Engineering news
Researchers from Virginia Tech university in the US are placing their new omnidirectional piezoelectric materials in rings, insoles and boxing gloves to monitor forces and power electronics – but they claimed that could just be the tip of the iceberg, with potential applications in robotics and smart infrastructure.
Previous piezoelectric materials – substances that convert mechanical stress and strain into electrical energy – came in defined shapes and were made of brittle crystal and ceramic. To improve the desirable properties and apply them more widely, the researchers developed a 3D printing method to produce materials that are not restricted by shape or size.
Led by mechanical engineer Xiaoyu ‘Rayne’ Zheng, the team created a model that allowed them to manipulate and design arbitrary piezoelectric constants, resulting in the material generating electric charge in response to incoming forces and vibrations from any direction.
The materials were printed from a synthetic, highly sensitive piezoelectric ink that was ‘sculpted’ using ultraviolet light in a high-resolution digital light 3D printer.
“We can tailor the architecture to make them more flexible and use them, for instance, as energy-harvesting devices, wrapping them around any arbitrary curvature,” Zheng said. “We can make them thick, and light, stiff or energy-absorbing.”
Mechanical engineer Shashank Priya said: “The ability to achieve the desired mechanical, electrical and thermal properties will significantly reduce the time and effort needed to develop practical materials.”
The team has demonstrated smart materials wrapped around curved surfaces and worn on hands and fingers to harvest mechanical energy, but they said the applications “go well beyond” wearables and consumer electronics. Zheng said the technology could be useful in robotics, tactile sensing and intelligent infrastructure. Entire structures could be made of piezoelectric material, the team said, designed to detect and locate impacts or vibrations.
“Traditionally, if you wanted to monitor the internal strength of a structure, you would need to have a lot of individual sensors placed all over the structure, each with a number of leads and connectors," said the research paper's first author, Huachen Cui. “Here, the structure itself is the sensor – it can monitor itself."
The research was published in Nature Materials.
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