Dynamic Fracture Under Plane Wave Loading.

Abstract

A new plate impact experiment is described to study dynamic fracture processes that occur under sub-microsecond loading. The experiment is designed to make the measurements amenable to interpretation within the framework of fracture mechanics. A disc containing a mid-plane, pre-fatigued, edge crack that has been propagated halfway across the diameter is impacted by a thin flyer plate of the same material. A comprehensive pulse propagates through the specimen and reflects from the rear surface as a step, tensile pulse with a duration of 1 microsecond. This plane wave loads the crack and caused initiation and propagation of the crack. The motion of the rear surface is monitored during this event using a laser interferometer system. The location of the crack front is mapped before and after the experiment using a focussed ultrasonic transducer. Experiments have been conducted on a hardened 4340 VAR steel, at temperatures ranging from room temperature to - 100 C. Crack advance increases monotonically with increasing impact velocity and with decreasing temperature. A finite difference method is used for numerical simulation of the experiments.

Document Details

Document Type
Technical Report
Publication Date
Dec 01, 1986
Accession Number
ADA178594

Entities

People

  • G. Ravichandran
  • R. J. Clifton

Organizations

  • Brown University

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Continuum Mechanics
  • Diameters
  • Fracture (Mechanics)
  • Interferometers
  • Materials
  • Measurement
  • Mechanics
  • Microsecond Time
  • Physics
  • Plane Waves
  • Simulations
  • Transducers
  • Waves

Fields of Study

  • Physics

Readers

  • Combustion Dynamics and Shock Wave Physics.
  • Materials Science (Mechanical Engineering).

Technology Areas

  • Directed Energy