The position of the neutral axis (N.A.) for fully plastic unsymmetrical sections is given by:

area of section above or below N.A. = total area of cross-section

Deflections of partially plastic beams are calculated on the basis of the elastic areas only. In plastic limit or ultimate collapse load procedures the normal elastic safety factor is replaced by a load factor as follows:

j collapse load allowable working load

For solid shafts, radius R, strained up to and beyond the elastic limit in shear, i.e. for plastic torsion, the torques which can be transmitted at each stage are

maximum elastic torque te =

TTTy partially plastic torque TPP = —— [AR - ] (yielding to radius R\)

0 0

Post a comment