Hurricanes
Mechanical
I recently managed to get hold of a copy of 'Design of Piping Systems' by the M W Kellogg company. In the chapter relating to strength of materials, it discusses yield conditions, detailing both the Tresca and the von Mises yield conditions.
Where it got interesting for me was the discussion of low carbon steels which typically have an upper and a lower yield point. As the limit stress is based on the lower yield point, it is the stress required for the Luders bands to widen.
Only the shear stress acting in the plane of the Luders bands can cause them to widen, and as the intermediate principal stress is perpendicular to the bands it must be ineffective. Therefore the yield condition is closer to Tresca than von Mises.
Is this why the ASME codes use Tresca rather than von Mises? My other piping books make no mention of Luders bands, one says Tresca is preferred as it is mathematically simpler compared with von Mises.
Does anyone know of any references which discuss this further?
I have read through previous discussions here on Tresca, Von Mises and Principal stresses, but this doesn't seem to have been mentioned.
Where it got interesting for me was the discussion of low carbon steels which typically have an upper and a lower yield point. As the limit stress is based on the lower yield point, it is the stress required for the Luders bands to widen.
Only the shear stress acting in the plane of the Luders bands can cause them to widen, and as the intermediate principal stress is perpendicular to the bands it must be ineffective. Therefore the yield condition is closer to Tresca than von Mises.
Is this why the ASME codes use Tresca rather than von Mises? My other piping books make no mention of Luders bands, one says Tresca is preferred as it is mathematically simpler compared with von Mises.
Does anyone know of any references which discuss this further?
I have read through previous discussions here on Tresca, Von Mises and Principal stresses, but this doesn't seem to have been mentioned.
