INFLUENCE OF MECHANICAL TREATMENT AND NEGATIVE TEMPERATURE ON THE STRENGTH OF CARBON FIBER REINFORCED PLASTICS UNDER STATIC BENDING

The results of tests using the three-point bending method to assess the change in the strength of carbon fiber reinforced plastics produced by the milling method using various cutting conditions are presented. The tests were carried out on samples of three series, each of which was made in two sets. The series of samples differ in the applied cutting conditions (frequency of rotation of a cutter at the same feed), and sets differ in the conditions of exposure before testing: at a positive temperature 20±2 °С and at a negative one –50 °C for 60 hours. It has been established that the cutter rotation frequency has practically no effect on the change in bending strength, however, it significantly affects the value of the maximum deflection and the finish of the cut surface. Reducing the speed of the cutter leads to an increase in temperature in the cutting zone, an improvement in the quality of the cut surface and an increase in maximum deflection. The influence of negative temperature leads to an increase in the maximum deflection and a decrease in the bending strength of carbon fiber reinforced plastics