PSI - Issue 13

H. Soares et al. / Procedia Structural Integrity 13 (2018) 1786–1791 Soares et al. / Structural Integrity Procedia 00 (2018) 000 – 000

1789

4

(5)

( , ) a ssf      = +  eqv a a

( , ) a ssf   is a two variable 5

th order polynomial that represents the SSF damage map for the shear stress space,

where

please see Eq. (6)

(

)

2 (6) where a  represents the loading normal stress component and aims to account for the loading stress level and  represents the ratio of shear stress amplitude to normal stress amplitude and aims to account for the loading type. The variables a to i are the polynomial constants obtained from experiments. These variables vary accordingly to the material type, V. Anes et al. (2014), Vitor Anes et al. (2017). 3 2 3 4 h i        = +  +  +  +  +  +  +  5 ,   a a a a ssf a b c d f g

4. Results and discussion

Fig. (s) 4 and 5 show the SN experimental results for the three loading paths and material with two heat treatments considered (Disc and Rim). The normal and shear stresses of each loading path are presented in separately. Based on these results, and for this material, one can conclude that the heat treatment strongly influences the fatigue strength under uniaxial and multiaxial loading conditions.

Fig. 4. Experimental results. a) Loading cases 1 vs 2, for Disc material, b) Loading cases 1 vs 2, for Rim material.

Fig. 5. Experimental results. a) Loading cases 1 vs 3, for Disc material, b) Loading cases 1 vs 3, for Rim material.