Reciprocating internal combustion engines; Performances; Part 5 : Torsional vibrations

This document establishes specific requirements and methodologies for evaluating torsional vibrations within reciprocating internal combustion engines. It addresses the mechanical oscillations that occur in the rotating assembly, which can lead to fatigue failures or operational instability if not properly managed. The text outlines procedures for determining natural frequencies, damping characteristics, and the critical speed ranges of engine shafts and associated components. Detailed guidelines are provided for the setup of test rigs, the selection of measurement instruments, and the analysis of vibrational data obtained during performance testing. It serves as a reference for engineers designing engines or conducting diagnostic assessments to ensure mechanical integrity under dynamic loading conditions. The scope covers various engine configurations and operating states relevant to the transmission of torsional forces through the drivetrain. By defining standardized approaches for these evaluations, the document aids in the consistency of results across different testing facilities and promotes the safe and efficient operation of prime movers and marine propulsion systems. It focuses exclusively on the technical aspects of vibration analysis rather than general engine performance metrics.