Accession Number : ADA305188

Title :   Residual Strength Degradation for Advanced Composites.

Descriptive Note : Interim quarterly rept. 1 Feb-30 Apr 78,

Corporate Author : LOCKHEED-CALIFORNIA CO BURBANK

Personal Author(s) : Pettit, D. E.

PDF Url : ADA305188

Report Date : 05 MAY 1978

Pagination or Media Count : 30

Abstract : Associated with the difficulties in defining the exact nature of damage and its effect on service life is the added problem of developing adequate nondestructive inspection methods to detect the damage and analysis methods to define its severity. The development of methods of defining, detecting, evaluating, and analyzing these types of damage in a framework consistent with current durability and damage tolerance requirements is the problem area addressed in the current program. Specifically, the objeftives of the current program are (1) to develop a statistically valid data base defining the growth behavior of damage regions in graphite/epoxy composite material, (2) develop an analysis methodology that is capable of predicting (a) the growth of damage zones under fatigue loading and (b) the resulting residual strength of the structure with a given fatigue induced damage zone size and configuration, (3) determine the mechanisms of fatigue induced damage formation and propagation, and (4) define the threshold damage sizes which will not propagate and the associated damage zone formation criteria. (AN)

Descriptors :   *RESIDUAL STRESS, *GRAPHITE EPOXY COMPOSITES, VELOCITY, DATA BASES, MATHEMATICAL MODELS, LOAD DISTRIBUTION, TENSILE STRENGTH, NONDESTRUCTIVE TESTING, LIFE EXPECTANCY(SERVICE LIFE), FATIGUE LIFE, DEGRADATION, STRESS ANALYSIS, STATIC LOADS, STRUCTURAL ANALYSIS, DAMAGE ASSESSMENT, FIBER REINFORCED COMPOSITES, MATRIX MATERIALS, IMPACT STRENGTH, CRACK PROPAGATION, FLEXURAL STRENGTH, TENSION, EPOXY LAMINATES, BUCKLING, DROP TESTS, QUALITY CONTROL, TOLERANCES(MECHANICS), AIRCRAFT PANELS, FATIGUE TESTS(MECHANICS), ULTRASONIC TESTS, SHEAR STRENGTH, STRUCTURAL INTEGRITY.

Subject Categories : Laminates and Composite Materials
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE