Residual strain effects in needle-induced cavitation

Area of Science:

• Materials Science
• Biophysics
• Mechanical Engineering

Background:

• Needle-induced cavitation (NIC) is used to measure soft material properties.
• Current NIC methods often overestimate elastic and fracture properties.
• Residual strain from needle insertion affects NIC accuracy.

Purpose of the Study:

• To develop a new NIC protocol to reduce measurement errors.
• To investigate the impact of residual strain on NIC measurements.
• To enable accurate local property measurements in soft materials.

Main Methods:

• Experimentally demonstrated a needle retraction protocol before pressurization.
• Created a cylindrical, tube-like fracture below the needle tip.
• Verified the critical cavitation pressure equation for the new geometry.
• Used complementary modeling to assess geometric effects.

Main Results:

• Needle retraction significantly reduces the influence of residual strain.
• The modified NIC protocol enables more confident property measurements.
• Complementary modeling indicated minimal effect of geometric changes on critical pressure.

Conclusions:

• Needle retraction is a viable protocol for improving NIC accuracy.
• This method allows for reliable measurement of local elastic and fracture properties.
• The findings are applicable to soft gels and biological tissues.