Publications
Categories
In-situ monitoring of μm sized electrochemically generated corrosion pits using Lamb waves managed by a sparse array of piezoelectric transducers
2 December 2024
Corrosion is a major threat in the aeronautic industry, both in terms of safety and cost. Efficient, versatile, and cost affordable solutions for corrosion monitoring are thus needed. Ultrasonic Lamb Waves (LW) appear to be very efficient for corrosion monitoring and can be made cost effective and versatile if emitted and received by a sparse array of piezoelectric elements (PZT). A LW solution relying on a sparse PZT array and allowing to monitor μm-sized corrosion pit growth on stainless 316L grade steel plate is here evaluated. Experimentally, the corrosion pit size is electrochemically controlled by both the imposed electrical potential and the injection of a corrosive NaCl solution through a capillary located at the desired pit location. In parallel, the corrosion pit growth is monitored in-situ every 10 s by sending and measuring LW using a sparse array of 4 PZTs bonded to the back of the steel plate enduring corrosion. As a ground truth information, the corrosion pit volume is estimated as the dissolved volume balancing the electronic charges exchanged during corrosion. The corrosion pit radius is additionally checked post-experiment precisely with an optical measurement. Measured LW signals are then post-processed in order to compute a collection of synthetic damage indexes (DIs). After dimension reduction steps, obtained DI values correlates extremely well with the corrosion pit radius. Using a linear model relating those DI values to corrosion pit radius, it is demonstrated that corrosion pit from 30 μm to 150 μm can be reliably detected, located, and their upcoming size extrapolated. Two independent experiments were achieved in order to ensure the repeatability of the proposed approach. LW managed by a sparse PZT array thus appears to be reliable and efficient to monitor growth of μm-sized corrosion pits on 316L steel plates. If embedded in aeronautical structure, such an approach could be a versatile and cost-effective alternative to actual non-destructive maintenance procedures that are time and manpower consuming.
Magnetic Fast Steering Mirror For High Power Feeder Links Applications
25 November 2024
To cope with performances of Fine Pointing, and Fast Steering mirror requirements for Space Optical Communication, CEDRAT TECHNOLOGIES (CTEC) is developing magnetic Fast Steering Mirror’s (M-FSM) family, based on proprietary MICA™ flexure bearing magnetic actuators mechanism (Moving Iron Controllable Actuator), with embedded eddy current sensors (ECS).
FSM design expected for Optical Inter-Satellite Link (OISL) in large-scale New Space constellations is highly driven by mandatory cost-efficiency for high quantities recurrent production, while FSM design expected for Feeder-Link communication is driven instead by high power Laser requirements together with high level of redundancy.
In this publication CTEC is presenting both the M-FSM45 and M-FSM45-HPL designs, and test results, respectively for inter-satellites and feeder link optical communications.
Light-controlled mechanisms based on photomobile polymers for seamless integration in demanding environments
14 June 2024
Photomobile polymers (PMP) are active materials that convert light into mechanical movement. They can be used in energy harvesters, light-controlled actuators, or mechanisms. Because they are controlled by light and work without electricity, they offer unique opportunities for designing devices that can be integrated seamlessly and that require virtually no maintenance. This finds interest in fields like nuclear energy, medical implants, biology, space, or Internet of Things (IoT). Cedrat Technologies have designed, built, and tested 3 proof of concept prototypes: a mechanical switch, a mechanical valve, and an optical deflector. The present paper will present these 3 concepts and the tests results in detail.
Inertial & Inchworm piezoelectric motors: Design and Motorization selection key aspects
14 June 2024
Piezoelectric motors have gained increasing prominence in various applications due to their unique capabilities and advantages. These motors are adapted for applications which require non-magnetic and radiation compatibility, high force/volume ratio, good unpowered stall force and low power consumption. Cedrat Technologies (CTEC) have developed inertial and inchworm motorization for a wide range of application such as Space, Defense and Nuclear. Each motorization solution has its own advantages and disadvantages which are discussed in this paper. Key aspect for the design and key element for the motorization selection are presented below.
Miniature Piezo Fast Steering Mirror for Optical Communication in NanoSats and CubeSats
14 June 2024
Access to data has become vital and strategical for individuals and nations, Earth planet preservation and monitoring, and mobility applications. In this context, the number of satellite constellations projects is growing drastically worldwide and is a next generation challenge of the New Space cost efficient industry.
To replace radio frequencies (RF) communications, space optical communication will be the new trend, addressing both very high speed and as secured encrypted communication improvements.
Fast Steering Mirrors (FSM) are a key component used in optical communication, and for a large field of functions such as Point Ahead Mechanisms (PAM), Raster Scanning, Beam Steering Mirrors (BSM), Fine Pointing Mechanisms (FPM) and Line of Sight stabilization (LOS).
The following paper presents test results of CEDRAT TECHNOLOGIES piezoelectric mini-FSM and associated CCBu20 driving electronics.
Optimized high-efficiency MICA actuators for space compressors
14 June 2024
Moving Iron Controllable Actuators MICA™ are magnetic linear actuators from CEDRAT TECHNOLOGIES (CTEC) that find interests in applications requiring high-force density and low heating. Because of these attractive performances, some space applications such as ZBO Gas compressors and Pulse Tube Cryocooler are considering their use in operational missions. However, this last application requires the demonstration of additional features, notably a high efficiency, a long lifetime and a good force homogeneity to minimize the generation of exported micro-vibrations. To fulfil these additional features, CTEC has developed an optimised MICA following the specifications of the Pulse Tube Cryocooler (PTC) of AIR LIQUIDE. The paper will present the performance progresses obtained on this customized MICA, from modelling prediction to lab tests of Engineering Models.
