Mesure the velocity of your fluids with utrasound
Testing and analysis techniques to monitor your equipments, materials and structures to reduce maintenance costs.
Non-invasive monitoring technique using ultrasound
Study of the propagation of sound in water for oceanology, defense, fishery…
Piezoelectric vibration absorbers for a large range of applications
Make the most of your vibrations: turn your them into electricity !
High-performance valves for the hydraulic sector
A unique and innovative technology for renewable energy
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Use of piezoelectric transducers to detect ice and defrost equipments
Piezoelectric actuators adapted to your solution
High-efficiency power transmission technology
Piezoelectric vibration absorbers for a large range of applications
Testing and analysis techniques to monitor your equipments, materials and structures to reduce maintenance costs.
Study of the propagation of sound in water for oceanology, defense, fishery…
A unique and innovative technology for renewable energy
Innovative piezoelectric generator for renewable energy
Make the most of your vibrations: turn your them into electricity !
Use of piezoelectric transducers to detect ice and defrost equipments
High-efficiency power transmission technology
High-performance valves for the hydraulic sector
Mesure the velocity of your fluids with utrasound
Non-invasive monitoring technique using ultrasound
26th January 2023
Thanks to various projects, PYTHEAS Technology has gathered unique skills and knowledge on vibration control. Our website page dedicated to vibration control describes this subject and you will find in this article more information about vibration absorbers and PYTHEAS Technology’s resonators.
First of all, let’s dive into the fundamentals of vibration control.
Every structure has normal modes. This means that when it is excited at some specific frequencies, which are called natural frequencies, resonance frequencies or eigenfrequencies, the structure responds with a large vibration amplitude. Each structure has an infinity of normal modes and vibration control usually focuses on the first ones, at the lowest frequencies, which cause important displacements.
We can observe the resonance phenomenon on the graph opposite, where the oscillation amplitude is increased in the vicinity of a specific frequency.
The maximum of the oscillation amplitude, in black, is represented as a function of the excitation frequency. We can see that we have a peak indicating it is the resonance frequency.
The goal of vibration control is to limit the effect of this resonance frequency to restrict the movement of the structure under study. To achieve this goal, we can a vibration absorber to control the structure by harvesting and dissipating the vibrational energy.
This peripheral device can be mounted on a structure and is designed to absorb and disperse the vibrational energy, which could result in significant oscillations of the structure.
There are different applications and objectives motivating the use of such absorbers:
The use of a Tuned Mass Damper (TMD), or harmonic absorber, is quite common due to its simplicity of design and use. We can simplify the TMD’s representation as a counter-mass mounted on a spring-damper.
When the TMD is used at the frequency it has been designed for, it will oscillate and dissipate a portion of the energy causing the structure’s resonance. We can see on the graph opposite that the structure’s vibration (in blue) is reduced.
Using a TMD limits the structure’s displacement amplitude.
Piezoelectricity is in PYTHEAS Technology’s DNA. Among other innovative devices, we have developed piezoelectric vibration absorbers, also called piezoelectric resonators.
Adding piezoelectric elements, piezoceramics or patches of different sizes and shapes, allows an electromechanical energy conversion to happen. The piezoelectric element can convert part of the vibration’s mechanical energy into electrical energy. An electronic circuit, called “shunt”, is connected to the piezoelectric element to collect and disperse the extracted electric energy.
Piezoelectric resonators present better performances than usual TMDs with similar added mass (purple curve). This performance improvement is due to the electromechanical energy conversion and the shunt used to dissipate the vibration energy.
Coupling the piezoelectric element with « smart » electronics can provide attractive properties. For instance, the resonant frequency of the absorber can be adjusted to follow evolutions of the structure or several frequencies can be processed with a unique device.
The use of piezoelectricity presents another advantage: in addition to dissipating and reducing parasitic vibrations, piezoelectric resonators can be used to develop energy harvesting solution. Instead of dissipating the electrical energy generated by the piezoelectric materials, we can harvest part of this electricity, which can be stored and exploited.
