Computational Engineering / module 13
Validation, verification and model assurance
Two different questions that get the same word. Predicting before analysing, the three-stage check, and a record somebody else can review.
What you will understand
- State the difference between validation and verification, and give an example of failing each
- Predict a result before running the analysis, and say why the order matters
- Apply the three-stage check: look and think, check another way, check independently
- Choose a simplification that gives an independent estimate
- Complete a model record that a reviewer can actually use
- Recognise when the software itself is invalid for the problem
Lessons
Two different questions
Validation and verification, separated properly — and why a model that passes one can fail the other completely.
Predict before you analyse
Why the estimate has to come first, and how to make one for a structure that has no formula.
The three-stage check
Look and think; check another way; check independently. In that order, because they cost different amounts and catch different things.
The model record
What has to be written down for a model to be reviewable, and why the exclusions matter as much as the inclusions.
Module summary
- Validation asks whether this is the right model; verification asks whether it was built right
- A model can pass verification perfectly and be a model of the wrong structure
- Predict before you analyse, or you have no independent statement to compare against
- Stage 1 is qualitative and it is where most faults are found
- Stage 2 must use a different route, not the same route done twice
- Stage 3 is another person, another model, or another package
- An assumption not written down cannot be reviewed
- The commonest software failure is a capability the user assumed and the software never claimed
Teaching basis and review status
These are educational models and exercises. Check their assumptions before using the results. The full technical content and every diagram have not yet been independently verified.
Concrete and steel calculations retain their stated first-generation Eurocode teaching basis. Use the standards and amendments specified for your project; do not mix generations without an appropriate design basis.
Read the lesson register and outstanding review notesCheck your understanding
Check yourself
A model of a floor is analysed, and the engineer then hand-calculates the midspan moment and finds it agrees within 3 %. What has this established?
Practice
A 10 m beam carries 30 kN/m. A model reports end moments of 250 kN·m and a midspan moment of 125 kN·m. Compute the free moment wL²/8 in kN·m, and say whether the model is self-consistent.
Practice
A frame's beams are 8 m and carry 24 kN/m. If the columns were infinitely stiff, what end moment would the beams carry, in kN·m? (Fully fixed ends give wL²/12.)