Making waves in acoustics research

Acoustics is not just about audible sound. This scientific field covers a wider range, including ultrasound and elastic waves propagating in solids, says Chen Shen, assistant professor of mechanical engineering in the Henry M. Rowan College of Engineering. Supported by a National Science Foundation Faculty Early Career Development Program (CAREER) Award and other funding, Shen has made acoustics the centerpiece of his research. 

One of Shen’s research topics, novel structures that can control the propagation of waves in complex media, has numerous practical applications. Take the example of millimeter-sized microrobots, used as environmental sensors. At that scale, traditional motors and propellers are often too large or inflexible to be effective. Instead, focused and concentrated acoustic waves can move and guide microrobots. 

Shen and team developed a 3D printed acoustic lens, which attaches to the robot along with a transducer. The acoustic lens focuses sound waves generated by a transducer, allowing the robot to be steered without any moving parts. 

The acoustic lens is just one example of a novel structure Shen has developed. In another project, Shen demonstrated how acoustic waves can be dampened. His team developed a 3D printed silencer with folded fins that redirect sound waves while preserving airflow. 

Because acoustic waves are safe and don’t interact or otherwise interfere with human tissue, they can also be used in biomedical applications. Surface acoustic waves pulsed on the surface of a microchip can sort hundreds of cells based on how they respond to sound, helping researchers accelerate diagnoses. 

The author of numerous academic papers in the field of acoustics, Shen is excited to see years of fundamental research translated into practical applications. 

“Whether it’s biomedical research or structural engineering, acoustics has a lot of potential to tap into. The future is full of exciting possibilities,” Shen says.

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This material is based upon work supported by the NSF under Award No. 2337069. Any opinions, findings and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the NSF.