Issue 45

L. Zou et alii, Frattura ed Integrità Strutturale, 45 (2018) 53-66; DOI: 10.3221/IGF-ESIS.45.05

Figure 4 : Loading mode of T-joint specimen .

Load frequency （ HZ ）

Cycle numbers when crack （ ×10 6 ）

Specimen number

Fracture location weld toe weld toe weld toe without fracture weld toe weld toe without fracture weld toe without fracture weld toe weld toe weld toe weld toe without fracture without fracture weld toe without fracture without fracture weld toe weld toe

max  MPa 75.0 70.0 80.0

Material

note

1-1 1-2 1-3

163 174 171

0.4521 0.9885 0.2257

Clip holding problem

＞ 10

1-4

151

60.0

1-5 1-6

150 159

70.0 60.0

2.08

3.3749

5A06+5083

＞ 10

1-7

163

55.0

1-8

162

60.0

4.3542

＞ 10

1-9

159

55.0

1-10

171 158 158 159

60.1 80.0 70.0 40.0

5.7485 0.2729 0.7759 8.7281

2-1 2-2 2-3

＞ 10

2-4

164

35

＞ 10

2-5

170

37.5

Weld toe is not fused

5A06+5A06

2-6

172

40.0

4.3287

There is a scratch 2 mm around the weld toe

2-7

172

37.5

9.3184

＞ 10

2-8

170

35

＞ 10

2-9

170

37.5

2-10

170

40.0

6.3685

Table 6 : Three-point bending fatigue test data of T-joints .

where max 

is computed through Eqn. (7)~(9), which is the maximum bending fatigue stress, M is the maximum bending

moment,  is the anti-bending section coefficient, F is the load applied, L S

is the distance between pivots, b is the width

of the specimen, h is the thickness of the specimen.

M

(7)



=

max



4 FL S

(8)

M =

59