Dynaflow RESEARCH GROUP
This training seminar focusses on the latest information on Stress Intensification Factors (SIFs), flexibility factors (k-factors) and Sustained Stress Indices (SSIs) used in the ASME B31.3 design code and how to easily implement this for your pipe stress analysis using FEATools. Learn to understand the backgrounds of recent research and see how these developments impact your stress assessment!
- Outline of latest info on the state of SIFs, k-factors, and SSIs.
- SIF/k/SSI changes and the impact on bends – and how they affect the pipe stress
- Collapse of straight pipe and desired changes
- Impact of pressure on SIFs and the contradictory results given by different solution methods in VIII-2 Part 5.
- Optimizing Workflow and the pipe stress design process
- Allowable loads on pipe shoes – what affects allowable loads and how are they automatically reviewed
- API 661 header boxes, or rectangular constructions with nozzles attached.
- SIFs, k’s, SSIs and allowable loads for all types of vessel connections, i.e.
- Dished, Elliptical, Conical, Spherical, or Flat Heads
- Nozzles in heads with offsets and repads
- Using NozzlePRO allowable loads in FEATools automatically via FEATools
- Multiple outputs and comparing results from any number of CAESAR model calculations.
- Other Tools and Approaches:
- Laser Scanning and Model Validation
- POD – Improving probability of detection for inspection planning.
- Some simple approaches and guidelines for AIV (Continued with NozzlePRO discussion).
Commonly piping networks are modelled using beam type models with the stresses and flexibilities at discontinuities being calculated using empirical relationships, such as those found in ASME B31.3 Appendix D. These relationships provide the relevant Stress Intensification Factors (SIFs) and flexibility factor (k’s) for the discontinuity at hand. There are however well-known limitations in the accuracy of these formulas which, depending on the situation, can lead to either conservative or optimistic results. Within Appendix D these inadequacies are acknowledged and if available the engineer is advised by the code to use “more applicable data”. Based on results of the latest analysis, research, and testing conducted for the ASME committee, largely undertaken by our technology partner Paulin Research Group, this “more applicable data” is now widely available as ASME document STP-PT-073. This improved data is especially relevant for systems with large D/T, with sensitive or rotating equipment, in cyclic operation and with short or stiff thick-walled piping, or where the solution is dependent on the SIF for a small bore connection. Application of these newer values can result in significant lower stress which can result in more economical design. For some more critical situations it can even result in more realistic stress values which are higher, which allows for a reduction of risk for failure in such cases. The relationships, whilst improving the accuracy of the analysis, are not trivial to apply. FEATools is a software package developed by Paulin Research Group which couples with CAESAR II to incorporate the “more relevant data” from STP-PT-073. The model is built in CAESAR II, imported into FEATools where the SIFs and k’s are updated and then exported and solved in CAESAR II. In this 2 day training course, which is new for 2016, the participants will learn how to apply this most up-to-date knowledge on SIFs and flexibility factors including backgrounds, validity and uncertainties. The software FEA Tools and the interaction with CAESAR II will be treated in detail. This will be done in a mix of lectures and worked examples which allow the participant to become familiar with the differences in accuracy due to the “more applicable data” statement of the ASME B31.3 Appendix D code. The course will also explain the new SIF and flexibility calculation procedures and their deviation from those found in B31.3 Appendix D.