Comparison of different methods to estimate parameters of the Weibull distribution for fatigue strength

The normal distribution is widely used in fatigue calculations of the strength or life of construction components. However, it is not recommended to use for calculations for probability equal to or less than 5%, which was written in standard ASTM E-739-10. For this purpose, Weibull distribution is proposed by standard ISO-12107. Unfortunately, this distribution has many methods to estimate parameters. Four methods were presented. It is a graphical method, method of moments, weighted moments method and maximum likelihood method. The worst results have obtained through a graphical method. Other methods have similar results. The purpose of the paper is to present and compare methods for estimating Weibull distribution for 3 parameters for fatigue strength. An example of such estimated distributions is for fatigue life for 760 MPa stress amplitude for steel SUJ2 for torsion load.