The Compressive Strength of Carbon Fibre Reinforced Plastics.
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)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1982
- Accession Number
- ADA132025
Entities
People
- K. F. Port
Organizations
- Royal Aircraft Establishment