PSI- Issue 9

O.H. Ezeh et al. / Procedia Structural Integrity 9 (2018) 29–36

32

4

Author name / Structural Integrity Procedia 00 (2018) 000–000

Table 1. Summary of the results from the statistical re-analyses.

Fabrication Technology

(a)

 UTS

 MAX, 50%

 f

R

k

Reference

T 

[MPa]

[MPa]

[ ° ]

Letcher et al. (2014) Letcher et al. (2014) Letcher et al. (2014) Afrose et al. (2016) Afrose et al. (2016) Afrose et al. (2016) Averett et al. (2011)

AM AM AM AM AM AM

0

58.5 64.0 54.0 38.7 31.1 33.6 58.0

-1 -1 -1

5.1 6.4 4.8 6.9 5.9 5.1 5.0

7.4

1.579 1.422 1.415 1.159 1.207 1.324 1.397

45 90

11.0

6.2 4.9 5.0 3.4 9.8

0

0 0 0 0

45 90

Standard

-

(a) Endurance limit extrapolated at N

0 =2ꞏ10

6 cycles to failure.

Filament Orientation  f =0 °

Filament Orientation  f =45 °

100

100

Run Out

Run Out

 UTS =64 MPa

 UTS =58.5 MPa

P S =10%

P S =10%

 max [MPa]

 max [MPa]

k=6.4

P S =50%

P S =50%

k=5.1

P S =90%

10

10

P S =90%

 0, 50% =7.4 MPa T  =1.579

 MAX, 50% =11.0 MPa T  =1.422

R=-1

R=-1

N 0 =2  10

N 0 =2  10

6

6

1

1

100

1000

10000

100000 1000000 10000000

100

1000

10000

100000 1000000 10000000

N f [Cycles to Failure]

N f [Cycles to Failure]

(a)

(b)

Filament Orientation  f =90 °

100

100

Run Out

Run Out

= 0° = 45° = 90°  f  f  f

UTS =54 MPa



P S =10%

 max [MPa]

 max [MPa]

P S =10%

P S =50%

P S =50%

k=4.8

k=5.2

10

10

P S =90%

P S =90%

 MAX, 50% =6.2 MPa T  =1.415

 MAX, 50% =7.6 MPa T  =1.836

N 0 =2  10

6

R=-1

R=-1

N 0 =2  10

6

1

1

100

1000

10000

100000 1000000 10000000

100

1000

10000

100000 1000000 10000000

N f [Cycles to Failure]

N f [Cycles to Failure]

(c) (d) Fig. 2. S-N curves determined by post-processing the experimental results generated by Letcher and Waytashek (2014). The charts of Figures 2a to 2c together with Table 1 show that both k and  MAX, 50% are not influenced markedly by manufacturing angle  f , with the fatigue strength being directly related to the static strength. Owing to the high level of consistency between data sets generated by testing specimens with different values for angle  f , the same results were also re-analyzed together as shown in Figure 2d. This chart confirms that, similar to what is observed under static loading (Ahmed, Susmel 2018), also the fatigue results obtained from specimens with