That was an interesting report Jymil.
Shame that Eagle got caught-out with a loaned engine.
For our engineering brethren .. There are some good illustrations in the report linked by Jymil (above) and in one illustration (at the top of page 22 and reproduced below) it says:
"The bevel pinion of the outer pinion gearshaft assembly exhibited pronounced damage and plastic deformation."
I've not come across this term 'plastic deformation' before ( .. I've lived a sheltered life you see
) but which I now understand is a standard engineering expression. One definition I have read says:
"Under tensile stress plastic deformation is characterized by a strain hardening region and a necking region and finally, fracture (also called rupture). During strain hardening the material becomes stronger through the movement of atomic dislocations. The necking phase is indicated by a reduction in cross-sectional area of the specimen. Necking begins after the ultimate strength is reached. During necking, the material can no longer withstand the maximum stress and the strain in the specimen rapidly increases. Plastic deformation ends with the fracture of the material."
Could anyone provide me with a slightly more 'layman' style explanation? I've also read that before a metal can suffer 'plastic deformation' is must first have undergone 'elastic deformation'?
What I understand (from what I've read) is that a material (in this case metal) becomes deformed under stress (and which must of course have quite a bit to do with heat) and that this deformation reaches a point beyond which 'recovery' is no longer possible, ie. the deformation becomes permanent and which (I am also guessing) is the difference between 'elastic' and 'plastic' deformation?