Use of Thermomechanical Analysis in the Design of a Composite System with a Low Coefficient of Longitudinal Thermal Expansion for End Gauges

Abstract

The work presents the possibilities of using the thermomechanical analysis to design composite systems with carbon fibers, which should have a low coefficient of longitudinal thermal expansion will be potentially valuable in the form of calibrated length gauges. ChS Epoxy 520 epoxy resin (hardener T0492) was used as a matrix for composite production. Carbon fibers were tested in the form of short recycled fibers and continuous fibers in roving and fabric. The values of the coefficient of longitudinal thermal expansion of all prepared systems were determined below the glass transition temperature of the polymer matrix in the temperature range of 5º to 40ºC, i.e., in the range suitable for use in technical practice. From the obtained results, it is evident that carbon fibers significantly influence the epoxy matrix behavior. The coefficients of longitudinal thermal expansion of the epoxy resin in this temperature range from 47.6 to 65.2 [10-6 /K], the coefficients of the composite system with recycled carbon fibers with a random arrangement from 38.6 to 47.6 [10-6/K], coefficients of systems with a parallel array of fibers from to 3.4 to 2.7 [10-6/K] for carbon fibers in the form of roving and 4.3 to 2.0 [10-6/K] for carbon fibers in fabric form.