PSI - Issue 33

Aprianur Fajri et al. / Procedia Structural Integrity 33 (2021) 11–18 Fajri et al. / Structural Integrity Procedia 00 (2019) 000–000

13 3

used, namely: Goodman in Eq. (3), Soderberg in Eq. (4), Gerber in Eq. (5), and ASME Elliptical in Eq. (6) (Venkatasudhahar et al., 2014)

Fig. 1. Different alternating stress condition : (a) zero mean; (b) ratio

S

S

alternating

(3)

1





mean

S

S

endurance

ultimate

S

S

(4)

alternating

1

mean S   yield

S

endurance

2

S

  

  

S

alternating

(5)

1





mean

S

S

endurance

ultimate

2

2

 

   

S

  



S S

alternating

1

(6)

    



mean

S

endurance

yield

The Fatigue life can be calculated based on the rules of the Palmgren-Miner linear damage hypothesis in Eq. (7). (7) Where, � is the number of stress range cycles due to different factual stresses in the � �� � � � �� Then � is the number of cycles resulting in the failure of the constant alternating stress � (derived from the S-N Curve), failure occurs when cumulative damage ( D ) is greater than 1 3. Test References Fatigue analysis on notched cantilever beams using FEM was conducted by Köksal et al. (2013). The material used in this study is a structural steel with mechanical properties shown in Table 1 and fatigue data test in Fig. 2. The dimensions of the geometry model are 1000 x 100 x 75 mm, with a notch angle of 90 o and a depth of 25 mm (see illustration in Fig. 3). This cantilever beam is designed with a minimum life of 10 6 cycles. 1 N  k i i i n D  

Table 1. Mechanical properties of structural steel. Modulus elasticity (GPa)

Poisson’s ratio

Yield strength (MPa)

Ultimate tensile strength (MPa)

200

0.3

250

460