Abstract
The influence of matrix resin on the time and temperature dependence of the transverse tensile strength, interlaminar shear strength and longitudinal compressive strength of unidirectional CFRP was investigated. These tests were respectively conducted at various temperatures and strain rates.
These strengths of CFRP showed remarkable dependence upon time and temperature in the same manner as the tensile strength of matrix resin.
The master curve of these strengths in CFRP could be obtained using their thermorheologically simple properties. The time and temperature shift factors for the fracture behaviors of CFRP were quantitatively in good agreement with that of matrix resin.
The relations between the tensile strength of matrix resin and these strengths of CFRP were uniquely determined by the volume fraction of fibers etc. Without the dependence of time and temperatures.
The estimation method which was proposed in this paper enables us to evaluated :
1) the transverse tensile strength,
2) the interlaminar shear strength, and
3) the longitudinal compressive strength
of unidirectional CFRP at any combination of strain rates and temperatures using :
1) the time - temperature shift factors for matrix resin, and
2) the strength of CFRP on a constant strain rate at several temperatures,
unless the matrix resin degradates. It is suggested that the range to apply this method is in the combination of the strain rate from one figure up its maximum to one figure down its minimum of the tensile tests of matrix resin, and the temperature from 10℃ above its maximum to 10℃ below its minimum of these tests.
