A device to fracture soft solids at high speeds

Matt P. Milner, Shelby B. Hutchens

Research output: Contribution to journalArticle

Abstract

We describe the development of a device for high-rate, pneumatic fracture. The Small-scale Ballistic Cavitation (SBC) device uses a high pressure reservoir to generate cavities within ultrasoft solids (moduli < 100 kPa) in bursts as short as 5 ms. Flow accelerates through a needle embedded within a soft solid, reaching the speed of sound at the tip before delivery to the sample. The energy density of the air pulse matches that of handgun projectiles, enabling ballistic-like temporary cavities, but on a benchtop scale. We validate the device using mass transfer measurements and find good agreement without the use of fit parameters between experiments and theory at the required operational pressures ranging from ∼30 to 160 atm. Independent control of pressure, needle diameter, and valve cycle time provides flexibility in experimental control variables (e.g., energy density, rate) that is not present in other ultrasoft solid cavitation techniques. We demonstrate the device's experimental flexibility via the application of constant energy density with variable loading rate conditions that illustrate the importance of rate on fracture morphology in soft solids.

Original languageEnglish (US)
Pages (from-to)69-75
Number of pages7
JournalExtreme Mechanics Letters
Volume28
DOIs
StatePublished - Apr 2019

Keywords

  • Ballistic
  • Cavitation
  • Fracture
  • High rate
  • Soft materials

ASJC Scopus subject areas

  • Bioengineering
  • Chemical Engineering (miscellaneous)
  • Engineering (miscellaneous)
  • Mechanics of Materials
  • Mechanical Engineering

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