PSI - Issue 41

Slobodanka Boljanović et al. / Procedia Structural Integrity 41 (2022) 704 – 711 Slobodanka Boljanović et al. / Structural Integrity Procedia 00 (2019) 000 – 000

707

4

b a

M 1.08 0.03 1  

(5)

 0.3 0.44 1.06

M

  

(6)

2

b a

15

b a

b a

  

   

   

  

0.5 0.25

14.8 1

M

  

(7)

3

1.65

b a

  

  

1 1.464

( /

1.0)

Q

a b

 



(8)

where b and t denote crack length in surface direction and thickness of the plate, respectively. Further, in order to evaluate the effect of angle location at the crack front, the corrective factor f   can be employed, as was discussed by Newman and Raju (1984), whereas the finite-width effect of the plate was examined using the corrective factor f w , defined by

4 3 2 1 0.2 9.4 19.4 27.1          w f

(9)

 w b 

t a

    w b

  

0.5

(10)

where w is the width of the plate.

4. Failure analysis using the developed computational design model 4.1. Fatigue resistance estimation

Fatigue performance analysis presented in this Section examines the durability of dog bone plate (Fig. 1a) with elliptical corner crack, made of 2024T3 aluminium alloy. Failure evaluations are performed here in the case of initial crack lengths equal to a 0 = b 0 = 20  m with respect to depth and surface direction, assuming the following values of material parameters, plate width and thickness: C A = 3.2×10 -10 , m A = m B = 2.98, w = 25.4 mm and t = 2.3 mm, respectively. Furthermore, applied cyclic loading is characterized by two different stress ratios ( R = 0 and -1) coupled with relevant maximum stresses, as is shown in Table 1. In order to quantify the plate stability, the fatigue life has been generated via novel computational strategy using Eq. (3)-(10) associated with Eq. (2). Damage tolerance-based estimates are shown in Fig. 2a, 3a and Fig. 2b, 3b for stress ratio equal to R = -1, whereas those in the case of R = 0 are plotted in Fig. 4a and 4b with respect to depth and surface crack growth directions. Further, through the predictive-capacity model verification herein examined, experiments discussed by Grover et al. (1953) and relevant outcomes generated in a previous work of the present authors were employed, as is shown in Table 1. In this context, from the fatigue-critical analysis (see Table 1 and Fig. 2 to Fig. 4) it can be concluded that, with respect to literature-based experiments, estimates evaluated through the present research work are slightly more conservative than those generated via the computational strategy previously developed by Boljanović and Carpinteri, (2020).