A SYSTEMS-APPROACH TO THE TORSIONAL VIBRATION OF MULTI-CYLINDER RECIPROCATING-ENGINES AND PUMPS

The systems approach for the vibration analysis of complex systems req uires that the receptances of the sub-systems are available. For the t orsional vibration of rotating systems including reciprocating engines and/or pumps it has been the practice to represent the reciprocating mechanism by a constant rotary inertia. This paper describes the deriv ation of the receptance for such reciprocating mechanisms, which inclu des the effects of non-constant rotary inertia. It is then shown how t he natural frequencies for torsional vibration vary with angular posit ion and how this in turn affects the vibration in the time domain. The significance of tire effects indicated by these simulation techniques is then demonstrated by comparing with results obtained from an exper imental investigation.