Accession Number : ADA266465


Title :   Highly Transient Elastodynamic Crack Growth in a Bimaterial Interface: Higher Order Asymptotic Analysis and Optical Experiments


Corporate Author : CALIFORNIA INST OF TECH PASADENA GRADUATE AERONAUTICAL LABS


Personal Author(s) : Liu, Cheng ; Lambros, John ; Rosakis, Ares J


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a266465.pdf


Report Date : 20 Dec 1992


Pagination or Media Count : 98


Abstract : A higher order asymptotic analysis of the transient deformation field surrounding the tip of a crack running dynamically along a bimaterial interface is presented. An asymptotic methodology is used to reduce the problem to one of the Riemann-Hilbert type. Its solution furnishes displacement potentials which are used to explicitly evaluate the near-tip transient stress field. Crack-tip fields corresponding to crack speeds up to the lower of the two shear wave speeds are investigated. An experimental study of dynamic crack growth in PMMA/ steel interfaces using the optical method of CGS and high speed photography, is also described. Transonic terminal speeds (up to 1.4c sub s(PMMA) and initial accelerations (approx. 10(8)m/secz92)) are reported and discussed. Transient effects are found to be severe and more important than in homogeneous dynamic fracture. For subsonic crack growth, these experiments are used to demonstrate the necessity of employing a fully transient expression in the analysis of optical data to accurately predict the complex dynamic stress intensity factor history.


Descriptors :   *FIBER REINFORCED COMPOSITES , *CRACK PROPAGATION , VELOCITY , INTERFACES , ACCELERATION , OPTICAL DATA , HIGH SPEED PHOTOGRAPHY , TERMINALS , PHOTOGRAPHY , STEEL , DEFORMATION , CRACKS , DISPLACEMENT


Subject Categories : Laminates and Composite Materials
      Mechanics


Distribution Statement : APPROVED FOR PUBLIC RELEASE