PSI - Issue 26

Gonzalo M. Dominguez Almaraz et al. / Procedia Structural Integrity 26 (2020) 20–27 Almaraz et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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Figure 1. Dimensions (mm), and modal analysis of testing specimen Inconel 718.

Thermographic images were taken during ultrasonic testing with aim to determine the temperature distribution, which is associated with the stress distribution. In Figure 2 is presented the thermographic image showing the temperature distribution during the ultrasonic testing  9, 10  ; the higher values of temperature are located at the specimen neck section, where de the higher stresses are induced.

Figure 2. Thermographic picture taken on the Inconel 718, during the ultrasonic test.

Ultrasonic fatigue tests have been carried out on an ultrasonic fatigue machine designed and constructed in our laboratory, Figure 3a. Under ultrasonic fatigue tests a stationary elastic wave is developed along the testing specimen inducing higher stress at the neck section and higher displacement at its ends, as depicted in Figure 3b.

Figure 3. (a) Self-constructed ultrasonic fatigue machine, (b) Stationary elastic wave along the testing specimen.

The pre-corrosion on testing specimens was carried out following the norm ESA ECSS-Q-ST-70-37C of the European Space Agency: immersion in a solution of distilled water and 3.5% in weight of NaCl for 30 hours. In Figure 4 are presented specimens after the pre-corrosion process.