Application of the Experiment Design Method in Modelling the Temperature Effect on the Behaviour at a Low Velocity Impact Damage of Epoxy Matrix Reinforced with Unidirectional Carbon Fiber Composite

The present study was carried out to evaluate the temperature effect on the mode II interlaminar fracture behaviour of two unidirectional carbon fiber composite materials subject to low velocity impact damage. Before testing, the specimens were exposed at positive and negative temperatures. The delamination crack energy was calculated at the maximum loading point according to the directed beam theory, to the corrected beam theory and to the compliance calibration. Two types of carbon fiber epoxy composite materials were investigated of denominations AS4/8552 and AS4/3501-6. Unidirectional panels of 32 plies were fabricated according to the prepreg manufacturer`s. A thin film of PTFE was introduced between the mid-planes of the panels in order to provide an artificial starter crack of length 60 mm. Of each materials, five specimens were tested at the statically and the dynamical mode II at the temperatures of:-30,-15, 0, 15, 30, 45 and 60°C. From the experimental results, we conclude that the two composites have a similar behaviour, with a slightly effect of a temperature. The experimental design method was used to obtain a mathematical model describing the effect of the temperature on the crack delamination energy. The compliance calibration method gives conservative values of the crack delamination energy.