Gap Test Calibrations and Their Scaling

Abstract

Common tests for measuring the threshold for shock initiation are the NOL large scale gap test (LSGT) with a 50.8-mm diameter donor/gap and the expanded large scale gap test (ELSGT) with a 95.3-mm diameter donor/gap. Despite the same specifications for the explosive donor and polymethyl methacrylate (PMMA) gap in both tests, calibration of shock pressure in the gap versus distance from the donor scales by a factor of 1.75, not the 1.875 difference in their sizes. Recently reported model calculations suggest that the scaling discrepancy results from the viscoelastic properties of PMMA in combination with different methods for obtaining shock pressure. This is supported by the consistent scaling of these donors when calibrated in water-filled aquariums. Calibrations and their scaling are compared for other donors with PMMA gaps and for various donors in water.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 2012
Accession Number
ADA570170

Entities

People

  • Harold W. Sandusky

Organizations

  • Naval Surface Warfare Center Indian Head Division

Tags

Communities of Interest

  • Counter IED

DTIC Thesaurus Topics

  • Attenuation
  • Calibration
  • Composite Materials
  • Diameters
  • Energetic Materials
  • Explosives
  • Geometry
  • Materials
  • Measurement
  • Methacrylates
  • Pentolite
  • Polymethyl Methacrylate
  • Specifications
  • Standards
  • Streak Cameras
  • Subatomic Particles
  • Surface Warfare

Readers

  • Aerospace Test and Evaluation
  • Combustion Dynamics and Shock Wave Physics.