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Damage detection in composite laminates aeronautics structures through accelerometers networkOver the past twenty years, the increase of use of structural materials in Aerospace is due to many reasons. While the properties of metallic materials are mastered, the risk behavior of composite materials requires monitoring of the structure. That's why many methods of non-destructive testing (NDT) have been implemented and applied for the evaluation of defects in composites.The purpose of our research is the development of a new NDT tool for detecting delamination damages in aircraft's structures. The principle diagnostic is based on the application of a reproducible impact wave on a composite panel and its propagation trough an accelerometer sensor network. The presence of defects will be identified by the temporal and frequency response change compared to calibrated reference recorded before the damage.Therefore, in this paper an experimental study of impact behavior of a composite laminate structure will be presented. The panel is made from a guarded composite long carbon fiber laminate. In the study, the shock propagation wave induced in the materials will take into account the fiber orientation (0°, 45°, 90°, -45°) and plies arrangement (plies stacking sequence of tilt-up). First results of this new NDT for detecting damages of an aircraft structure composite demonstrate the wide possibilities of this technique.

System level simulation results of a planar electrostatic micromotor, based on analytical models of the static and dynamic torque behaviours, are presented. A planar variable capacitance (VC) electrostatic micromotor designed, fabricated and tested at LAAS (Toulouse) in 1995 is simulated using the high level language VHDL–AMS (VHSIC (very high speed integrated circuits) hardware description language–analog mixed signal). The analytical torque model is obtained by first calculating the overlaps and capacitances between different electrodes based on a conformal mapping transformation. Capacitance values in the order of 10⁻¹⁶ F and torque values in the order of 10⁻¹¹ N m have been calculated in agreement with previous measurements and simulations from this type of motor. A dynamic model has been developed for the motor by calculating the inertia coefficient and estimating the friction-coefficient-based values calculated previously for other similar devices. Starting voltage results obtained from experimental measurement are in good agreement with our proposed simulation model. Simulation results of starting voltage values, step response, switching response and continuous operation of the micromotor, based on the dynamic model of the torque, are also presented. Four VHDL–AMS blocks were created, validated and simulated for power supply, excitation control, micromotor torque creation and micromotor dynamics. These blocks can be considered as the initial phase towards the creation of intellectual property (IP) blocks for microsystems in general and electrostatic micromotors in particular.