Acoustic metamaterials
Acoustic metamaterials have received particular attention in recent years due to their unique ability to manipulate and control sound waves. Although there is no consensus on the precise definition, acoustic metamaterials generally refer to engineered materials with unconventional, customized properties that surpass those of traditional acoustic materials.
Additive manufacturing plays an important role in the development of acoustic metamaterials, as it greatly simplifies their production. It also tends to blur the boundaries between acoustic materials and metamaterials.
High performances and customization
Sub-wavelength acoustic control for compact solutions
Acoustic metamaterials can handle sound waves on a sub-wavelength scale, i.e. with a thickness well below a quarter of the wavelength. This enables the development of compact acoustic solutions for noise absorption or attenuation.
Band gaps for open insulation solutions
Acoustic metamaterials with a periodic internal structure display band gaps. In the frequency ranges of these band gaps, sound propagation is strongly attenuated. These metamaterials make it possible to block the propagation of unwanted noise, while allowing air and light to circulate through the materials.
Ducts sound absorption solutions
Rather than simply blocking the propagation of sound in a duct and sending it back to the source, some systems can absorb it. Sound is neither reflected upstream nor transmitted downstream: it is absorbed.
Tailor-made acoustic properties to meet specific needs
Acoustic metamaterials are deliberately designed to meet specific performance requirements. They are therefore better suited to meeting unique rather than generic needs. That's why, to unlock the full potential of acoustic metamaterials, it's important to collaborate with experts in the field who can design tailor-made solutions to meet specific needs.
3D printed porous materials
Conventional porous materials are widely used to tackle noise problems. Their acoustic efficiency over wide frequency ranges combined with their low cost and density make them a great choice for generic applications.
However, conventional porous materials are limited by a lack of adaptability, rarely exploitable mechanical properties and undesirable variability in acoustic properties.
Additive manufacturing of porous materials seeks to retain their strengths while reducing their limitations.
High performances and multifunctionality
Simple geometric control for tailor made acoustic properties
3D printing enables us to control the size and shape of pores in porous materials simply and precisely. We can thus adjust their intrinsic behavior by varying both their porosity and resistivity. To extend the range of possible behaviors even further, we can work on their anisotropy, introduce gradients of properties or even fold their structure!
Precise geometric control for reliable acoustic properties and decentralized production
Once the 3D printer has been calibrated, the materials manufactured do not suffer from dispersion problems: their properties are controlled from one end of the material to the other, and from one batch to the next. What's more, additive manufacturing enables materials to be produced in a decentralized way. There's no need to set up a specialized factory, as one or more geographically distributed 3D printing farms can manufacture materials or finished products from CAD files.
Simple geometric control and wide choice of raw materials for multifunctional acoustic solutions
Controlling the size and shape of pores in porous materials enables their mechanical properties to be fine-tuned. The pores are designed to best respond to the mechanical stresses the material will undergo during operation. What's more, in most cases, the raw material used to 3D print a porous material does not determine its acoustic properties. This allows the raw material to be chosen according to the functional attributes required: mechanical or thermal properties, UV resistance, fire resistance, chemical resistance...