Accession Number : ADA118084

Title :   Effect of Load History on Fatigue Life.

Descriptive Note : Final technical rept. 1 Jan 80-30 Apr 81 on Task 2,

Corporate Author : LOCKHEED-CALIFORNIA CO BURBANK RYE CANYON RESEARCH LAB

Personal Author(s) : Ryder,J T ; Lauraitis,K N

PDF Url : ADA118084

Report Date : Dec 1981

Pagination or Media Count : 281

Abstract : The primary objectives of this program were to: (1) investigate the effects of mechanical load history on the response of laminated graphite/epoxy composites; and (2) to analyze the results in a manner such that an expanded foundation is laid for formulating cumulative damage concepts. The research investigation was divided into three tasks: Task I, Diagnostic Experimentation; Task II, Effect of Loading Parameters; and Task III, Data Analysis and Reporting. In Task I, the laminate of interest was selected as a quasi-isotropic layup of T300/5208 graphite/epoxy material. The unidirectional properties of the material were characterized at room temperature and at 82.2 C (180 F) in both an as-received and a high moisture content condition. Moisture absorption and thermal expansion properties of the laminate were obtained. Static tension and compression properties of the quasi-isotropic laminate as well as those for unidirectional laminates were determined. During Task II, different types of mechanical load histories were applied, at room temperature, to coupons of the selected quasi-isotropic laminate. Distributions of either monotonic strength or cyclic life, which ever was appropriate, were obtained for the various applied load histories.

Descriptors :   *Composite materials, *Graphite, *Epoxy resins, *Fatigue life, Laminates, Diagnosis(General), Loads(Forces), Data processing, Nondestructive testing, Mechanical properties, Moisture content, Unidirectional, Test methods

Subject Categories : Laminates and Composite Materials
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE