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The formulation of the dynamic equations of motion proposed by Udwadia-Kalaba is discussed from the point of view of numerical efficiency. Since this formulation requires the computation of a pseudoinverse matrix, it has investigated the influence of the method of pseudoinverse computation on the dynamic simulation of an overconstrained linkage. Finally, it has been proposed that a new dynamic equation which explicitly computes accelerations also in the case of mathematical models with rank deficient Jacobian and mass matrices. DOI: 10.1061/(ASCE)0893-1321 (2009)22:4(365) CE Database subject headings: Matrix methods; Computation; Simulation; Aerospace engineering.

The analysis of mechanical efficiency constitutes an important phase in the design analysis of gear drives. The objective of this investigation has been the development of a general algorithm for the determination of efficiency in split-power spur-gear trains. The model includes meshing losses only; for a more realistic estimation other sources can be considered separately. The systematic nature of the formulation, based on the dual correspondence between the kinematic structure of the gear drive and a labelled graph, allows a ready coding of the efficiency analysis in a general computer program. The numerical results are in line with those given by other authors using different methodologies.

It is well known that the circulating power in gear trains can be many times greater than the input power. Such circumstances require that in the design of split-power gear drives, a preliminary power-flow analysis be carried out. In this investigation a systematic method for the power-flow and static-force analysis of spur-gear drives is presented. The manner in which the procedure is applied has some similarities with an algorithm for kinematic analysis previously suggested by one of the authors. Following a brief review of previous work, the theoretical bases of the new methodology of analysis are discussed and numerical examples developed.

Byline: E. Pennestri, P.P. Valentini, L. Vita This paper deals with numerical models developed in order to simulate the vibrational and postural comfort of car occupants. The proposed models have been based on different mathematical approaches: the first is a multibody dynamics model and the second is a finite elements model. Both models have been validated by means of static and dynamic experimental tests on vehicles using appropriate test rigs. The authors focus on the advantages and disadvantages of each model in order to have useful information about which approach has to be used to predict objectively the comfort of driver and passengers.

Byline: M.E. Biancolini, C. Brutti, E. Pennestri, P.P. Valentini Cardan and double Cardan homokinetic joints have a wide spectrum of application in vehicle design. This paper proposes mathematical models for mechanical efficiency and torque analysis. The problem of fatigue analysis has been adressed. In particular, it has been investigated the influence of working parameters on the life expectancy of the joint. Design charts have been prepared for a ready use of the proposed models.