Sir,

Moreover, disc springs are usually stiff springs, but can be made soft by using multiple springs in series in stacks, each facing opposite of the above ones.
But, the real positive point may be cost & ease of manufacturing. We can't rule out the possibility of rugged, cheap springs made of disc springs before hearing from vendors & users.
So far as non-linearity is concerned, we can linearize near the zone of application & use linear spring model, isn't it ? Moreover, 25% variability limit may be unnecessary, when we use the spring stiffness in analysis & the governing state code does not insist so.

Chinese could be creative because they could not read English & study industry standards to limit their imagination! Moreover, eastern thinking encourages multiple views, evidences / contradictory evidences instead of rigid recommendation as the basis for any decision.

I have seen extremely complicated pulverized coal power plants of 25 MW size with 5/6 feed water heaters, which may look funny, but can create a lot of operators with excellent experience for running bigger sized plants of similar complexity.

Our biggest drawback is in following the past blindly. If our past generations were like us, perhaps they could not make such great progress!

regards,
sam


please see below:
http://www.pipingtech.com/news/arc_pw_2003/engps2003_04.htm

for similar sway brace application with 715 kg/mm stiffness