he difference between impact energy and static energy

huangyhg

the difference between impact energy and static energy
if a structure (eg: a tire) been subjected to an impact, and a static force (with a plunger)until it fails,
which failure energy be higher, or will they be same.
( impact force will also be applied using the same plunger to the same position)
if one is different from the other ; why or how ?
since, i belive both required energy to be same...
thanks
sriwardene
if you are saying that in both tests, both the total distance travelled by the "plunger" after initial contact with the "structure", and it's overall displacement, are identical, then the only difference would seem to be the rate of travel of the plunger. but this can have a profound effect. in the case of plastic deformation of metals, for example, the strain rate alone can have a considerable  effect on force. there can also be important inertia effects also, since there is the question of how much of the impact energy is converted into local or bulk kinetic energy of the structure, and how much is converted into strain energy of the structure itself. as an analogy, consider a piece of rope hanging vertically. if you swing a sword at it, horizontally through some fixed distance, the rope will probably be severed, but if you swing it very slowly through the same distance, it will not even be marked. in the case of a tire impact, such effects could obviously be very important.