Faculty of Engineering. Optimisation: Getting More and Better for Less. Inaugural Lecture by Vassili Toropov Professor of Aerospace and Structural Engineering School of Civil Engineering School of Mechanical Engineering. Why do we call it that way?.
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by Vassili Toropov
Professor of Aerospace and Structural Engineering
School of Civil Engineering
School of Mechanical Engineering
Opis: Roman goddess of abundance and fertility.
“Opis is said to be the wife of Saturn. By her the Gods designated the earth, because the earth distributes all goods to the human gender“. Festus
Meanings of the word: "riches, goods, abundance, gifts, munificence, plenty".
The word optimus - the best - was derived from her name.
A formal mathematical optimization problem: to find components of the vectorxof design variables:
whereF(x)is the objective function,gj(x)are the constraint functions, the last set of inequality conditions defines the side constraints.
Answer: 1010 seconds
= 317 years
MATHEMATICAL OPTIMIZATION PROBLEM
A general multi-objective optimization problem
Vilfredo Pareto (1848-1923)
Example. You are a looking for a plumber in the Yellow Pages and want the job done both quickly and cheaply.
You consider a particular plumber, do your research and see that no other can do the job cheaper as well as come sooner.
It means that this particular plumber is Pareto optimal with respect to the cost and waiting time.
Conclusion: don’t put up with D!
Don’t confuse optimisation with CATNAP!
Cheapest Available Technology Narrowly Avoiding Prosecution
Human activity only
Natural and human activity
‘A large part of the warming is likely to be attributable to human activities’
Met Office Hadley Centre for Climate Change
Honda F1 goes green!
Honda F1 “Earth Car”
Condensation trails (contrails) Cirrus clouds
EU blueprint for aeronautics research
EU Strategic Research Agenda in Aeronautics
Wright brother’s Flier, FF: 17 December, 1903
Boeing 367-80, FF: 15 July 1954
Airbus A-380, FF: 27 April 2005
Still, things are changing…
Boeing 787, FF: expected in 2007. Composite primary structure
Tupolev 155 (FF 15 April 1988)
Starboard engine: experimental hydrogen–powered NK-88. Hydrogen tank of 17.5 m3 capacity in the aft part of the fuselage.
Liquefied Natural Gas (LNG)-powered Tupolev 156 (FF 18 January 1989)
Starboard engine: experimental LNG–powered NK-88. Tupolev 156 has made over 100 test flights.
Tupolev 205 (210 pass.)
Tupolev 334 (102 pass.)
Tupolev 136 (53 pass.)
Tupolev 330 (36 tonne cargo)
DASA-Tupolev Cryoplane concept based on A-310 (1990-1993)
EADS-Tupolev demonstrator aircraft based on Do-328 (1995-1998)
Alternative fuel advantages
Alternative fuel challenges
X-48, Boeing and NASA Langley Research Center, project cancelled
Boeing X-48B: 21-foot wingspan model UAV built by Cranfield Aerospace. Tests started in February 2007 at Edwards AF Base.
It is very likely that the pressure for a greener aircraft will result in a dramatic change of the aircraft design concept in near(-ish) future
This will be a major challenge for multidisciplinary optimisation!
Possibly, the pressure for a greener aircraft would push the civil aviation development as hard as the stealth technology pushed the development of military aircraft.
If you allow the problem to contain a novel solution then you will get it as a result of optimisation.
I saw the angel in the marble and carved until I set him free.
Michelangelo Buonarrotti (1475-1564)
I choose a block of marble and chop off whatever I don't need.
Auguste Rodin (1840-1917)
Example of topology optimisation
Original design space
Restricted design space
AIRBUS UK RETURN ON INVESTMENT
Note that a truss-like wing rib structure has been obtained that is different from a traditional plate with openings
Let us look at some historic parallels
Later, the truss-like wing rib structures have been mostly replaced by plates with openings and only occasionally used, notably, in Concorde.Topology optimisation produced a truss-like structure again.
Example: composite optimisation
Fibre optimised configuration
Thickness optimized design
Number of plies
A crucial change in the genetic make-up of an ape that lived 2.5 million years ago turned a small-brained, heavy-jawed primate into the direct ancestor of modern humans.
Nature, March 2004
Case StudiesF1 Jaguar Racing Wing
FIA 50kg point loading
Optimise or else…
BESM-6 (1965-1995): 1 Mflop, 32K word RAM, 48 bit word
Is it a blip?
The basic idea is to do the bulk of optimization using the low fidelity model only occasionally calling the high fidelity model
Find optimum blank shape
to minimise waste of material
Hiroshima University and Mazda Corp.
High-fidelity model (Fine mesh)
Time: 150 sec.
Low-fidelity model (Coarse mesh)
Time: 10 sec.
John Koza: Genetic Programming
Example: Tree structure for the expression
Application: Small-scale CHP plant
Application:Optimisation of a shell
W.A. Wright, C.M.E. Holden, Sowerby Research Centre, BAE Systems (1998)
Carren M.E. Holden, Sowerby Research Centre, BAE Systems (1998)
Objective: cost minimisation
Design variables: numbers of steel sections from a catalogue
Constraints: defined by BS 5950
Luna 9 (USSR Space Program)
Mars Pathfinder (NASA/JPL)
Beagle 2 (Beagle 2)
Kistler Booster (Irvin)
Two landing scenarios – Flat bottom and Inclined rock impacts
Baseline design: Flat bottom impact
All requirements are satisfied by the baseline design
Baseline design: Inclined rock impact
Baseline design: deceleration 980g (target <70g)
European Mars Climate Database (EMCD) - general circulation model
45N to 45S latitudes
Mars Global Surveyor dust loading scenario
PDF fit to EMCD model data
NASA/JPL rock size distribution model
Viking 1 & 2, MPF landing sites + Earth analogues
Landing Site rock coverage 20%
Overall rock coverage from orbital thermal imaging
Rock height = 0.5 x diameter
Mars Pathfinder landing site panorama (NASA/JPL)
Pendulum motion + gust reaction under parachute at landing
Assumed to be random with independent normal PDFs
Mean = 0 degs, 3 = 30 degs
Mean = 0 deg/s, 3 = 20 deg/s
Monte Carlo simulation:counting failures…
Another one bites the dust!
ExoMars Lander: LS-DYNA simulation