Schwingfeste Dimensionierung von Laufschaufeln für Axialventilatoren

The influence of cast defects on the fatigue behaviour is ascertained taking blades made of an aluminium-silicon alloy in the sand-cast process as an example. For this purpose fatigue tests were carried out on blades, of which the condition and finish were allocated beforehand to different quality categories. Experimental stress analyses were made on the blades in the laboratory and during operation. The values ascertained correspond well with the respective finite element calculations. The lifetime of the blades is examined by the S/N curve, using strain spectra for the blade during operation. The results show that in the present case of application the blade can also be operated safely within the operating range near the resonance.