1.) Behind on schedule for data analysis (and writing) by 2 weeks

• Finally got the code again working late last week so analysis of the next 5 tests should go fast
• crack velocities peak at 1200 m/s, and mostly reside in the 100’s of m/s
• force sensor seems to have an inherent response time of ~5 µs
• force curves seem to have a second plateau after load drop
  • need to check if this is an artifact from the force sensor or genuinely linked to some fracture phenomena where the crack arrests temporarily

2.) Need to think harder about converting reaction force readout to stress intensity factor at the notch tip and comparing time till K=K_1c to time of failure. How far do I go down the road of quartz specific analysis as opposed to design of apparatus focus?

3.) Rough draft of introduction is nearing submission for first edit. All other sections are largely contingent on data analysis although introduction is mildly contingent on answer to #2.

I am working with Andrew Leong to derive more experimental results which can be adopted to validate our numerical simulations.

In addition, I am still working on single crystal quartz simulations. We need more accurate fracture properties. I have searched in the literature but cannot find anyone who talked about the mode II fracture propagation in those materials.

I also started studying some papers about physical-based damage model, namely, Paliwal and Ramesh 2008 and Daphalapurkar et al 2011.

I am working on the simulation of dynamic fracture in single crystal quartz specimen. Anisotropiy property is added to the code. In addition, I am still working on my research statement but it is at the end of process. I will give you the daft on this Monday.

I am trying to better understand the physics and mechanisms incorporated in dynamic fracture. I found sort of old but really interesting papers (a series of 4 papers) from Prof. Ravi-Chandar about an experimental investigation into dynamic fracture. In addition, today I am going to present our recent results about dynamic 3-point bending test on Boron carbide.

A draft of report in association with my contribution in DTRA was given to Prof. Hufnagle.

1- I have obtained some preliminary results for fracture of Boron carbide sample under dynamic 3-point bending test. To provide a comprehensive comparison with experimental data, more numerical examples are needed. I am carrying out new numerical tests with varying fracture toughness, modulus of rupture (MOR) and also density.  I want to figure out how those parameters effect the max. crack propagation speed.

2- I need to write a report for Prof. Hufnagel by June 24th. A draft will be given to Nitin by next Monday June 20th.