Lattice materials show exotic quasi-static and wave propagation properties by virtue of their geometric configuration and periodicity. These materials have a higher stiffness-to-weight ratio that opens a new regime in the material property space. While being lightweight, their periodic nature forbids a band of certain frequencies from propagating through the material, making them a strong candidate for structural vibration isolation. However, understanding both the quasi-static and vibration properties of lattice materials simultaneously, together with their optical, electrical, and thermal properties, is crucial for these materials to be used in real-world applications. In this project, we address this challenge by designing multifunctional lattice materials that exhibit multiple properties simultaneously.
First, we implemented the Bloch-wave homogenization method on 3D lattice materials to form a link between their wave propagation and quasi-static properties [Patil and Matlack, JASA, 2019]. This interactive approach allows one to simultaneously analyze the static and dynamic properties of periodic lattice materials. Using this tool, we analyzed various lattice geometries that included several symmetries, anisotropies, and distinct deformation patterns. More specifically, cubic, octet, Kelvin, hexagonal and auxetic lattices were studied with an emphasis on how geometric parameters affect their static as well as wave propagation properties. Next, using the developed “Bloch-wave homogenization” method, we showed how auxetic lattices can be designed to control the polarization of the fastest propagating wave. We demonstrated that auxetic lattices can exhibit “anomalous polarization”, where shear waves travel faster than longitudinal waves, which is rarely observed in natural materials. With this additional functionality, we showed that auxetic lattices can decelerate longitudinal waves while simultaneously accelerating shear waves, which could have applications in a wave-based actuator [Patil et al., App. Phy. Lett. 2019].
Further, we simultaneously studied heat transfer and vibration properties in phononic materials, by incorporating heat pipes within the lattice beams and nodal masses at the truss junctions. Heat pipes can transport thermal energy more effectively than would be possible through a solid bar made of the same material due to the phase change of fluid while nodal masses control the dynamic mass of the lattice materials. Such design showed dual-functionality of lattice materials, where they can isolate vibrations while at the same time exhibit vastly improved thermal conductance, both of which could be tuned independently with our proposed design [Babatola et al., Adv. Engg. Matl., 2020]. These dual-functional lattice materials have thermo-mechanical applications in automotive, aerospace, energy, and transportation engineering.
- O. Babatola, G. U. Patil, D. Hsieh, K. H. Matlack, S. Sinha, Independently tunable thermal conductance and phononic bandgaps of 3D lattice materials. Advanced Engineering Materials, vol.22(2), 1901004(2019) https://doi.org/10.1002/adem.201901004
- G. U. Patil, A.S. Shedge, K. H. Matlack, 3D auxetic lattice materials for anomalous elastic wave polarization. Applied Physics Letters, vol.115, 091902 (2019) https://doi.org/10.1063/1.5116687
- G. U. Patil, K. H. Matlack, Effective property evaluation and analysis of three-dimensional periodic lattices and composites through Bloch-wave homogenization. The Journal of the Acoustical Society of America, vol. 145, 1259–1269 (2019) https://doi.org/10.1121/1.5091690
- G. U. Patil, O. Babatola, D. Hsieh, S. Sinha, K.H. Matlack, Three-dimensional periodic multifunctional lattice materials for simultaneous vibration isolation and heat conduction. 179th ASA Meeting, Acoustics Virtually Everywhere, 7-11th December 2020 https://doi.org/10.1121/1.5147155.
- G. Patil, K.H. Matlack, Anomalous wave polarization through a 3D periodic auxetic lattice. The Journal of the Acoustical Society of America, vol. 145, 1666 (2019) https://doi.org/10.1121/1.5101115
- I. Arretche, G. Patil, K.H. Matlack, Effects of geometry and mass distribution in 3D printed metastructures for vibration mitigation. The Journal of the Acoustical Society of America, vol. 145, 1760 (2019) https://doi.org/10.1121/1.5101444