Strain Gauging - was Re: [PSUBS-MAILIST] Is ABS Reliable?

["Sean T. Stevenson" <cast55@telus.net>]

Incidentally, if anyone here is involved in an ABS certified project, I would 
like to offer my expertise in this area.  I have extensive experience with 
strain gauging, finite element modelling and calibrating computer models 
against field stress measurements to predict stresses in ungauged locations, 
and estimate fatigue life of structures and/or specific weld details within a 
structure.  I provide these services to the mining industry - typically on 
haul trucks, electric cable shovels and walking draglines, but the principles 
are equally applicable to subs.  I can, of course, offer a full consulting 
service at my professional rate where required, but I'm happy to provide a 
bit of guidance to the DIY'er with regard to strain gauging - it's not rocket 
surgery.

-Sean


On September 5, 2006 19:33:23 Adam wrote:
> The ABS is reliable.
>
> I discovered a couple mistakes a few years back, but they were soon
> corrected and the corrections were released in the ABS corrigenda. These
> mistakes were actually typos. I found the mistakes through unit analysis,
> in other words, by making sure all the units worked out.
>
> The ABS will not certify your design based purely on the equations they
> provide. Strain gauging and FEA is typically needed because some shapes are
> not easily described by hand written equations. And, at the same time, they
> also require a hydrostatic test, this test is usually done in conjunction
> with a strain gauging and/or with something that monitors the change in
> volume as pressure increases.
>
> So, I believe the ABS is reliable but in the business of making money and
> at least they are covering their butt. It is still up to you to cover
> yours.
>
> Regards,
>
> Adam Lawrence



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