Accession Number : ADA132025

Title :   The Compressive Strength of Carbon Fibre Reinforced Plastics.

Descriptive Note : Technical rept.,

Corporate Author : ROYAL AIRCRAFT ESTABLISHMENT FARNBOROUGH (ENGLAND)

Personal Author(s) : Port,K F

PDF Url : ADA132025

Report Date : Aug 1982

Pagination or Media Count : 51

Abstract : The merits of some alternative test specimens for the measurement of compressive strength of unidirectional carbon fibre reinforced plastics are discussed and it is concluded that whilst the RAE design is close to the optimum some improvements are desirable. Test demonstrated that the present standard RAE specimen is measuring a buckling strength. A modified specimens is suggested which measures a representative compressive strength of the material and this value has been shown to be attainable in the 0 degrees plies of some multi-directional laminates. It has been shown that compressive failure of current unidirectional material involves fibre microbuckling and that a shear fialure is not attainable even at -70 degrees C. The compressive stress-strain response of unidirectional CFRP has been shown to be nonlinear and this is attributed to elastic fibre microinstability which is initiated by initial fibre waviness. A brief experimental investigation has shown that the compressive strength of multidirectional CFRP (0 + or - 45 degrees) does not obey a rule of mixtures when more than 30% 0 degrees plies are present. It is therefore concluded that the compressive strengths of such laminates cannot be calculated from the properties of the constituent plies. (Author)

Descriptors :   *Reinforced plastics, *Carbon fibers, *Compressive properties, *Strength(Mechanics), *Failure(Mechanics), Test and evaluation, Test methods, Unidirectional, Shear strength, Buckling, Modulus of elasticity, Stability, Epoxy resins, Laminates, Microstructure, Fractography, Equations, Mathematical models

Subject Categories : Laminates and Composite Materials
      Test Facilities, Equipment and Methods
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE