PSI - Issue 17

C P Okeke et al. / Procedia Structural Integrity 17 (2019) 596–601

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C P Okeke et al / Structural Integrity Procedia 00 (2019) 000 – 000

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4. Conclusions

The dynamic response shows nonlinearity, as expected of polymers. The peak frequency decreases with increasing input loading, the rate of decrease is significant up to 30m/s 2 input loading before it starts to flatten out. The transmissibility also shows similar behavior to the peak frequency. The obtained fatigue life curve shows significant scatter at 40% fatigue load level. The assessed fracture surface micrograph of the fatigued specimens at three load levels shows surface tear at 80% and 60% load levels. With high level of nonlinearity in the dynamic behaviour, the significant variations in the fatigue life and the sensitive to high stress loading, designing with vacuum cast polyurethane requires extra care. Although the vacuum cast PU can save cost and time for ultra low volume production, however, the automotive lamps made of conventional injection moulding technique are much more robust than that of vacuum cast PU.

Acknowledgements

This research has been funded by Wipac Ltd. The authors would like to acknowledge Ogle Models for providing the Vacuum cast polyurethane test specimens.

References

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