Accession Number:

ADA279808

Title:

Dynamic Decohesion of Bimaterials: Experimential Observations and Failure Criteria

Descriptive Note:

Corporate Author:

CALIFORNIA INST OF TECH PASADENA GRADUATE AERONAUTICAL LABS

Personal Author(s):

Report Date:

1994-02-01

Pagination or Media Count:

50.0

Abstract:

Some results of high speed interferometric measurements on dynamically propagating interfacial cracks are presented. PMMASteel bimaterial specimens of the one point bend type are used. They are impact loaded using either a drop weight tower device or a high speed gas gun. This results in two distinct groups of experiments at different loading rates. In all cases very high crack propagation speeds are seen. In gas gun experiments, terminal crack tip speeds of up to 1.5CsPMMA, where CSPMMA is the shear wave speed of PMMA, are measured. In addition, high accelerations 107g, where g is the acceleration of gravity are observed and reported. Theoretically predicted near tip fields are used to extract experimental values of the dynamic complex stress intensity factor histories in each test. Using the fitted histories of the complex stress intensity factor, a dynamic crack growth criterion relating the energy release rate to phase angle and crack tip velocity is proposed and discussed.

Subject Categories:

  • Laminates and Composite Materials
  • Metallurgy and Metallography
  • Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE