1) Fracture Marking

Challenge

Conventional fracture marking methods  (High R-ratio blocks) do not work well with metals like Ti, nor at near threshold conditions.

Innovation

Local Heat Tint using electric pulse promises good observability in heat- tintable materials all the way down to threshold levels.

2) Local Heat Tint Technique

Analogous to deformation, we can express the singular voltage field in terms of a scalar multiplier.

4) Proof of Concept: High Amp Pulse in Ti Foil

Digitally enhanced tint colors from oxide layer film.

Tint radius 0.14 inch—100x larger than required to mark.

Asymptotic Electrothermal solution developed to enable temperature control.

5) Crack-tip Temperature Control

•Franc3D/Mode III handbook solutions used to obtain KE solution.

•Steady-state thermal solution depends on external boundary conditions.

•Local Transient thermal solution insensitive to external boundary conditions.

•High-Amp transient electric pulses renders local thermal response largely geometry independent for given (KE, tpulse), and enables sharp tint lines.

•KE and transient thermal solutions built-in to FractureLab software to enable precision crack tip heating/local tinting for common specimens.

6) System Architecture & Schematics

8) The Takeaways

The

•Series 5000 for Premium Marking Capability•Custom Configuration for Special Application
•Fully supported with Consulting Services 

Possible Applications

•Crack growth threshold testing.

•Study of microstructural fracture mechanism.