A device for studying fluid-induced cracks under mixed-mode loading conditions using x-ray tomography

Area of Science:

• Materials Science
• Soft Matter Physics
• Mechanical Engineering

Background:

• Understanding fracture mechanics in soft materials is crucial for applications in biomaterials and soft robotics.
• Existing methods often lack the resolution or non-invasive capabilities to fully characterize complex fracture behaviors.

Purpose of the Study:

• To introduce a novel instrument for investigating fluid-induced fractures in soft materials under mixed-mode loading (tension and shear).
• To enable non-invasive, 3D characterization of crack geometries using X-ray tomography.
• To demonstrate the instrument's utility in analyzing crack-front segmentation in hydrogels.

Main Methods:

• Development of a specialized testing instrument equipped with force, torque, and fluid pressure sensors.
• Integration of the instrument with X-ray tomography for in-situ 3D imaging.
• Experimental study on hydrogels subjected to controlled air pressure and combined tensile/shear stress.

Main Results:

• Successful demonstration of the instrument's capability to apply mixed-mode loading conditions to soft materials.
• Acquisition of high-resolution, 3D crack geometry data using X-ray tomography.
• Detailed analysis of crack-front segmentation under fluid pressure and mechanical stress.

Conclusions:

• The developed instrument provides a powerful tool for studying complex fracture phenomena in soft materials.
• Non-invasive 3D imaging facilitates a deeper understanding of crack propagation mechanisms.
• The findings offer insights into the mechanical behavior of hydrogels under mixed loading conditions.