1. Update on workshops 18-19th May 2017
FEA workshop: STFC Daresbury
D. Butler, W. Tizzano
Metal Additive Manufacture Seminar: Manufacturing Technology Centre, Coventry
S. Scott, A. Peach

2. List of presentations (available in engineering design guidelines -> FEA)
FEA ‘Best Practice’ (a 30 year personal perspective)
The FEA assessment and PSE certification project
STFC Best practice survey
ISIS TS1 project: Target design and analysis
Thermal analysis for Space: Finite Difference vs Finite Element
Simulations of laser engineered surface structures for the LHC high-luminosity upgrade
Steel structures for compliance with Eurocode 3
Simulation of a bolted frame for the ISIS TS1 project
Parametric optimisation for the ISIS target station one project cryogenic moderators
Thermal Analysis of the SKA electronics cabinets using Ansys Icepak/Fluent CFD
Simulation for Additive Manufacturing
Electromagnetic Finite Element Simulations at ISIS

3. FEA Good practise – Barry Fell
Dedicated FEA / CFD machine
HPC (multi-core licence) with lots (128 GB) of RAM
Simple problems can solve quickly
Large problems (2-3 days) don’t monopolise users workstation
Real world validation
Aim to perform some validation either bench top or full scale
Model simplification
Physics often uncertain so ok accept large uncertainties
Library of validated Materials

4. FEA Good practise – Barry Fell
Library of hand calculations
Mathcad documents / template calculations
Well documented
Centrally accessible and locatable
Reporting policy
Reports generated for any and all analyses / modelling
Aim to avoid searching for …analysis_1…. analysis_n and trying to figure out what it was months after the event
Standard FEA / CFD template
Initial modelling / hand calcs
Verification
Qualifications / assumptions / simplifications
Conclusions
Make it available / accessible!

5. FEA Good practise – Barry Fell
e.g. Roark and Young in Mathcad worksheets

6. NAFAMS
"To promote the safe and reliable use of finite element and related technology"
Simulation is a tool for engineers, should not be specialists operating in isolation
In the past it was a specialist field due to the computing requirements
Assist with CPD and offer a certification of competency in FEA / CFD
Entry level
Standard level
Advanced level

7. NAFAMS Competencies Professional Simulation Engineer (PSE) skills
Assess competency of simulation and modelling
Non-package specific
26 areas of competency

8. NAFAMS – Why? External validation of simulation competency
Application for a level of competency in selected areas
Does not need to be all 26x
Interview
Certification awarded at appropriate level
Internationally recognised
PSE competency tracker a tool for learning
Competency statements
E.g. MESMkn20 - Define Tresca and von Mises Stress for a 3D stress state
Resource references
E.g. MESMref20 – Pressure Vessels Design and Practice. S Chattopadhyay, CRC Press, ISBN Chapter 3.2

9. NAFAMS at STFC STFC trialled with 3x people
Plan to roll out to rest of STFC engineering
Advanced certification can mentor students
Positive experience reported

10. ISIS TS1 target design and analysis
Redesign TS1 target (and other components) to improve neutronic output, without compromising current reliability
Good example of what 30 years of design and simulation developments can achieve
Heavy water filled vessel for cooling tungsten plates (spallation source)
CFD of cooling – 6 m/s water flow ~ 23,000 m/m2 K
FEA of vessel and optimisation of front window – maximise neutron beam
Mass of material (kg)
Current TS1
TS1 Project
Reduction
Stainless Steel
73.8
8.1
89.0%
Tantalum
32.7
6.9
79.0%
Tungsten
47.3
46.0
2.8%
Total
153.8
61.0
60.3%

11. ISIS TS1 target design and analysis – PD5500
Had to deviate from standard code for their vessel
PD5500 ‘Design by Analysis’ section gives guidance on using ANSYS results, but is not very specific and open to interpretation. In general:
Calculate design strength ‘f’ (minimum of 2/3 yield strength or 2/5 UTS)
Separate stress results into categories (primary membrane, primary bending, secondary)
ANSYS linearised stress results at locations of interest
Apply different limits depending on the location and type of stress:
Location Type
Stress Category
Membrane
Bending
Membrane + Bending
Total Including Thermal
General f
1.5f 3f
Discontinuity
Concentration
N/A
Note: Limits apply to stress intensity (Tresca criterion)

12. Conclusions
Single, high performance dedicated FEA machine offers STFC benefits
Standardised FEA reports including hand calculation
Standard templates for standard calculations
NAFEMS certification
Validation of FEA skills
Not package specific so differs from Ansys training which teaches how to use Ansys not necessarily the theory of FEA