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Analytical Instrumentation Methods Materials
Testing the Strength of Soft Materials
WARF: P220230US01

Inventors: Melih Eriten, Corinne Henak

The Wisconsin Alumni Research Foundation is seeking commercial partners interested in developing a method to assess the failure properties of soft materials. The technique uses acoustic emissions to create a high-throughput, minimally invasive way to test materials in real time.
Overview
Soft materials are everywhere. In many applications, valuable information about the strength of these materials enables more precise control in everything from cutting and processing soft foods to designing new medical devices or assessing tissue properties for diagnostic applications. Current testing methods, such as 3- or 4-point bending, puncture/indentation and wire cutting, require lots of material and are destructive. An efficient, minimally invasive technique that works in real time is needed.

In hard materials like ceramics, concrete and composites, acoustic emissions (AE) testing detects the release of elastic energy in fractured materials and provides qualitative and quantitative data on crack nucleation, crack propagation, plastic deformation and dislocation motion. It has been used in applications like seismic and structural health monitoring. AE testing has yet to be widely studied in soft materials.
The Invention

UW-Madison researchers have developed a method for testing the mechanical and failure properties of soft materials using a non-contact, portable vibrometer that measures acoustic emissions. The team has established a direct link between the characteristics of emissions from failure in the materials and their properties. AE signals include maximum amplitude, frequency content, duration, rise time and energy. Vibrometers can measure the AE of incredibly small fractures – on the order of several micrometers – at multiple locations with high frequency, making them ideal for monitoring soft materials in real time.


This technique has multiple medical applications, including measuring tissue properties during surgeries, biopsies and other procedures. Tissue stiffness has known correlations for different types of cancerous and non-cancerous tissues. The device can be embedded into cutting instruments such as scalpels, scissors, blades, needles, etc. to estimate tissue stiffness and failure resistance in real time. The method also has applications in biomanufacturing and the food industry, including optimizing cutting parameters for speed and waste reduction.

Applications
  • Measures and monitors the strength and durability of soft materials
Key Benefits
  • No comparable method is currently available on the market
  • Provides comprehensive data on the failure threshold and load-bearing capacity of soft materials in real time
  • Can continuously monitor multiple, microscopic fractures at high speeds (~100 kHz)
  • Non-contact measurements of acoustic waves allow for affordable, minimally invasive, high throughput monitoring
Stage of Development
The team tested their method using gelatin-based hydrogels with different concentrations. They introduced fractures of various sizes into the gels using different degrees of force. The AE from these fractures were measured using a non-contact laser vibrometer. Similar to hard materials, the energy of AE in soft materials was found to increase as fracture energy increased. From these data, they computed the failure properties of the materials.
Additional Information
For More Information About the Inventors
Tech Fields
For current licensing status, please contact Michael Carey at [javascript protected email address] or 608-960-9867

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