About Roark's book: stress and strain
About Roark's book: stress and strain
(OP)
Being European, I'd like to know whether it would be helpful getting me the "Roark's formulas for stress and strain" book.
Are the formulas in Metric or Imperial units?
No point in getting me a book full of inches, psi and lbs, as I do not come across these units when I work.
Anyone could confirm this?
Many thanks...
Are the formulas in Metric or Imperial units?
No point in getting me a book full of inches, psi and lbs, as I do not come across these units when I work.
Anyone could confirm this?
Many thanks...





RE: About Roark's book: stress and strain
RE: About Roark's book: stress and strain
RE: About Roark's book: stress and strain
http://
From looking through it I see there seem many more USCU "examples" than SI examples, however all the formula's are presented in a standard engineering manner that is not unit-specific.
Re: PC's comment. FWIW I have lived my whole life in the US. I can/have worked most simple type problems in both systems. As the complexity of problem increases, I have found it is invariably easier to convert input quantities to SI (even though given in USCU), perform the entire calculation using SI units, and convert the output quantities back to USCU. By "easier", I mean fewer unit conversions requires, less thought and book-keeping required to tend to unit-related matters. Things like numerical differentiation and numerical integration flow naturally when SI units are used without extra consideration of factors related to units. My stuff usually doesn't include things involving empircal correlation relationships.
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RE: About Roark's book: stress and strain
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RE: About Roark's book: stress and strain
While they're entered with US units, Mathcad does unit conversions on the fly, so you simply enter the correct values and SI units, and the equations will still work correctly.
TTFN
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RE: About Roark's book: stress and strain
RE: About Roark's book: stress and strain
TTFN
FAQ731-376: Eng-Tips.com Forum Policies
RE: About Roark's book: stress and strain
TTFN
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RE: About Roark's book: stress and strain
RE: About Roark's book: stress and strain
David
RE: About Roark's book: stress and strain
In Mathcad, that's completely unnecessary:
> The equations are in natural form, so they're completely readable as recognizable equations like those in the text
> In most cases, an entry requiring, say, psi, can simply be entered with Pa, and that's ALL you have to do.
Obviously, much of this requires that the equations be properly entered and dimensioned in the first place, but the effort is not that different than validating the equation as used in any other calculation approach. The difference is that if done correctly, you ought not need to do that ever again.
One option, to get your feet wet, is to buy a copy of Studyworks for about $10: h
While it's quite outdated, ca. 2002, this stripped-down version of Mathcad is still quite useful for numerical calculations, and provides a human-readable input/output for archival and documentation purposes. Note that Studyworks does not include programming and some higher-order math functionality, and only a limited symbolic capability.
TTFN
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RE: About Roark's book: stress and strain
RE: About Roark's book: stress and strain
The preface even states "The sixth edition uses the International System of Units (SI) in presenting many of the example problems. Tabulated coefficients were in dimensionless form before and remain unchanged. Design formulas drawn from works published in the past remain in the system of units originally published or quoted."
Its a useful reference so you should get a copy.
RE: About Roark's book: stress and strain
RE: About Roark's book: stress and strain
A kgf is not an SI unit!
(Neither for that matter is the cm.)
Doug Jenkins
Interactive Design Services
http://newtonexcelbach.wordpress.com/
RE: About Roark's book: stress and strain
I work with metric a lot. I work with US Traditional Units a lot. Jumping back and forth is pretty easy (especially since I started imbedding the required units within empirical equations in MathCAD--I love that I can input "mm" and then MathCAD divides it by "inches" to get a unitless number that is consistent with the constants).
I think that the important thing with units is that you have clear communication. If you do that then microFarads/fortnight is almost reasonable.
David
RE: About Roark's book: stress and strain
You are correct about kgs, but incorrect about cm.
http://
http://physics.nist.gov/Pubs/SP811/contents.html
RE: About Roark's book: stress and strain
But shouldn't it be furlongs/fortnight? Both were units added in Mathcad version14.
TTFN
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RE: About Roark's book: stress and strain
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RE: About Roark's book: stress and strain
I just want to communicate, don't care what is in SI and what isn't, don't care who uses what units that are excluded from the SI protocols, mostly just don't care.
David
RE: About Roark's book: stress and strain
You should read the BIPM brochure, specifically Chapter 3, "Decimal multiples and submultiples of SI units" Note also, Table 6 in Chapter 4.1, where non-SI units are defined in SI units, and cm is used as a "SI unit."
The "Bureau" is the final arbiter of all things SI, if they say cm is a part of SI, then it is.
TTFN
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RE: About Roark's book: stress and strain
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RE: About Roark's book: stress and strain
No worries...
Like Dave, the tool I use is indifferent to unit systems.
The only downside, as it were, is that I forget what most of the conversion factors are.
TTFN
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RE: About Roark's book: stress and strain
It seems I was. Nonetheless it is normal practice (at least in the English speaking world) to use multiples of 1000 of the base units, which does make life much easier.
Doug Jenkins
Interactive Design Services
http://newtonexcelbach.wordpress.com/