HSTFB, was designed for Organic Rankine Cycle (ORC) generators, but its performance was predicted and measured using air in this paper. The bearing static performance is compared analytically against the rigid counterpart, and presented at different supply pressures, speeds, and minimum film thicknesses. Experimental verification is conducted at 10, 15 and 20krpm. The measured load capacity and frictional loss agree well with the prediction. The measured film thickness also agrees with the prediction after the structural deflection of the thrust runner disc is compensated. Overall, the novel HSTFB demonstrates an excellent static performance and shows good potential for adoption to the intended ORC generators and other large oil-free turbomachines.


1977 ◽  
Vol 103 (2) ◽  
pp. 243-255
Author(s):  
Ish K. Aneja ◽  
Brian W. Dimmick

1983 ◽  
Vol 6 (2) ◽  
pp. 86-97 ◽  
Author(s):  
Ruth D. Handel

Ninety elementary school teachers responded to descriptions of gifted students by ranking the appropriateness of classroom actions categorized as “social relationship” or “academic challenge” interventions. The purpose of the study was to discover differences in classroom management of gifted girls, as compared to gifted boys or students not identified by sex on the stimulus material. Students were also described as either “conformist” or “assertive” behavior types. The research design was a 3 × 2 factorial analysis of variance with repeated measures on the second factor. Results indicated significantly more “social relationship” interventions for assertive than conformist gifted and significantly more “academic challenge” interventions for conformist than assertive gifted. No significant differences in classroom management of gifted girls appeared. Possible explanations include absence of sex stereotyping of the gifted and salience of giftedness, rather than sex, on the instrument used. Observational studies are proposed as measures of more subtle aspects of classroom management and possible divergence of written responses from actual behavior.


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