Session: DA-01-02 Design & Analysis of Heat Exchangers & Components II

Paper Number: 62146

Start Time: Wednesday, July 14, 2021, 05:00 PM

62146 - Validation of Modern Finite Analysis Methods for Glassy Polymers Using Historical Studies 

The current method for designing acrylic pressure vessel components relies upon an empirical method developed through experimentation in the 1960-70’s.   The method is specified in ASME PVHO-1, Safety Standard for Pressure Vessels for Human Occupancy.  One of the factors for the restricting the design methodology to experimental correlation was the lack of a comprehensive calculation-based models used in conventional pressure vessels.   The relative strength of steel to acrylic dictated many of the designs would be less than the 10:1 “vessel radius” to “wall thickness” ratio that allows “thin wall” simplification methods.   This prevented the use of conventional Section VIII pressure vessel calculations.   Using early Finite Element Analysis (FEA) codes was attempted but often could not be validated through experimentation.   This was attributed to the nonlinear material properties of acrylics.   There is current an ASME Codes & Standards task group developing a “design by analysis” method (DBA)  for acrylics and other glassy polymers which uses current Verification & Validation (V&V) and modern FEA methods to provide an alternative design method in order to accommodate changes to materials and applications.  This paper re-examines the landmark work that was used to develop PVHO-1 to demonstrate modern nonlinear FEA and V&V techniques can predict the results of the original. In doing so, this work also validates the use of FEA going forward for newer materials, shapes, and applications.  One of the co-authors of this paper was part of the team conducting those studies over 40 years ago.

Presenting Author: Bart Kemper Kemper Engineering Services, LLC

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