PSI - Issue 28

Jesús Toribio et al. / Procedia Structural Integrity 28 (2020) 2386–2389 Jesús Toribio et al. / Procedia Structural Integrity 00 (2020) 000–000

2388

3

-1200 -800 -400 0 400 800 1200

 z (MPa)

0 0.5 1 1.5 2 2.5 3 3.5

r (mm)

Fig. 2. Radial distribution of axial residual stress on the wire.

Table 1. Maximum stress in absolute value (  max ) and normalized with material yield strength (  =  max /  Y ) defining the cyclic loading schemes. Cyclic Loading Schemes I II III  max (MPa) 1200 1300 1500  =  max /  Y 0.90 1.00 1.15

3. Influence of the maximum cyclic loading To reveal the effects of the fatigue (cyclic) loading on the residual stress distribution in the prestressing steel wire, the radial distributions of axial effective stress after fatigue loading (difference between the axial stress and the applied in-service stress) are compared in Fig. 3 with the residual stress distribution just after wire drawing (Fig. 2).

-1200 -800 -400 0 400 800 1200

Residual   

 z (MPa)

0 0.5 1 1.5 2 2.5 3 3.5

r (mm)

Fig. 3. Radial distribution of the axial effective stress after fatigue loading compared with the axial residual stress after cold drawing (cf. Fig. 2).

A redistribution of the residual stress profile with stress reductions at all points appears after cyclic loading. The stress reduction increases with the maximum cyclic stress applied to the wire (Fig. 3). It is as high as 48% for loading under the material yield strength (Loading I,  = 0.90). The reduction is slightly higher for fatigue loadings with a maximum stress reaching the material yield strength (Loading II,  = 1.00). Fatigue loading with a maximum stress overcoming the material yield strength (Loading III,  = 1.15) is required for the highest stress reductions.