PSI - Issue 2_B
Ralf Urbanek et al. / Procedia Structural Integrity 2 (2016) 2097–2104 Author name / Structural Integrity Procedia 00 (2016) 000–000
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3.1. Global effects in constant force and constant stress intensity experiments
The constant force experiments were performed with forces of 8.0 and 8.2 kN, the experiments with constant stress intensity at K max -values between 12.5 and 22.5 MPa √ m. According to previous experiments done by Bär et al. (2015) at the end of the experiments the temperature fields in front of the crack tip in the experiments with constant force were clearly asymmetric. To investigate the influence of the specimen motion and its compensation, the evaluation was undertaken in a rectangular section with 10 x 10 mm located adjacent to the notch as shown in Figure 3.
Fig. 3. Position of the analysis area
Figure 4 shows the mean E-Amplitude in the evaluation area with and without MC. No significant influence on the mean E-Amplitude due to the motion compensation is visible.
0,28
0,28
a
b
0,26
0,26
0,24
0,22
0,24
0,20
0,22
0,18
0,16
0,20
normal K=12,5 MC K=12,5 normal K=15 MC K=15 normal K=17,5 MC MC K=17,5 MC normal K=20 MC K=20 normal K=22,5 MC K=22,5
0,14
0,18 E-Amplitude [°C]
0,12 E-Amplitude [°C]
normal F=8kN MC F=8kN normal F=8,2 kN MC F=8,2 kN
0,10
0,16
0,08
0,14
0,06
1
2
3
4
5
0
1
2
3
4
5
6
7
8
9
crack length a [mm]
crack length a [mm]
Fig. 4 (a) mean E-Amplitude in experiments with constant force / (b) experiment with constant stress intensity
0,040
0,030
a
b
0,035
0,025
0,030
0,020
0,025
0,020
0,015
0,015
normal K=12,5 MC K=12,5 normal K=15 MC K=15 normal K=17,5 MC MC K=17,5 MC normal K=20 MC K=20 normal K=22,5 MC K=22,5
0,010
0,010 D-Amplitude [°C]
D-Amplitude [°C]
normal F=8kN MC F=8kN normal F=8,2 kN MC F=8,2 kN
0,005
0,005
0,000
0,000
1
2
3
4
5
0
1
2
3
4
5
6
7
8
9
crack length a [mm]
crack length a [mm]
Fig. 5 (a) mean D-amplitude in experiments with constant force / (b) experiment with constant stress intensity
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