| In my first semester of training in Urbana I received a mental body blow when Professor Shedd quoted Cross who had said that in structural design a calculated under- or over-estimate of 15 % is almost always of trivial concern.
Had I wasted my years learning exact analysis?
Eventually, I fell in line with Professor Shedd and kept repeating Cross’s quote in the classroom when I started teaching.
On 15 January 2008, I received a counterblow when I read a forensic report, from an organization I respect, that concluded with the statement, “A 15% overstress is significant.”
Have I been misguiding engineering students for over half a century?
I intend to talk about the relationship of analysis to design of
structures for lateral loading, explosion, and high-speed impact but
the main reason for my talk will be to think about the significance
of 15% overstress in design analyses with the hope that I shall be
set straight by the audience.
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