FEATURE / PRE-PREG L AT TICE STRUCTURES Figure 4. 1.5 m diameter test article design. Left - Composite part. Right - Assembled with metal fixtures. Manufacturing Manufacturing of the large cylinder used the same process as was used for the small cylinder, scaled up for the larger cylinder. A large part of the flexible tooling was re-used from the manufacturing of the other cylinders and panel, as can be seen in Figure 5. Figure 6 shows the cured composite cylinder, before drilling and assembly with the fixtures. Testing Setup Testing was performed at National University of Ireland Galway, in conjunction with the Large Structures Research Group. Two separate types of tests were performed on the cylinder. Local loading of the cylinder was applied using a small hydraulic cylinder connected to the load introduction bracket, applying an in-plane load at an offset from the cylinder. This test simulates loading through e.g. a shear web in a satellite. Global loading was performed using two large actuators, which introduce the load through a large I-beam and load diffusion structure into the cylinder. By controlling both actuators separately both pure compression and combined compression and bending could be introduced. The test setup is shown in Figure 7. Results Following multiple low load level characterisation tests the design load cases were tested. Local loading of the cylinder through the load introduction bracket was applied up to the design load level of 6650 N. No signs of failure were observed during or after this test. During the test the displace- 10 | SAMPE JOURNAL | Figure 5. Large cylinder layup on the mandrel, before covering with caul plates. Re-used tooling clearly visible. Figure 6. Large cylinder as manufactured, shown here with the small cylinder. J A N UA R Y/ F E B R UA R Y 2 0 2 1 w w w. s a m p e . o r ghttp://www.sampe.org