PSI - Issue 38

Christophe Grosjean et al. / Procedia Structural Integrity 38 (2022) 94–108 C.Grosjean and al. / Structural Integrity Procedia 00 (2021) 000 – 000

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6

a

b

Fig. 4. (a) Modified drawing to correctly fill the mold. (b) Part produced by LWC.

5. Static tests Prior to these tests, each part was machined on the flat surfaces at the inlet and outlet of the channel to ensure proper sealing and assembly. A groove was machined on one side. Each of the three configurations presented above has been pressure tested at room temperature. The screws/bolts of the shut-off and connection flanges are individually tightened to 59 N.m. Each hydraulic block is pre-filled with oil to purge air from the internal volume. Hydraulic pressure is then applied at the set point of 840 bar, with a dwell time of 10 minutes. The pressure is then increased until a failure is observed. For all the parts tested, it was a leak by extrusion of the seal that led to the test being stopped with a pressure around 2000 bars (see Table 3). For LWC configuration an additional deformation was noticed (see Fig. 5)

Table 3. Results of pressure tests.

Maximum pressure reached Observation

L-PBF 2 090 bars, 2 134 bars

Seal extrusion Seal extrusion

MBJ LWC

1897 bars 2039 bars

Seal extrusion+ deformation

a

b

Fig. 5. (a) Hydraulic bloc during tests with the inlet at the top left the outlet obturated at the bottom right. (b) Deformation on the LWC part.

6. Pressure drop test Pressure drop measurements were performed to compare the historical machined design with that obtained by L PBF. For an HM46 oil (ISO VG46), an oil temperature of 42°C +/- 2°C, and a flow rate between 40 and 200 L/min, the pressure drop of the AM hydraulic block is between 2.4 and 3.5 times lower than that measured on the original block made in conventional machining (see Fig. 6).