20 lines
679 B
Markdown
20 lines
679 B
Markdown
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[[Videos descriptions#Failure theories|video source]]
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The hydrostatic stress is the average stress on all axis, it relates to the stress that want to change the volume like under water pressure (hence hydrostatic), by contrast to the deviatoric stress that act on the shape of the element.
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### For ductile materials :
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The hydrostatic stress has no effect on failure.
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Tresca : easier to apply, more conservative
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*hexagonal prism in stress space*
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von Mises : better agreement with experimental data
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*cylinder in stress space*
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### For brittle materials :
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Compressive strength >>> Tensile strength
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The hydrostatic stress affects failure.
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Coulomb-Mohr : general case of Tresca
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