Experimental study on the influence of different laying methods on the thermomechanical properties of carbon fiber/epoxy hybrid composite

Abstract

The thermomechanical tests were carried out on the composite materials under different laying methods (thickness and angle) based on cone calorimetry, high temperature oxygen index method, vertical/horizontal combustion method and high temperature mechanics test method. The results show that the peak values of ignition time and heat release rate of carbon fiber/epoxy composite increase with the increase of the thickness of the layer. Time to peak is advanced. The mass loss rate increases. The high temperature oxygen index of the material increases. The vertical/horizontal combustion rate decreases. Time to reach peak production rate of CO/CO 2 is shortened. The peak value of smoke production rate decrease. The time needed to reach the peak of smoke production rate is longer. Total smoke emission increased. The flue gas release process lasts longer. The function model of mass loss rate and heat radiation intensity is obtained. The vaporization heat of carbon fiber/ epoxy composite with different thickness was calculated. The effects of laying angle on oxygen index, smoke production rate and CO/CO 2 parameters are not obvious. When the laying angle [0°/90°] is the same as the fire spreading direction, the vertical/horizontal burning speed is higher. The difference between the laying angle [±45°] and the flame spreading direction is beneficial to the smoke emission from the bottom layer. Total smoke emission increased. The mechanical properties of materials at high temperature are related to the laying angle. When the temperature is 150°C, the mechanical properties of the material are lower than that of 25°C. The fitting functions of high temperature mechanics in the range of 25°C−150°C were obtained. It can predict the mechanical properties of materials at different temperature points in this temperature range. IntrodutionCarbon fiber/epoxy composite has the advantages of light weight and high strength [1]. It has excellent thermal stability and good fatigue resistance. It has strong designability [2, 3]. Carbon fiber/epoxy composite is the main structural material in the field of aviation [4,5]. It is more and more applied to the main components, loadbearing structures, secondary structural materials and structural components of aerospace vehicles [6,7]. Especially in the field of general aviation, the amount of composite materials used in many small airplanes is even more than 90% of the structural weight [8]. However, when the epoxy matrix in the carbon fiber/epoxy composite is heated, it will decompose the combustible gas [9][10][11]. It will cause fire to the aircraft. Laying design is an important part of the structural design of carbon fiber/epoxy composite. The strength, rigidity and stability of the material are closely related to the laying method [12]. The important content of laying design is to define the thickness and angle of laying [13]. The change of the laying method has an impact on the performance of OPEN ACCESS RECEIVED