Study On Thermal And Mechanical Behavior Of Aramid Fiber Composites During Machining

Aramid fiber composite is a kind of advanced fiber enhanced composite materials, with the advantages of high strength, low density, impact resistance and size stability etc., and has been widely used in the field of aerospace industry, military project and the national economy. However, aramid fiber composites is anisotropic, and the low thermal conductivity and strong toughness of aramid fiber furtherly increase the difficulty of its processing, so it is considered to be a typical hard processing material. The typical defects such as burr, delamination, tearing and thermal damage are easy to be produced during the processing of aramid fiber composites. How to obtain high processing quality of aramid fiber composites is an important factor that restricts its application and development.Based on the National Nature Found "The temperature field and stress field modeling of aramid composite ", this research work is used to Study on the cutting mechanism and temperature field distribution of aramid fiber composites.Based on the material properties and the mechanical behavior of drilling process of aramid fiber composite, mechanism of machining defects is explained. With the scribing test method, the scratches during forming process were observed, the failure mechanism of the aramid fiber and the features of defects were analyzed, and the cutting condition was changed to study the defect formation rules. Through the theoretical analysis and experiment of aramid fiber composite material, it is known that the hole defects are easy to be produced under the cutting force and thermal action. In this paper, we use the carbide twist drill, trepanning drill to carry out drilling test research of aramid fiber composites.With temperature above 200 ℃, vitrification phenomenon can be produced in resin matrix, and thermal conductivity of aramid fiber composite is very low, and it is easy to cause burn defects. However, formation of cutting heat and temperature distribution has not been revealed. For the drilling processing, numerical analysis and method of uniform thermal physical parameters were used to establish the cutting temperature field model of aramid fiber composite, and by thermocouple and infrared thermometer method, the temperature field model was validated. Results show that temperature field model and experimental results differ in less than 10%. The temperature field model under different processing conditions were simulated and analyzed. The influence on temperature field by drilling depth, speed and fiber arrangement are studied.The research results revealed the aramid fiber composite defects formation mechanism, and built the temperature field distribution model during drilling process, and the different processing methods of drilling were explored. processing provides the basis in theory and technique. It provided theoretical basis and technical basis for efficient processing of aramid fiber composites.