Accession Number : ADA306028

Title :   Environmental Effects on Defect Growth in Composite Materials,

Corporate Author : BOEING MILITARY AIRPLANE CO SEATTLE WA

Personal Author(s) : Porter, T. R.

PDF Url : ADA306028

Report Date : JAN 1981

Pagination or Media Count : 406

Abstract : The objective of this program was to derive data for evaluating the effects of moisture and temperature on the integrity of fiber composite components. In particular, the static and cyclic performance of three composite laminates containing flaws was investigated at room temperature and 422K (300 deg F) in wet and dry conditions. The test results evaluate the following for each environmental condition: (a) Effect of defect type and size on static fracture; (b) Influence of compression loadings on fatigue; (c) Description of the effects of static and cyclic loadings on damage accumulation; (d) The effect of preloading on damage growth, static strength, and cyclic load behavior; and (e) The comparison of wet and dry data at room and 422K (300 deg F) temperatures. Static fracture data were obtained for three different composite systems that had been moisture soaked to near the maximum moisture absorption potential. The fracture test data were obtained at room temperature and immediately after the application of an abrupt temperature transient that caused the specimen to attain 422K (3000F). Three different 20-ply layups were tested. Laminate L1 represents general purpose structure, laminate L2 is typical of polar and hoop wound pressure vessels, and laminate L3 is representative of turbine engine fan blades or tubular strut support structure. Half the test specimens were preloaded to 90% of their ultimate static load prior to moisture conditioning. Intermittent nondestructive inspection, including visual and ultrasonic techniques, were used to detect defect growth.

Descriptors :   *COMPOSITE MATERIALS, *ENVIRONMENTAL IMPACT, *DEFECTS(MATERIALS), TEST AND EVALUATION, COMPRESSION, EXPERIMENTAL DATA, ENVIRONMENTS, DAMAGE, NONDESTRUCTIVE TESTING, GROWTH(GENERAL), LAMINATES, STATIC LOADS, FIBER REINFORCED COMPOSITES, FAN BLADES, MOISTURE CONTENT, STRENGTH(MECHANICS), FRACTURE(MECHANICS), CYCLES, ROOM TEMPERATURE, TURBINE BLADES, INSPECTION, LOW LEVEL, TUBULAR STRUCTURES, BEHAVIOR, ABSORPTION, MOISTURE, ACCUMULATION, STATICS, ULTRASONIC TESTS, STRUTS, MOISTUREPROOFING.

Subject Categories : Laminates and Composite Materials

Distribution Statement : APPROVED FOR PUBLIC RELEASE