Engineered Materials. VIII

N. Faur, C. Bortun, L. Marsavina et al. (2010). Durability Studies for Complete Dentures, ADVANCES IN FRACTURE AND DAMAGE MECHANICS VIII, Key Engineering Materials, Vol. 417-418, 725-728 p. 

In the United Kingdom all conventional pressure vessels for use in the chemical and allied industries will invariably be designed and fabricated according to the British Standard PD 5500 or the European Standard EN 13445 or an equivalent code such as the American Society of Mechanical Engineers code Section VIII (the ASME code). The codes and standards cover design, materials of construction, fabrication (manufacture and... 

Table VIII summarizes major legislation which impacts the chemical industry with society s expectations for safe materials and a clean environment. The chemical engineer has a vital role to play in assuring that products meet these requirements.

General Considerations Most pressure vessels for the chemical-process industry will continue to be designed and built to the rules of Sec. VIII, Division 1. While the rules of Sec. VIII, Division 2, will frequently provide thinner elements, the cost of the engineering analysis, stress analysis and higher-quality construction, material control, and inspection required by these rules frequently exceeds the savings from the use of thinner walls. 

In addition to the BPV Code Sec. VIII, the process design engineer will frequently need to consult Section II Part D, which lists maximum allowable stress values under Sec. VIII D.l and D.2, as well as other materials properties. A comprehensive review of the ASME code is given by Chuse and Carson (1992) and Yokell (1986) see also Perry and Green (1997). 

Tables VII and VIII sumnarize present and future RIM engineering plastic developments. This is an emerging area for RIM processable materials part of which will be made possible by recent equipment developments such as hot RIM. Polyurethane materials which now exist in this hard segment range are plastics...

Engineering codes such as ASME B31.3 [4] for piping and ASME Section VIII, Div. 1 [1] for vessels contain provisions for creep design. If creep is a concern, coarse grained materials are favored. Carbon steels killed with silicon are usually recommended when creep is a concern, e.g., ASTM A106 for pipe and ASTM A515 for plate. 

Two basic theories of failure are used in the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, Section I, Section IV, Section 111 Division 1 (Subsections NC, ND, and NE), and Section VIII Division 1 use the maximum principal stress theory. Section ni Division 1 (Subsection NB and the optional part of NC) and Section VIII Division 2 use the maximum shear stress theory or the Tresca criterion. The maximum principal stress theory (sometimes called Rankine theory) is appropriate for materials such as cast iron at room temperature, and for mild steels at temperatures below the nil ductility transition (NDT) temperature (discussed in Section 3.7). Although this theory is used in some design codes (as mentioned previously) the reason is that of simplicity, in that it reduces the amount of analysis, although often necessitating large factors of safety. 

Figure 11.4 Methods of adding reinforcement material. (Courtesy American Society of AAechanicat Engineers, From Fig. UW-16.1 of the ASME Code, VIII-1)...

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