Research conducted at the Pratt School of Engineering at Duke University has resulted in the development of a thin material that redirects and reflects sound waves with almost perfect efficiency.
This new innovation which is the first material to demonstrate almost complete control of sound waves is made of 3D printed plastic. But it is not the properties of plastic that make it so effective, but rather the shape created by the plastic. Through an astounding amount of mathematical and simulation work, the structure that has been developed can manipulate waves like light and sound.
Its design includes a series of hollow square columns set in rows with a slit down one side of the column. The important aspects of the design are the width of the channels created between each row and the cavity inside each column. Each column is engineered to vibrate at different frequencies, depending on the amount of plastic with which it is filled. This vibration affects the speed of the sound wave and interacts with surrounding columns and cavities to control the sound waves.
A computer program was created to establish the behavior of the reflected sound waves. For example, the program can be set to redirect a sound wave coming straight at the material to a 60-degree outgoing angle. The accuracy of this parameter is 96%; previous results were only 60% effective.
An innovative material such as this has many possible applications, ranging from consumer acoustics to medical imaging and more.