Robinson Weekly Update

Aug 9, 2016 | No Comments | By Andrew Robinson

  • 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 +

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