Study Of Cutting Experiment And Simulation Of Carbon Fiber Reinforced Composites

In recent decades，with the development of science and technology carbon fiberreinforced composite materials are increasingly in demand for various industries，suchas aeronautics，astronautic，vehicle，shipbuilding，civil and et al. Using compositematerials can lighten the weight of structural，the capacity of resist damage improvedgreatly. However， owing to the special structure of composite materials, thedelamination, crack and burr appear easily during machining process, the cuttingprecision is influenced and the quality and productivity is appeared. So the research ofmechanism of cutting composite material has become an urgent problem. In1960s themechanics of composite materials developed quickly, the property of composites both ofmacroscopic and microscopic has formation a mature system to supply researchplatform to analysis and study the mechanical properties. Composite materialsmachining methods can be classified into conventional processing and unconventionalprocessing, in conventional processing, cutting is the main way of processing. In present,the study of cutting composite materials mainly focus on discussing and analysis aboutcutting force, processing surface quality, fiber breaking, the matrix damage, matrixdamage evolution, subsurface damage evolution still needs further studies.In this paper, with the theory of finite element and experiments to study the cuttingmechanism of carbon fiber reinforced composite, model of conventional cutting andultrasonic vibration cutting, using the finite element simulation software Abaqus toestablish and analyze the cutting model. Respectively study of cutting mechanism basedon conventional cutting and ultrasonic vibration cutting model. Design the orthogonalexperimental of carbon fiber reinforced composite, the results of experiment arecompared with the ones of finite element numerical analysis. The research has got someresearch as follows:(1) Through design the orthogonal experimental of carbon fiber reinforcedcomposite, the cutting force rapid growth based on fiber orientation increase, but thethrust is not increase with the fiber orientation, when fiber orientation is45othe thrustforce reach the maximum. The changing law of chip morphology and the machiningsurface quality are obtained by different fiber orientation, find that as the fiberorientation change the chip morphology different, when fiber orientation is0othe quality of machining surface is well, when fiber orientation is45othe machining surface hascrack and burr appear, when fiber orientation is90othere are pits and crack appear, andthe crack orientation parallels with fiber orientation.(2) Combine with Hashin Damage failure model, through define ultimate stress tosimulate the failure mode of Uni-directional carbon fiber reinforced composite duringmachining. The reasonability was validated by comparison cutting force betweensimulation results and experimental data of cutting force. From the simulation results,fiber orientation is the main factors that influence the value of cutting force, andinfluence the matrix damage, the matrix damage evolution orientation substantiallyparallel to the fiber orientation, and the sub-surface damage value increases with theincrease of fiber orientation angle.(3) Establish the simulation model of ultrasonic vibration cutting and research thecutting mechanism of carbon fiber reinforced composite, compared with conventionalcutting the scope of matrix damage and the depth of sub-surface damage decreases. Thecutting process under different vibration amplitude and frequency are carried out, thestudy found that the value of cutting force decreases with the increasing of amplitudeand frequency, the region of matrix damage and matrix damage evolution also decreaseswith the increasing of amplitude and frequency.