SPYDERLK
Super Star Member
- Joined
- Feb 28, 2006
- Messages
- 10,323
- Location
- VA
- Tractor
- JD2010, Kubota3450,2550, Mahindra 7520 w FEL w Skid Steer QC w/Tilt Tatch, & BH, BX1500
There is elastic stretch and plastic stretch. Elastic stretch snaps back - plastic doesnt. All chains, and bolts for that matter, have initial elastic stretch that at some % gives way to yield - plastic stretch. All steel stretches elastically about the same, whether high or low stength. This means all steel has about the same stiffness. The difference comes in after the low stength steel begins to yield - it will no longer return to its original length when relaxed, whereas the hi strength will continue to stretch elastically. Perhaps it will stretch twice as far [taking twice as much force] before begining to yield. Twice the average force for twice the distance means it has 4x the stored energy. This energy surplus remains about the same as the two chains yield. When they break the low stength chain will be relatively well behaved in comparison to the hi. Standard logging chains are only moderate strength so they yield relatively easily and store less energy. Safer, but you pay for it by having to use larger chain to get the same strength. The energy surplus of the equal smaller chain of hi strength steel would then be 2xdistance and 1x force.... Twice the E.IslandTractor said:Are you sure that is correct? I know that marine chain is rated by several parameters and one of them is % stretch before failure. All that energy from pulling with 40hp or whatever your tractor puts out has to be stored somewhere if you are tugging away at a stump. The stump itself must have some of it but a sudden failure in the chain must release a fair amount back towards the source of the energy too (ie tractor).Any physicists, mechanical engineers or material scientists out there?
larry