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Improving Lamb Wave detection for SHM using a dedicated LWDS electronics
19 June 2023
In the context of Condition Based Maintenance (CBM) for aircrafts, Structural Health Monitoring (SHM) is one main field of
research. Detection and localization of damages in a structure request reliability of the equipment and repeatability of the measurements and process. An electronic device called Lamb Wave Detection System (LWDS) have been developed and manufactured to manage piezo-electric patches either in emission or reception mode with a high commutation rate. Besides, integration of the piezo patches is another crucial aspect of reliability. Several methods as modelling and dispersion curves can define the frequency range of Lamb waves to optimize the piezo-electric coupling.
This work which takes part of the H2020 ReMAP project about adaptative aircraft maintenance planning, is presented in the article.
Self-tuning semi-active tuned-mass damper for machine tool chatter suppression
19 June 2023
Tuned mass dampers are simple and efficient devices for suppression of machine tool chatter, which is one of the principal effects limiting productivity in many machining processes. However, their effectiveness depends on a proper tuning of the damper dynamics to the dynamics of the machine. This involves the dynamic characterisation of the machining process, in order to identify the critical resonance frequency, and the possibility of matching the resonance frequency of the damper to frequency. The difficulty of meeting these two requirements has been limiting the use of tuned mass dampers in industrial applications.
Valves based on amplified piezoelectric actuators
6 January 2002
Amplified Piezo Actuators have been developed at CEDRAT TECHNOLOGIES for several years. Their well – known advantages (rapid response and precise positioning) have been used in valve designs to obtain both rapid or fine proportional valves.
Eddy current sensors on Printed Circuit Board for compact mechatronic application
19 June 2023
In a contact of always smaller and smarter mechatronics devices, the needs of more integrated sensors becomes critical. Particularly, small mechanisms using small actuators like piezo actuators require compact sensors, with performances that measure up to the actuators characteristics.
Investigations on a directly coupled piezoactuated tool feed system for micro electro discharge machine
19 June 2023
A directly coupled piezoactuated tool feed mechanism is proposed and a prototype micro-electrodischarge machine (micro-EDM) is developed. The piezoactuator is used to feed the tool and also to sense the tool displacement from a reference position. The hysteresis behavior of the piezoactuator is also incorporated through an electromechanical model for estimating the actual tool displacement. Simulation results for piezoactuator displacement are compared with the experiment and a maximum error of 15% was observed. Further, in order to control the tool feed rate during machining, a tool feed controller based on the gap voltage feedback is developed.
Semi-passive vibration control technique via shunting of Amplified Piezoelectric Actuators
12 January 2016
The objective of this paper is to provide results of an experimental and analytical investigation of Amplified Piezoelectric Actuators (APA) as vibrational isolator in a configuration of a mechanical Single Degree of Freedom system. The investigation is aimed at assessment of the mechanical properties modification ability via shunting techniques. The investigation consist of a phenomenological modelling of the APAs considered as generators and experimental verification of the vibrational energy dissipation ability in frequency domain. The results obtained during this investigation reveal that it is feasible to receive more than 20 dB reduction of the displacement amplification in the resonant range. Moreover, three tested examples of APA reveal up to 9 % of resonant frequency shift due to proper adjustment of the electronic shunting circuit, which is an encouragement for further analyses towards application of the APAs in semi-passive vibration control applications.
