Three-Dimensional Simulations of Blood Flow With Systemic Arterial Baroreflex

2009 ◽  
Author(s):  
H. J. Kim ◽  
C. A. Taylor
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Closed Loop ◽  
Three Dimensional ◽  
Element Model ◽  
Loop System ◽  
Loop Model ◽  
Arterial Baroreflex ◽  
Closed Loop System ◽  
Venous Compliance

The systemic arterial baroreflex controls the systemic arterial pressure to maintain homeostasis. The carotid sinus and aortic arch are the major systemic arterial baroreceptors, and they respond to distention of the carotid and aortic walls causing compensatory mechanisms, which regulate heart rate, cardiac contractility, peripheral arterial resistance, venous compliance, and venous unstressed volume [1]. In this study, we connect a feedback control loop, which represents the systemic arterial baroreflex, to the closed loop system we developed in a previous study [2]. The three-dimensional finite element model of the aorta and the closed loop system enable us to obtain not only the physiologic flow rate and pressure fields of the finite element model but also the global characteristics of the cardiovascular system from the closed loop model. We study the autoregulatory mechanisms occurring due to the systemic arterial baroreflex by considering the interactions between the heart and the systemic and pulmonary circulations.

Torsional Analysis of a Steel Cord-Rubber Tire Belt Structure

1996 ◽  
Vol 24 (4) ◽  
pp. 339-348 ◽  
Author(s):  
R. M. V. Pidaparti
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Composite Structures ◽  
Three Dimensional ◽  
Element Model ◽  
Torsional Stiffness ◽  
Element Analysis ◽  
Rubber Belt ◽  
Steel Cord ◽  
Torsional Analysis

Abstract A three-dimensional (3D) beam finite element model was developed to investigate the torsional stiffness of a twisted steel-reinforced cord-rubber belt structure. The present 3D beam element takes into account the coupled extension, bending, and twisting deformations characteristic of the complex behavior of cord-rubber composite structures. The extension-twisting coupling due to the twisted nature of the cords was also considered in the finite element model. The results of torsional stiffness obtained from the finite element analysis for twisted cords and the two-ply steel cord-rubber belt structure are compared to the experimental data and other alternate solutions available in the literature. The effects of cord orientation, anisotropy, and rubber core surrounding the twisted cords on the torsional stiffness properties are presented and discussed.

Reduction of Free-Edge Stress Concentration

1985 ◽  
Vol 52 (4) ◽  
pp. 801-805 ◽  
Author(s):  
P. R. Heyliger ◽  
J. N. Reddy
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Element Model ◽  
Free Edge ◽  
Shear Stresses ◽  
Normal Stresses ◽  
Interlaminar Shear ◽  
Three Dimensional Elasticity

A quasi-three dimensional elasticity formulation and associated finite element model for the stress analysis of symmetric laminates with free-edge cap reinforcement are described. Numerical results are presented to show the effect of the reinforcement on the reduction of free-edge stresses. It is observed that the interlaminar normal stresses are reduced considerably more than the interlaminar shear stresses due to the free-edge reinforcement.

scholarly journals Flexible Die Design and Springback Compensation Based on Modified Displacement Adjustment Method

2014 ◽  
Vol 6 ◽  
pp. 131253 ◽  
Author(s):  
Young-Ho Seo ◽  
Ji-Woo Park ◽  
Woo-Jin Song ◽  
Beom-Soo Kang ◽  
Jeong Kim
Keyword(s):  
Closed Loop ◽  
Three Dimensional ◽  
Loop System ◽  
Die Design ◽  
Manufacturing Cost ◽  
Closed Loop System ◽  
Forming Process ◽  
Element Analysis ◽  
Springback Compensation ◽  
Flexible Die

Springback in metal forming process often results in undesirable shape changes in formed parts and leads to deterioration in product quality. Even though springback can be predicted and compensated for through the theories or methodologies established thus far, an increase in manufacturing cost accompanied by a change in die shape is inevitable. In the present paper, it is suggested that the cost accompanied with springback compensation can be minimized while allowing the processing of various three-dimensional curved surfaces by using a flexible die composed of multiple punches. With the die being very flexible, the iterative trial-and-error method can be readily applied to compensate for the springback. Thus, repeated designing and redesigning of solid or matched dies can be avoided, effectively saving considerable time. Only some adjustments of punch height are required. Detailed designs of the flexible die as well as two core algorithms to control the respective punch heights are described in this paper. In addition, a closed-loop system for the springback compensation using the flexible die is proposed. The amount of springback was simulated by a finite element analysis and the modified displacement adjustment (DA) method as the springback compensation model was used in the closed-loop system. This system was applied to a two-dimensional quadratic shape problem, and its robustness was verified by an experiment.

scholarly journals Numerical investigation of plastic flow and residual stresses generated in hydroformed tubes

2021 ◽  
pp. 146442072198974
Author(s):  
A Ktari ◽  
A Abdelkefi ◽  
N Guermazi ◽  
P Malecot ◽  
N Boudeau
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Finite Element Model ◽  
Plastic Flow ◽  
Tube Hydroforming ◽  
Three Dimensional ◽  
Element Model ◽  
Tube Cross Section ◽  
Straight Wall ◽  
Hydroforming Process

During tube hydroforming process, the friction conditions between the tube and the die have a great importance on the material plastic flow and the distribution of residual stresses of the final component. Indeed, a three-dimensional finite element model of a tube hydroforming process in the case of square section die has been performed, using dynamic and static approaches, to study the effect of the friction conditions on both plastic flow and residual stresses induced by the process. First, a comparative study between numerical and experimental results has been carried out to validate the finite element model. After that, various coefficients of friction were considered to study their effect on the thinning phenomenon and the residual stresses distribution. Different points have been retained from this study. The thinning is located in the transition zone cited between the straight wall and the corner zones of hydroformed tube due to the die–tube contact conditions changes during the process. In addition, it is clear that both die–tube friction conditions and the tube bending effects, which occurs respectively in the tube straight wall and corner zones, are the principal causes of the obtained residual stresses distribution along the tube cross-section.

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