This investigation concerns with the mechanical efficiency of Cardan joints. The model includes also the effects due to manufacturing and mounting errors and the influence of rotation speed on the efficiency. The joint has been modeled as an RCCC spatial linkage and the full dynamic analysis performed by means of dual vectors algebra.

Some didactic issues associated with the computation of degrees-of-freedom (d.o.f.) are herein discussed. In particular the paper reports different definitions and methodologies of computation of this important parameter. It is also proposed an analytical approach to the d.o.f. computation of planar figures subjected to unilateral constraints. Mechanisms with variable kinematic structure are included in the present analysis. Some ambiguities in the d.o.f. definition are pointed out.

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Fourier analysis is used as a framework in which to obtain spectral estimates for nonstationary discrete time signals. Analysis of the auto-power spectrum and the cross-power spectrum makes it possible to distinguish between false alarms and real risk situations and, in the latter case, to determine the propagation of any possible damage in its earliest phases. This analysis then allows corrective actions to be taken, such as parts replacement, in order to limit damage and contamination of component parts in fatigue tests and thus shorten machine stoppage times.

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Professor Bruno Piombo has shown us that the passion for the research and for teaching is a never-ending gift.Abstract. A double-ended cantilever beam as a distributed parameter dynamic vibration absorber has been applied to a singledegree-of-freedom system subjected to harmonic forces.In this investigation, the beam has been analyzed under the well known model of Timoshenko and the computation of best parameters is based on the Chebyshev's optimality criterion. This is somewhat novel in the field since:-the design of cantilever beams as dynamic vibration absorbers is usually made under the hypotheses of the Euler-Bernoulli theory; -it is the first time that the Chebyshev's criterion is applied to the design of a double-ended cantilever beam used as a dynamic vibration absorber.For a ready use of the results herein presented, design charts allow a quick choice of optimal parameters such as tuning ratio and mass ratio.