In everyday materials, these are both positive.Ī close up of the team’s metamaterial. The mechanism relies on the abnormal properties of their metamaterials – negative modulus and negative density. Therefore, when an acoustic or mechanical wave contacts the material, it perturbs it, generating the unique properties that block sound waves and mechanical vibrations of certain frequencies from passing through. The magnetic field compresses the material, but unlike a physical contact force like a metal plate, the material is not constrained. Using magnetic fields, the switch is reversible and very rapid.” “We wanted to achieve this kind of freedom to switch between states. Once you change the architecture, you change the property,” Wang said. “You can apply an external magnetic force to deform the structure and change the architecture and the geometry inside it.
By 3-D printing a deformable material containing iron particles in a lattice structure, their metamaterials can be compressed using a magnetic field. The team’s metamaterials are able to control environmental sounds and structural vibrations, which have similar waveforms. Metamaterials can be used to manipulate wave phenomena such as radar, sound and light and have been used to develop technology such as cloaking devices and improved communication systems. The idea here is, we can design something very flexible so that you can change it using external controls,” said Wang, an assistant professor of civil and environmental engineering. “When you fabricate a structure, the geometry cannot be changed, which means the property is fixed. “Traditional engineering materials may only shield from acoustics and vibrations, but few of them can switch between on and off,” said Yu. Their materials can be used for noise cancellation, vibration control and sonic cloaking, which can be used to hide objects from acoustic waves. Unlike current metamaterials, these can be turned on or off remotely using a magnetic field. student Kun-Hao Yu, along with MIT Professor Nicholas Fang and University of Missouri Professor Guoliang Huang, have developed 3-D printed metamaterials capable of blocking sound waves and mechanical vibrations. USC Viterbi Assistant Professor Qiming Wang and Ph.D.
Now, new 3-D printed metamaterial developed by a team led by USC Viterbi researchers can be remotely switched between active control and passive states. However, these metamaterials are constructed in fixed geometries, meaning their unique abilities are always fixed. Researchers have been pushing the capabilities of materials by carefully designing precise structures that exhibit abnormal properties that can control acoustic or optical waves. The magnetoactive acoustic metamaterial (center front) affixed to a petri dish.
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