Protected: Amy weekly update 8-16-16

This content is password protected. To view it please enter your password below:

Protected: Fwu Tay Weekly Update 8/9/2016

This content is password protected. To view it please enter your password below:

Hosein Weekly Update

Eventually, we find the mechanical properties of our single crystal quartz. We contact the company and they sent us the paper includes all the properties. On their website they just upload Cij and Sij not others. So here is the properties:

tensile strength: 80 perpendicular-110 parallel (MPa); Bending: 90 perpendicular-135 parallel (MPa) .

Once I used the average value of 85 MPa as for \sigma_c, I saw very soon fracture in the sample and the simulation failed. But later when I increased the magnitude of till \sigma_c=300-350 Mpa, the fracture initiated at the time close to the peak of the applied force and capture the full crack propagation through the depth of the specimen.

So at this moment I conclude that either the code has some issues in calculating the correct stress matrix or the experimental data is overestimated.

Robinson Weekly Update

  • Introduction: still working
    • Need to find reference(s) for there being a gradient of strain rates in an impact event
    • still looking for more cases of piezo actuators being used for a mechanical testing device
  • Design Goals: mostly done
    • achieve high signal to noise ratio for small specimens that have low fidelity Kolsky bar signals
    • low compliance loading frame
    • intermediate strain rates
    • compatibility with placement on synchrotron optical tables and around vacuum x-ray tubes
    • portability inside small pelican case for travel on airline
  • Design Decisions: rough draft complete
  • Experimental Procedure: still need to write, but should be straight forward to write
  • Experimental Results: mostly done, convert forces to K_1?
  • Discussion:
    • focusing here mostly on the degree to which design goals were achieved as opposed to material response/phenomena
  • Recommendations: done, changing as other sections are completed
    • frame could be less thick given forces required to fracture small specimens
    • choose a less compliant, less accurate vertical positioning stage. accomplish micron level positioning with an amplified piezo actuator. Currently a compromise was made between accurate positioning and compliance which resulted in a system not very suitable for high forces.
  • Conclusions: done, changing as other sections are completed
    • device was successful in delivering results for e_dot = [10, 40], need better triggering/more set up time to record entire event at e_dot = 100 +

Protected: Fwu Tay weekly update 7/26,2016

This content is password protected. To view it please enter your password below:

Kavan Weekly Update 7/20/16

1. Finalized the single crystal paper and submitted to KT. We are planning to submit the paper by Thursday.
2. Worked with REAP students. We performed 3-point bending test in the Dental School at University of Maryland to measure mechanical properties of the new composites we are making for tooth filling application.
3. Preparing myself for Innovation Engineering 3 hours lecture which is going to be held July 20.

Robinson Weekly Update

1.) Almost done processing data

2.) Not a lot of progress was made last week other than working on the plane. I went to my cousins wedding in Seattle.

Kavan weekly update: July 13, 2016

1. Training high school summer students: took the students to different labs and explained what type of research are done in each lab. We also started working on their research project which is to design new tooth filling materials.
2. Reorganizing my single crystal paper: after receiving KT’s thirst review, we decided to re structure the paper and make it shorter for Nature magazine.

Protected: Fwu Tay weekly update 7/6/2016

This content is password protected. To view it please enter your password below: