Issue 68

L. M. Torres Durante et alii, Frattura ed Integrità Strutturale, 68 (2024) 175-185; DOI: 10.3221/IGF-ESIS.68.11

Figure 4: Numerical simulation to obtain the stresses generated with 7 µm of displacement.

The simulation results revealed that applying a displacement of 7 µm to the specimen generates an approximate stress of 94 MPa in its narrow section. As this value falls within the elastic range, linear behavior is considered. Other linear values are listed in Tab. 6, following the linear relationship between voltage – displacement at the free end – stress.

Total deformation (m)

% of yield stress of 304 (276 MPa)

Displacement (µm)

% of yield stress of 316 (289.6 MPa)

Voltage (v)

Stress (Pa)

10 12 14 16 18 20 21 22 23 24 25 26 27 28

7

9.39×10 7 1.13×10 8 1.31×10 8 1.50×10 8 1.69×10 8 1.88×10 8 1.97×10 8 2.07×10 8 2.16×10 8 2.25×10 8 2.35×10 8 2.44×10 8 2.53×10 8 2.63×10 8

7.00×10 -6 8.40×10 -6 9.80×10 -6 1.12×10 -5 1.26×10 -5 1.40×10 -5 1.47×10 -5 1.54×10 -5 1.61×10 -5 1.68×10 -5 1.75×10 -5 1.82×10 -5 1.89×10 -5 1.96×10 -5

32.42 38.90 45.39 51.87 58.35 64.84 68.08 71.32 74.56 77.80 81.05 84.29 87.53 90.77

34.02 40.82 47.62 54.42 61.23 68.03 71.43 74.84 78.24 81.64 85.04 88.44 91.84 95.24

8.4 9.8

11.2 12.6

14

14.7 15.4 16.1 16.8 17.5 18.2 18.9 19.6

Table 6: Linear relationship between Voltage-Displacement-Stress.

E XPERIMENTAL RESULTS ltrasonic fatigue tests were conducted on stainless steel 316 and 304 under two modalities: at room temperature and under immersion conditions. Stainless steel 316 was immersed in water, while stainless steel 304 was immersed in antifreeze. In tests conducted at room temperature in both denominations of stainless steel, it was not possible to establish a clear ultrasonic fatigue behavior pattern. This can be attributed to the poor heat dissipation properties of stainless steels, U

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