3D Printed Architected Metamaterials

Architected metamaterials can manipulate and control stress wave propagation through spatial variations of the geometry and composition.  Such design strategies lead to tailored materials and structures that are multifunctional and can satisfy conflicting design requirements, such as high stiffness and strength properties while also mitigating vibrations, attenuating sound, and absorbing impacts.

Why does this matter?

One of the “grand challenges” for material and structure design is to satisfy multiple and oftentimes conflicting design requirements. Energy infrastructure, especially in remote and extreme environments e.g. offshore wind turbines and advanced nuclear reactors, requires components to operate effectively over long time periods and prevent catastrophic failures. Structural materials in e.g. aviation must be lightweight but high in strength, stiff while dampening out harmful vibrations, and survive damaging impact events. Addressing similar challenges on the small scale, through material design for sensors and other MEMS devices, can greatly advance biomedical imaging capabilities and ultrasonic sensing techniques. By designing multifunctional and tailored materials and structures that control wave propagation and mechanical properties on multiple length scales, we can ensure safe and efficient operation of structures and components, resulting in large energy and material cost savings.

Current Work

In this research, we are designing, modeling, and testing new elastic metamaterials that control mechanical wave propagation. We are developing a class of materials (labeled elastic metastructures) that supports the formation of wide and low-frequency band gaps, while simultaneously reducing their global mass. To achieve these properties, the metastructures combine local resonances with structural modes of a periodic architected lattice.  Whereas the band gaps in these metastructures are induced by Bragg scattering mechanisms, their key feature is that the band-gap size and frequency range can be controlled and broadened through local resonances, which are linked to changes in the lattice geometry.  With advanced 3D printing capabilities, we can fabricate a wide range of geometric and composite structures on different length scales.  We  experimentally measure the band gaps in 3D printed meta-structures, and inform our designs using finite-element simulations.  This design strategy has a broad range of applications, including control of structural vibrations, noise, and shock mitigation.

Press: ETH News, Lattice Structure Absorbs Vibrations

Experimental validation of band gap shift in frequency between high and low stiffness metastructures. Here, we use piezoelectric actuation to excite vibrations in the metastructure, and accelerometers to detect the response over a swept frequency range.

Top: Metastructure design for high stiffness (left) and low stiffness (right) Middle: Photograph of metastructure mid-print, after insertion of steel particles. Bottom: Final 3D printed metastructure.

 

 

 

 

 

 

 

 

 

 

 

Journal Publications:

K.H. Matlack, A. Bauhofer, S. Krödel, A. Palermo, C. Daraio, “Composite 3D printed meta-structures for low frequency and broadband vibration absorption,” PNAS, vol. 113 (30), p. 8386-8390, 2016.

Conference Presentations:

K.H. Matlack, A. Kissling, A. Palermo, C. Daraio, “Auxetic elastic meta-structures for vibration mitigation,” SES 53rd Annual Technical Meeting, Hyattsville, Maryland, October 2-5, 2016.

K.H. Matlack, A. Palermo, S. Krödel, A. Bauhofer, C. Daraio, “Controlling band gaps with geometry in composite elastic meta-structures,” ICTAM, Montreal, Canada, August 21-26, 2016.

K.H. Matlack*, C. Daraio, “Mode engineering in 3D-printed elastic meta-structures,” 2015 MRS Fall Meeting and Exhibit, Boston, MA, Nov 29-Dec 4, 2015.

K.H. Matlack*, S. Krödel, A. Bauhofer, C. Daraio, “Advanced structured composites as novel phononic crystals and acoustic metamaterials,” SEM 2015 Annual Conference and Exposition on Experimental and Applied Mechanics, Costa Mesa, CA, June 8-11, 2015.

K.H. Matlack*, C. Daraio, “Geometry Effects in Locally Resonant Acoustic Meta-structures,” Phononics 2015: 3rd International Conference on Phononic Crystals/Metamaterials, Phonon Transport and Phonon Coupling, Paris, France, May 31 – June 5, 2015.