Simulation of the processes of drilling polymer composite blanks using digital twins

Abstract

Polycrystalline composite materials made of carbon fibre reinforced plastics have more and more widespread application in mechanical engineering and become the main material for the production of modern types of high-speed transport. Thus, their share has already reached 35–45 % in the structural design of passenger aircrafts. However, the technology of machining surfaces of parts made of these materials, in particular, holes, is characterized by insufficient knowledge, the absence of regulatory standards for cutting modes, and is most often based on the production experience of enterprises. When changing the processing conditions and the material, the pre-production engineering duration causes a significant increase in the cost of manufacturing parts due to the need for experimental selection of the cutting mode rational elements. To exclude the empirical selection of rational elements of the machining equipment cutting mode, the authors considered the possibility of using digital twins, for studying the processes of drilling holes in the blanks made of composite materials. The authors included those with the ultrasonic field energy introduction into the new surface shaping zone (to improve the processing quality and productivity). When modelling, the LS-DYNA program was used. The authors prepared the models and processed the results using the LS-PrePost 4.8 program. During the study, an explicit modelling method was used with preliminary validation and calibration of the results of tests of composites. The authors carried out calibration on test operations of tension, three-point bending, and interlaminar shear of the VKU-39 polymer composite material based on carbon fibres (carbon fibre reinforced plastic) widely used in domestic engineering. The developed finite element computer models allow simulating drilling procedures without carrying out rather complicated and expensive field tests. As a result of modelling, a simulation file was obtained, which reflects the process of drilling holes in a polymer composite material blank, as close as possible to the real-life situation with chip removal.