Accession Number:

ADA218373

Title:

Dynamic Fracture of Concrete. Part 2

Descriptive Note:

Final rept. 15 Jun 1986-14 Dec 1989

Corporate Author:

WASHINGTON UNIV SEATTLE DEPT OF CIVIL ENGINEERING

Report Date:

1990-02-14

Pagination or Media Count:

143.0

Abstract:

A displacement controlled dynamic test system and instrumentation for dynamic fracture testing of concrete specimens, was developed. Also a hybrid experimental-numerical procedure for evaluating the dynamic fracture data thus generated was developed. The experimental data consisted of the applied load and transient strains in single edge notched, three point bend specimens which were subjected to controlled displacement loading. In addition, moire interferometry data was obtained in three point bend specimens subjected drop weight loading. Also the applied load, transient strains and crack opening displacement were measured in crack-line wedge-loaded, double cantilever beam specimens which were subjected to controlled wedge displacement loading. These test systems and the hybrid analysis were used to determine the strain rate sensitivity of the elastic properties and the fracture process zone of rapidly fracturing concrete specimens. The increase in both tensile and compressive moduli of elasticity and the tensile strength with increasing strain rate were quantified. The fracture process zone decreased in magnitude with increasing strain rate but the tensile strength necessary to propagated the tip of the fracture process zone under a tensile strength criterion increased substantially with the strain rate. The net effect was that dynamic fracture responses of a rapidly propagating crack in concrete resembled that of linear elasto-dynamic fracture mechanics with influence of the fracture process zone decreasing with increasing strain rate of loading.

Subject Categories:

  • Ceramics, Refractories and Glass
  • Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE