Serpentine Transmitted Bar

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[[Intermediate Strain Rate Bar| < Intermediate Strain Rate Bar]] <br>
 
[[Intermediate Strain Rate Bar| < Intermediate Strain Rate Bar]] <br>
  
  When an intermediate strain rate test is performed, the stress experienced in the test specimen is transmitted to the serpentine bar in the form of a stress wave. This stress wave travels the length of the transmitted bar and is measured by a strain gage. Challenges arise with gathering data via the strain gage. The stress wave created when the test is initiated hits the end of the transmitted bar and is reflected back to the strain gage before the specimen fails. Therefore, the transmitted bar needs to be as long enough to avoid seeing the reflected wave before the specimen fails. Many national labs and research facilities do not have the footprint available to house a long bar. The original patented design of the serpentine bar features three concentric tubes welded together at the ends. This design allows for the stress wave to propagate through all of the tubes before it reflects back. This allows for the serpentine bar to have an effective length much greater than its physical length thereby being more efficient for its footprint.
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When an intermediate strain rate test is performed, the stress experienced in the test specimen is transmitted to the serpentine bar in the form of a stress wave. This stress wave travels the length of the transmitted bar and is measured by a strain gage. Challenges arise with gathering data via the strain gage. The stress wave created when the test is initiated hits the end of the transmitted bar and is reflected back to the strain gage before the specimen fails. Therefore, the transmitted bar needs to be as long enough to avoid seeing the reflected wave before the specimen fails. Many national labs and research facilities do not have the footprint available to house a long bar. The original patented design of the serpentine bar features three concentric tubes welded together at the ends. This design allows for the stress wave to propagate through all of the tubes before it reflects back. This allows for the serpentine bar to have an effective length much greater than its physical length thereby being more efficient for its footprint.
  
 
==References==
 
==References==
 
<references/>
 
<references/>

Revision as of 01:14, 18 April 2019

Schematic of coaxially embedded serpentine bar. [1]

< Intermediate Strain Rate Bar

When an intermediate strain rate test is performed, the stress experienced in the test specimen is transmitted to the serpentine bar in the form of a stress wave. This stress wave travels the length of the transmitted bar and is measured by a strain gage. Challenges arise with gathering data via the strain gage. The stress wave created when the test is initiated hits the end of the transmitted bar and is reflected back to the strain gage before the specimen fails. Therefore, the transmitted bar needs to be as long enough to avoid seeing the reflected wave before the specimen fails. Many national labs and research facilities do not have the footprint available to house a long bar. The original patented design of the serpentine bar features three concentric tubes welded together at the ends. This design allows for the stress wave to propagate through all of the tubes before it reflects back. This allows for the serpentine bar to have an effective length much greater than its physical length thereby being more efficient for its footprint.

References

  1. Whittington, W. R., Oppedal A. L., Francis, D. K., Horstemeyer, M. F., A novel ISR testing device: The serpentine transmitted bar, International Journal of Impact Engineering, 2015, vol. 81, pp. 1-7.
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