PSI - Issue 42

Rogério Lopes et al. / Procedia Structural Integrity 42 (2022) 1159–1168 Rogério F. F. Lopes et al./ Structural Integrity Procedia 00 (2019) 000 – 000

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After the chassis was finished, the exterior fiberglass produced by hand moulding and aluminium profiles were joined. When the metal hardware is in place, the process proceeds with the introduction of the components made of composite with fiberglass reinforcement. It is attached to the section headlights, which are made of the same material as the frame. Consequently, the attachment was replaced by metal hardware alternatives, resulting in a more cost effective prototype. The frontal windshield was fixed after the fiberglass panels were bonded. Sika 263 adhesive was used for this bonding. A thin metal sheet bonded with Sika 263 adhesive was utilized to replicate the side component on the driver's side. Two 20x20x1 mm square tubes were used to offer resistance at the entry door in order to replace the door sub-system stiffness. The construction was reinforced to prevent it from collapsing during transportation. Four 10mm thick steel bars were added to the framework to allow it to be lifted and so support the prototype deadweight. In order to acquire the deformation in dynamic regime, as well as the acceleration signals, two NI 9235 and two NI 9234 modules were used to read the signals from for the strain gauges and accelerometers respectively. The modules are installed in the cDAQ NI 9188 chassis, from the company National Instruments. The necessary instrumentation comprised 15 unidirectional 120 Ω impedance strain gauges, model 1 − 41 − 3/120 from HBM® at 2 KHz frequency sampling, and two triaxial accelerometers, model 356A17 from PCBPiezotronics. It is worth to note that the X, Y, and Z orientations for accelerometers correspond to the transverse, vertical, and longitudinal planes, respectively. Finally, it was agreed that the driver’s side would be monitored employing contactless technology. For this, a high-speed camera model Mini AX200 type 900, from Photron® is employed, to this purpose a 1000 fps high-speed video is recorded. Furthermore, the lateral side of the section was equipped to allow the measurement of the deformations and displacements of the exterior panels. A speckle painting, in which dots are randomly distributed, is beneficial for DIC non-contact deformation assessment of the door surface. To perform this test, a stiff frame was built and firmly anchored to the floor studs. The constructed frame is depicted in Fig. 3.a), which represents a suspended pendulum with one rotational degree of freedom. Fig. 3.b) represents the real pendulum structure.

a) b) Fig. 3. Representation of the pendulum: CAD model - (1) frame, (2) impactor, (3) impactor mass and b) experimental impactor of the ECE 29 test The regulation-mandated dummy is made of composite and weighs 12.55 . A weight of roughly 82 must be obtained by adding extra masses to the dummy to achieve a mass equivalent to a real adult with the driver's height. A rapid rate dynamic test typically necessitates applying a sudden load to the test specimen. In the current work, the swinging pendulum mass is raised up to the required level and locked in the position by a mechanical trigger. When this is released, the mass will travel in rotational trajectory and strikes the front of the coach structure. It is important to note that it may be necessary to check the initial pendulum falling height for the required kinetic energy purpose. Therefore, the mechanical trigger should be placed at a set of pre-defined levels. To avoid accidents during operation, such action is remotely performed via hydraulic pressure acting a small hydraulic cylinder displacing the