PSI - Issue 13

Przemysław Strzelecki / Procedia Structural Integrity 13 (2018) 631 – 635 Author name / Structural Integrity Procedia 00 (2018) 000–000

633

3

The parameters of the 3-parameter Weibull distribution for different geometry of specimens were estimated and show in Table 3. Figure 3 a) shows the microstructure of specimen. An example of the fracture surface under S a = 160 MPa at N = 101 591 for smooth specimen is shown in Fig. 3 b).

Table 1. Mechanical properties for the AW6063 T6. E , [MPa] S u , [MPa] S y , [MPa] A, [%] Z , [%] 69 556 243 201 75.5 10.5

a

b

Fig. 1. Geometry of the specimen for fatigue testing (a) smooth; (b) notched.

Table 2. Dimensions of the notched specimens. No. r , [mm] K t , [-] 1 1.5 1.4 2 0.5 2 3 0.25 2.6

50 100 150 200

Stress amplitude S a [MPa]

Unnotched specimen Notched specimen r=1.5 Notched specimen r=0.5 Notched specimen r=0.25

10 4

10 5

10 6

10 7

Number of cycles N

Fig. 2. S-N curves for AW 6063 T6 aluminium alloy

Table 3. Value of linear regression parameters. Geometry of specimen r , [mm] α v

m

b

n

d

Smooth Notched

25

2.31 3.11 3.43 3.29

-6.99 -6.65 -4.73 -4.37

20.52 19.15 15.04 14.06

-0.25 -0.40 -0.29 -0.38

1.02 1.00 1.00 1.01

1.5 0.5

0.25