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Is mill steel sections isotropic or anisotropic?
- Thread starter Ron247
- Start date
It depends on how it is fabricated. Forgings are generally isotropic, rolled products are generally anisotropic (this would include HSS, tube, or other structural sections formed from rolled sheet and seam welded).
In sheet metal forming, particularly deep drawing, the r value of the base material is very important, because you're deliberately operating in the plastic strain regime. For structural components where you're staying out of plastic strain as much as possible, speaking generally, the difference in r value between various orientations is small enough relative to loads and load factors that it is disregarded most of the time. Anything that is a high strength alloy, is hot rolled, or both, will have an r value closer to 1 than cold rolled/low alloy products; this also contributes to disregarding the anisotropy for structural applications since a lot of structural shapes are hot rolled.
'Treat structural steel as if its properties are isotropic' reads to me as one of those college generalizations you learn because in the real world, as a structural engineer, it's something you only have to actually concern yourself with in edge cases, so it's disregarded in bachelor-level college classes as an unnecessary complication to structural calculations.
Whether or not you can disregard the anisotropy in whatever product you're using requires you to make a decision based on your loads/margins, what exact product you are using and its r value, etc.
In sheet metal forming, particularly deep drawing, the r value of the base material is very important, because you're deliberately operating in the plastic strain regime. For structural components where you're staying out of plastic strain as much as possible, speaking generally, the difference in r value between various orientations is small enough relative to loads and load factors that it is disregarded most of the time. Anything that is a high strength alloy, is hot rolled, or both, will have an r value closer to 1 than cold rolled/low alloy products; this also contributes to disregarding the anisotropy for structural applications since a lot of structural shapes are hot rolled.
'Treat structural steel as if its properties are isotropic' reads to me as one of those college generalizations you learn because in the real world, as a structural engineer, it's something you only have to actually concern yourself with in edge cases, so it's disregarded in bachelor-level college classes as an unnecessary complication to structural calculations.
Whether or not you can disregard the anisotropy in whatever product you're using requires you to make a decision based on your loads/margins, what exact product you are using and its r value, etc.
- Thread starter
- #4
SWComposites
Aerospace
at first order steel is isotropic, which is good enough for most design purposes.
when one looks very closely, with very good test methods, steel like almost all metals is anisotropic in stiffness and strength.
when one looks very closely, with very good test methods, steel like almost all metals is anisotropic in stiffness and strength.
- Thread starter
- #6
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