29-04-2017, 09:20 AM
The following material only represents the author and should not be assumed to be the opinion or policy of the National Board of Boiler and Pressure Vessel Instructors or the management, personnel or membership of the American Society of Mechanical Engineers, unless So be recognized.
The use of finite element methods to design and analyze pressure vessels is a relatively recent development in the overall historical perspective of the ASME Code. The finite element method became for the first time a useful tool for the designer in the early 1960s. The advent of the ASME Nuclear Code, Section III, which first appeared in 1964, provided for a "design by analysis" procedure. Up to this point, all PSC codes used the "formula design" approach, which is essentially that which is now used in Section VIII, Division 1 of the ASME Code. The formula design method provides explicit rules for calculating head wall thicknesses, housings, reinforcement around apertures, and other details of a vessel. There are additional rules for handling characteristics such as discontinuities between different components (ie the 3: 1 taper rule) and allowable construction details are illustrated. The drawback of these rules is, of course, that they can not cover every conceivable detail that the designer may want to use. For example, Section VIII, Division 1, gives numerous warnings and warnings that the designer should consider the effects of thermal gradients, pipe loads, nozzle loads, rapid fluctuation loads, seismic, wind, etc., but unfortunately exist Few guidelines or specific formulas included in the code to cover such items. In addition, the permissible stresses given in the code are based on a rather simplistic average membrane stress. Other loads, such as thermal loads, for example, cause a different type of stress that can not be limited to the S values in the code if a reasonable design is to be developed.
Section III and Section VIII, Division 2, which came out several years after Section III, both use the concept of design by analysis. These rules provide the designer / analyst with a variety of stress limits, each developed to protect against a different mode of failure. Stress is categorized as Primary, Secondary, Peak, etc. Each category of stress is subject to different stress limits. Essentially, the Nuclear Code and Division 2 of Section VIII require the designer / analyst to be able to calculate tensions throughout the vessel, not only the average membrane stresses in regular sections (such as cylinders and bulged heads) .
A literature review of finite element methods (FEM) applied for analysis of structures / components of pressure vessels and pipelines from a theoretical and practical point of view. This bibliography is a new addition to the finite elements in the analysis of pressure vessels and pipes - a bibliography 1; 2; 3. The lists at the end of the document contain 856 references to documents and conference proceedings on the subject that were published in 2001-2004. They are classified into the following categories: linear and nonlinear, static and dynamic analysis, stress and deflection analysis; Stability problems; Thermal problems; Problems of mechanics of the fracture; Contact problems; Fluid-structure interaction problems; Manufacture of tubes and pipes; Welded pipes and components of pressure vessels; Development of special finite elements for pressure vessels and pipes; Finite element software; And other topics.
The use of finite element methods to design and analyze pressure vessels is a relatively recent development in the overall historical perspective of the ASME Code. The finite element method became for the first time a useful tool for the designer in the early 1960s. The advent of the ASME Nuclear Code, Section III, which first appeared in 1964, provided for a "design by analysis" procedure. Up to this point, all PSC codes used the "formula design" approach, which is essentially that which is now used in Section VIII, Division 1 of the ASME Code. The formula design method provides explicit rules for calculating head wall thicknesses, housings, reinforcement around apertures, and other details of a vessel. There are additional rules for handling characteristics such as discontinuities between different components (ie the 3: 1 taper rule) and allowable construction details are illustrated. The drawback of these rules is, of course, that they can not cover every conceivable detail that the designer may want to use. For example, Section VIII, Division 1, gives numerous warnings and warnings that the designer should consider the effects of thermal gradients, pipe loads, nozzle loads, rapid fluctuation loads, seismic, wind, etc., but unfortunately exist Few guidelines or specific formulas included in the code to cover such items. In addition, the permissible stresses given in the code are based on a rather simplistic average membrane stress. Other loads, such as thermal loads, for example, cause a different type of stress that can not be limited to the S values in the code if a reasonable design is to be developed.
Section III and Section VIII, Division 2, which came out several years after Section III, both use the concept of design by analysis. These rules provide the designer / analyst with a variety of stress limits, each developed to protect against a different mode of failure. Stress is categorized as Primary, Secondary, Peak, etc. Each category of stress is subject to different stress limits. Essentially, the Nuclear Code and Division 2 of Section VIII require the designer / analyst to be able to calculate tensions throughout the vessel, not only the average membrane stresses in regular sections (such as cylinders and bulged heads) .
A literature review of finite element methods (FEM) applied for analysis of structures / components of pressure vessels and pipelines from a theoretical and practical point of view. This bibliography is a new addition to the finite elements in the analysis of pressure vessels and pipes - a bibliography 1; 2; 3. The lists at the end of the document contain 856 references to documents and conference proceedings on the subject that were published in 2001-2004. They are classified into the following categories: linear and nonlinear, static and dynamic analysis, stress and deflection analysis; Stability problems; Thermal problems; Problems of mechanics of the fracture; Contact problems; Fluid-structure interaction problems; Manufacture of tubes and pipes; Welded pipes and components of pressure vessels; Development of special finite elements for pressure vessels and pipes; Finite element software; And other topics.