In a breakthrough that redefines the accessibility and safety of non-destructive testing (NDT), a research team from Japan has demonstrated that ordinary bubble wrap can serve as an effective acoustic source for testing pipelines and other structures—without requiring electricity or complex equipment.
The study, published in Measurement on October 8, 2025, was conducted by Professor Naoki Hosoya and Shuichi Yahagi from Tokyo City University, in collaboration with Toshiki Shimizu and Seiya Inadera from the Shibaura Institute of Technology, and Itsuro Kajiwara of Hokkaido University. Their work introduces a power-free acoustic testing system that uses the sharp burst of air from popping bubble wrap to identify internal flaws within pipes with a 2% error margin.
“The team and I sought a simpler solution: a sound source that is small, inexpensive, and safe to operate in almost any setting,” said Professor Hosoya. “Bubble wrap is a small, inexpensive, and mass-produced product that does not require a power supply, so it is useful in the field, such as under construction.”
The researchers discovered that bursting the air pockets produced acoustic frequencies reaching up to 40 kilohertz, a range sufficient for precise ultrasonic or acoustic testing. A simple system—consisting of a bubble wrap sheet, a microphone, and a computer—enabled the detection of internal obstructions within metal pipes. Using wavelet-based signal analysis, the team tracked reflected sound waves and determined the location of embedded objects with remarkable accuracy.
Unlike traditional impulse-based systems that depend on loudspeakers, lasers, or electric sparks, the bubble wrap approach eliminates power requirements and potential safety risks in flammable or confined environments. The system’s simplicity means it can be operated by a single technician with minimal training, making it especially useful for on-site NDT inspections in construction, manufacturing, or infrastructure maintenance.
“This system may be used in NDT to detect foreign objects in pipework on-site, such as in the construction of buildings, because these sound sources have sufficient acoustic performance, such as an almost impulsive, omnidirectional radiation pattern, repeatability, cost-efficiency, portability, and no power supply in practical use, compared to conventional acoustic excitation devices,” explained Professor Hosoya.
By adjusting bubble size and film thickness, the researchers demonstrated the ability to tune the acoustic output for different inspection scenarios, effectively transforming a common packaging material into a customizable diagnostic tool.
The study highlights how innovation in NDT need not depend solely on advanced hardware or high energy systems. Instead, it showcases the potential of low-cost, sustainable, and portable alternatives to traditional acoustic testing devices.
Future research will focus on refining the method’s sensitivity under varying environmental conditions and developing a handheld version suitable for routine field inspections.
What began as a simple curiosity—an ordinary bubble popping sound—has evolved into a practical scientific tool, illustrating how creativity and engineering can merge to transform everyday materials into instruments of precision.
Reference: https://www.eurekalert.org/news-releases/1103357
