Comment on "Flutter of a Panel Supported on an Elastic Foundation"

Comment on "Natural Frequencies of a Cantilever with Slender Tip Mass"

“…1 will lead to the same results as those indicated in Ref. 2, the two procedures being merely alternative ways of arriving at the same answer. This is not the case.…”

“…2 relating the curve of A vs g r for a panel unrestrained by an elastic foundation to the corresponding curve for a panel restrained by an elastic foundation of stiffness, K = K } , is unique and one to one for corresponding points on the curves. The transformation depends on a knowledge not only of g r , the damping coefficient, and A, the flutter speed parameter, but also of W F , the flutter frequency.…”

“…The special circumstances, however, make it possible to carry out the perturbation analysis directly and simply by differentiation of the exact characteristic equation for frequency rather than having to use the more general and somewhat more laborious analysis of RayleighV classical perturbation theory. 2 For the case 0 = 0, the characteristic frequency equation reduces to…”

“…Unfortunately, their formulas for the perturbation method appear to be in error, and this, in turn, gives rise to large errors in their numerical results for the perturbation method in the case 13 = 0, leading finally to their incorrect conclusion that the perturbation method fails in some way for 0 = 0. The first-order errors in the numerical The usual perturbation expansion for the beam frequency parameter \ n is (2) X is given by where co is the vibration frequency and El is the bending stiffness of the uniform beam.…”