Recent progress in the plastic methods of structural analysis

The techniques described in Part I of this paper for the calculation of plastic failure loads under proportional loading are further exemplified by indicating solutions for a rectangular building frame, a Vierendeel girder, and a shed-type portal frame. A method for estimating deflections of a frame just as the collapse load is attained is then described, with some indications as to its reliability. More general conditions of loading than proportional loading are next discussed, and generalized load and failure concepts are defined. The theorems and techniques for determining critical shakedown loads under variable, repeated loading are then described and illustrated. The relation of the elastic-plastic shakedown analysis to the much simpler analysis for failure under single load applications is discussed.     

Steady forced vibrations of single mass systems with symmetrical as well as iinsymmetrical non-linear restoring elements

Part of the theory and all the experiments reported on in this paper were condensed into a four-page discussion or addendum to Professor Den Hartog's original paper on “Amplitudes of Non-Harmonic Vibrations” at the time of its presentation at the June Meeting of the A.S.M.E. in Chicago, 1933. Upon the instigation of Professor Den Hartog and the Editor of the Journal of the Franklin Institute, the original discussion has been brought into the present form.