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

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.

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Three-Dimensional Simulations of Blood Flow With Systemic Arterial Baroreflex

ASME 2009 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2009-206221 ◽

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.

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