PSI - Issue 38

Benaouda Abdellaoui et al. / Procedia Structural Integrity 38 (2022) 116–131 Benaouda Abdellaoui et al / Structural Integrity Procedia 00 (2021) 000 – 000

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5.2. Test condition The pivot has been tested in an ambient environment with 2 hydraulic cylinders following 2 different stress axes shown in Fig. 7. The test conditions are as follows:

Specimen shape: Pivot, see Fig. 2

• •

(6)

= = 0.1

Stress ratio:

Test control [12]: effort Signal: sinusoidal shape

• •

• Test frequency: 1Hz to 6Hz in force controlled, • Fatigue life target: between 10 cycles and 10 6 cycles, • Stopped criteria: specimen failure or achieve 10 6 cycles for the 1st level and the next levels will be incremented by 10 5 with a step of 0.25KN (locati method [9]) 5.3. Test results We carried out on the first pivot, 2 static tests up to 5KN coupled with digital image correlation (DIC) to determine how the part works exactly, the level of fatigue to be applied in order to obtain an endurance limit at 1,000,000 cycles, to observe the deformation fields and improve the simulation. The principle of digital image correlation is to compare a reference image with an image obtained in the distorted state with an optical, non-contact 3D measurement technique. The areas observed with the DIC in Fig. 9 are those that were revealed with the simulation calculation. We placed 2 virtual gauges on the areas corresponding to the hot spot to observe the behaviour of the pivot subjected to a force of 5 KN. The 3 graphs from bellow Fig. 9 show the displacement in the x, y and z directions of the 2 virtual gauges.

a)

b)

c)

Fig. 9. Displacement along the X (a), Y(b) and Z(c) axis