STRESS ANALYSIS OF PIPE SUPPORT ATTACHMENTS: A COMPARISON OF ANALYTICAL METHODS AND FINITE ELEMENT ANALYSIS FOR CIRCULAR AND NON-CIRCULAR ATTACHMENTS

摘要

Despite the availability of special purpose FE codes with post processing facilities as per rules of ASME SEC VIII Division 2, use of simple analytical methods like ring loading around a circumference or more complex methods like Welding Research council bulletins 107 and 297, will continue to be used in the industry for a significant period of time for stress analysis of pipe support attachments. The reasons are few: not all engineering companies have such custom made FE codes, lack of trained personnel to work with general purpose FE codes, ease of implementation of the available methods and their successful design history, cost and time issues with FE analysis etc. In this paper these available methods will be reviewed based on their theoretical background, their range of applicability w.r.t the typical design parameters and their comparison with FE analysis. More recent analytical methods based on mathematically accurate space curves of intersections for circular attachments will also be discussed. This study will include both circular as well as non-circular attachments. This paper will highlight the strengths and weaknesses of the conventionally used methods especially with respect to their mathematical limitations to make an analyst aware of the potential over conservatism and under conservatism of these analytical methods. Finite element analysis models will be discussed in detail specifically in relation to elements used, element parameters, boundary conditions and post processing.