Design Nomographs of Compression Helical Springs for Predetermined Reliability Levels

Abstract

This paper discusses a probabilistic approach for the design of Compression Closely Coiled Helical Springs subjected to periodic axial loading. The classical design procedure results in deterministic geometric parameters with tolerances normally chosen according to standards without due regard to their effects on the mission success as normally expressed by a reliability level. With the proposed design procedure, the engineer can specify nominal mean values for the geometric parameters and their tolerances according to a predetermined reliability level. Design nomographs are presented to help the engineer, in the early stages of design, to choose between many alternatives. Computer algorithms can easily be written to verify the final or optimum design.