The details of these changes, chapter by chapter are as follows: No changes have occurred in Chapters 1-9 inclusive, with the exception of Chapter 5 on Self-Excited Vibration which was completely rewritten by a new author (F. F. Ehrich instead of Robert S. Hahn). The new and old versions are both interesting and very much worthwhile, but entirely different in concept. A curious consequence is that tt e venerable names of Routh and Nyquist have disappeared from the Index and hence from the entire book.

Parametric instability of thin, circular cylindrical shells subjected to in-plane longitudinal inertia loading arising from sinusoidal base excitation has been investigated analytically and experimentally. The shell under consideration was rigidly clamped at the base and free at the upper edge. In the applied excitation frequency range, the test specimens exhibited lateral vibrations, at half the driving frequency, with one half longitudinal wave and three full circumferential waves. The linear bending theory used in the analysis was adequate in predicting the incipience of instability, just as in the case of slender rods. Attention has been confined to investigating only the principal instability region, as observed during the experiments. Excellent agreement was obtained between the analytical and experimental results.

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Analytical and experimental investigations have been performed in a study of longitudinal inertia effects upon the parametric response of a column under an axial load P(t) = P0 + P1 cos γt. The analysis has led to stability criteria, imposed on the load and longitudinal inertia parameters, which have shown good agreement with experimental results. A certain degree of scatter between experimental runs has been observed, though agreement within (italics) each run has been very good. The scatter, attributed to small misalignments and departure from axiality of loading, stems from the realignment procedure necessary between each experimental run. To facilitate prediction of parametric response, the analytical stability criteria have been plotted in the form of two bounding surfaces of an instability region in a three-dimensional parameter space. Use of this region permits description of the conditions and responses associated with parametric instability, and allows evaluation of the effects of disturbances.

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