Etude des perturbations vibratoires des dalles de montage dans un laboratoire de fabrication mecanique

The subject of this thesis is the study of the propagation of vibrations through the flagstones of CNC machine tool in the Laboratoire en fabrication virtuelle (LRFV) at Ecole Polytechnique de Montreal.; Precision tools used in that laboratory can be affected by different types of perturbation: machine tool working, air conditioning, lighting, electric systems, people working in the laboratory, or external major perturbations like construction work. However, we limit this study to the possible diffusion of perturbation between the flagstones of the machine tool setup. In this preliminary study, we want to find out if those perturbations are transmitted from one flagstone to another, and with which order of magnitude.; We conduct three types of tests. First, we test with a vibration measurement standard and secondly with three accelerometers simultaneously with a low amplitude perturbation to verify that the frequency content is really repeatable and that the amplitude varies slightly. A repeatability study with hierarchical design is conducted to evaluate the impact of the accelerometer setup and the use of different types of bases on amplitude. We determine that the most important cause of variation is not the type of base used but the variability in the actual setup done by the tester. Furthermore, the setup variance modifies the experiment repeatability from +/-2sigma to +/-2 5 sigma.; We evaluate the impact of the background excitation on the different flagstones when all machines are off. Results indicate that in addition to the background excitation, some intermittent phenomena cause an amplitude variation of 10 to 15 %. (Abstract shortened by UMI.)...