They do store whatever energy is imparted on them. It is how they release (rate
of change) that energy that makes the big difference
Chains do NOT stretch 'as' much as plastic straps, but chains DO stretch and store
energy. Why the links are oval and not round. Also, the fragmentation is dependent
on the alloy/hardness of the chain links
I've seen chains snap and fragment during acceptance certification testing of
our equipment for cranes. Big cranes. Also saw how some of those fragments
embedded themselves in metal cabinets. Been decades since a designer and now
see plastic straps where chains were the norm. Cable was also used, but not
as often as their maintenance schedules required change often....again, wonder
how plastic straps are now allowed.
Do know that for public road trucking of metal (sheetmetal, plate, etc) does NOT
allow plastic straps on bare metal. Accident would have the plastic straps cut
in an instant
Speculation on my part of this hitch system. As I do NOT know the properties of
the plastic compression springs. Therefore their energy release characteristics
Nor their compression characteristics...will they become un-compressible within
some compression distance like a coiled steel spring?