On the Influence of Ultimate Number of Cycles on Lifetime Prediction for Compression Springs Manufactured from VDSiCr Class Spring Wire.

Max Benedikt Geilen,Matthias Oechsner,Marcus Klein

doi:10.3390/ma13143222

Max Benedikt Geilen, Matthias Oechsner + Show 1 more

Open Access

https://doi.org/10.3390/ma13143222

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Abstract

For the generation of fatigue curves by means of fatigue tests, an ultimate number of cycles must be chosen. This ultimate number of cycles also limits the permissible range of the fatigue curve for the design of components. This introduces extremely high costs for testing components that are to be used in the Very High Cycle Fatigue regime. In this paper, we examine the influence of the ultimate number of cycles of fatigue tests on lifetime prediction for compression springs manufactured from VDSiCr class spring wire. For this purpose, we propose a new kind of experiment, the Artificial Censoring Experiment (ACE). We show that ACEs may be used to permissibly extrapolate the results of fatigue tests on compression springs by ensuring that a batch-specific minimum ultimate number of cycles has been exceeded in testing. If the minimum ultimate number of cycles has not been exceeded, extrapolation is inadmissible. Extrapolated results may be highly non-conservative, especially for models assuming a pronounced fatigue limit.

Highlights

A standard for the minimum lifetime of compression springs under cyclic loading is given in EN 13906-1 [1]
We show that Artificial Censoring Experiment (ACE) may be used to permissibly extrapolate the results of fatigue tests on compression springs by ensuring that a batch-specific minimum ultimate number of cycles has been exceeded in testing
Several datasets on the fatigue behavior of compression springs manufactured from VDSiCr are available

Summary

Introduction

A standard for the minimum lifetime of compression springs under cyclic loading is given in EN 13906-1 [1]. This standard is a great help for design engineers because it allows a safe design at a reasonable design cost and a reasonable utilization of the materials used. The potential for lightweight design is not fully exploited. University of Darmstadt and the Technical University of Ilmenau. Once published, it will allow designing for higher numbers of cycles as well as a better exploitation of lightweight potential

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Conclusion