Accession Number : ADA295115

Title :   Center for Advanced Materials of High Quality Dynamic Performance (Center of Excellence) (Research).

Descriptive Note : Final technical rept. 1 Oct 86-30 Jun 92,

Corporate Author : CALIFORNIA UNIV SAN DIEGO LA JOLLA DEPT OF APPLIED MECHANICS AND ENGINEERING SCIENCES

Personal Author(s) : Nemat-Nasser, Sia

PDF Url : ADA295115

Report Date : 25 MAR 1995

Pagination or Media Count : 62

Abstract : Since October, 1986 the Center for Advanced Materials of High Quality Dynamic Performance has been established at the University of California, San Diego, by the Army Research Office, Durham, as part of DoD's University Research Initiative. This phase of this URI continued to June, 1992 (including a no-cost extension). This multidisclipinary Center focused on a coordinated macroscopic and microscopic experimental and theoretical characterization and constitutive modeling of the mechanical response and failure modes of advanced materials at ultrahigh strain rates. The Center has developed unique state-of-the-art instrumentation for controlled mechanical testing of metals, metal-matrix composites, ceramics, and ceramic composites, over the full range of strain rates from quasi-static to greater than 10 to the 6th/s, and temperatures from -200 deg C to greater than 1000 deg C with complete time-resolved data acquisition systems. Among the Center's major contributions are novel dynamic recovery techniques invented for split Hopkinson bars, normal and oblique plate impact experiments, and laser-induced compression/tension involving pulses of extremely short duration and high amplitude. These are expected Sc impact the nature of future high strain rate testing. This is paralleled by physically-based micromechanical models of high strain rate plastic flow of metals, microcracking, phase transformation, and damage evolution in advanced an their composites. A breakthrough has been made in computational algorithms, which provides a powerful tool for constitutive computational modeling of the nonlinear response and failure modes of ductile materials. (MM)

Descriptors :   *METALS, *COMPOSITE MATERIALS, *METAL MATRIX COMPOSITES, *EXPLOSION EFFECTS, *CERAMIC MATERIALS, TEST AND EVALUATION, COMPRESSION, MATHEMATICAL MODELS, ALGORITHMS, MECHANICAL PROPERTIES, ARMY RESEARCH, DAMAGE, STATE OF THE ART, PHASE TRANSFORMATIONS, IMPACT TESTS, DEFORMATION, SHOCK WAVES, SHOCK(MECHANICS), TEST METHODS, MATRIX MATERIALS, TEST EQUIPMENT, EXPLOSIVES, FRACTURE(MECHANICS), STRAIN RATE, COSTS, LASER APPLICATIONS, NONLINEAR SYSTEMS, TENSION, DATA ACQUISITION, REFRACTORY METALS, COURSES(EDUCATION), DUCTILITY, AMPLITUDE, FAILURE(MECHANICS), DETONATIONS, MICROCRACKING, SPALLATION.

Subject Categories : Ceramics, Refractories and Glass
      Laminates and Composite Materials
      Properties of Metals and Alloys
      Explosions

Distribution Statement : APPROVED FOR PUBLIC RELEASE