will increase the efficiency of the design of horizontal pressure vessels. ... main vessel components [13-15]. The codes ...... Design, J. S. Gero, ed., North-Holland, 1985. ... 19 Pressure Vessel Design ProgramâPVD User Manual, Bechtel Corp.,.
N. Nguyen Stress Analyst. Bechtel Energy Corporation, Houston, TX 77056
F. Mistree Associate Professor. Department of Mechanical Engineering, University of Houston, Houston, TX 77004
Design of Horizontal Pressure Vessels Using the Decision Support Problem Technique A design method has been developed to determine systematically the system variables that will best achieve multiple design objectives involving both cost and damage tolerance of horizontal vessel design. The method is computer based, and is particularly suited for designing pressure vessels using multiple (conflicting) objectives. The method has been tested and validated against a computer program used extensively in industry. Better results by the new design method are demonstrated through case studies. The results indicate a wide range of vessel dimensions to which the design method can be applied. In general, application of the method will increase the efficiency of the design of horizontal pressure vessels.
1 Overview of Horizontal Pressure Vessel Design Large horizontal pressure vessels (Fig. 1) are commonly used in industry for the purpose of product storage and other process functions. As the name implies, the main purpose of pressure vessels is to contain a fluid under pressure and temperature. In so doing, they are subject to the action of support loading, pressure loading and piping reaction, all of which require an overall knowledge of the stresses imposed by different loading conditions on various vessel components. Various codes governing the procedures for the design, fabrication, inspection, testing and operation of pressure vessels have been developed in many countries around the world [16]. These procedures furnish the standards by which the regulatory authority of any country or state can be assured of the safety of pressure vessels installed within its boundary. The code used for pressure vessels in the United States is Section viii, Division 1, of the ASME Boiler and Pressure Vessel Code [14]. Many states require that pressure vessels be designed and fabricated according to these specifications. Further, it is necessary in some states that pressure vessels be designed to the code specifications in order to obtain insurance on the plant in which the vessels are to be used. Design of pressure vessels thus has to be done in accordance with specific codes which give formulas, rules and specifications for satisfactory and safe construction of the main vessel components [13-15]. The codes, however, leave it up to the designer to decide what method or methods should be used to solve specific design problems. Up to now, the pressure vessel engineers have by and large not made use of any systematic rational design procedure. The engineer is often asked to check the structural adequacy of the vessel components before the design is finalized. However, with the ever-increasing capability of the computer to interact with the
engineer in the design-analysis cycle, a computer-based rational design method should now be an achievable goal. The rational design method presented in this paper involves the formulation of a suitable design procedure to determine systematically the system variables that will best achieve a set of specified design goals, within the assumptions imposed on the system. The development of the rational design method for pressure vessels is a complex task involving three phases: Structural analysis, to determine the response of the pressure vessel to multiple load combinations; analysis of failure modes and stresses in various vessel components defines the system constraints on the design for maintaining structural integrity of the pressure vessel. Cost analysis of the vessel components, to determine the total fabrication cost for economic consideration in the design process. Development of a design synthesis methodology, to solve the resulting decision support problem. A design method called Automated .Design of Fessel as an Advanced Nonlinear ly Constrained Engineering System (ADVANCES) has been developed for the design of horizontal pressure vessels and is presented in this paper. The effectiveness of this method will be tested against a commercial computer program in postsolution analyses. Also, Head Tangent Line ^Hea
0
(18)
Design of the head for external pressure: PAH-PE>0
(19)
PAS-PE>0 (16)
A2XLE
Local stress reduction, and fabrication ease: TO-73
(20)
+ 0.125 > 0
Minimum thickness for the wear plate: TP-TS>0
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