In this paper, a new approach for evaluating the cryogenic machining process of the carbon nanotube reinforced aluminum matrix composites is developed based on finite element method. Finite element modeling in commercial code ABAQUS/Explicit was used to simulate high-speed machining of carbon nanotube reinforced composites under dry and cryogenic conditions, where different parameters (carbon nanotubes loading and the cutting speed) were investigated. The matrix phases are given a Johnson–Cook failure criterion. For considering more realistic assumptions, mechanical and thermal properties of the materials are assumed as a function of temperature. Results shown that at the cutting velocity of 60 m/s, cryogenic cooling has caused decrease of workpiece plastic strain by 12% in comparison with the dry cooling. The model can be used to study the effect of weight fraction, orientation, and length of the carbon nanotubes on the manufacturing of the nanocomposites.

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In this study, the large amplitude vibration and the stability of embedded carbon nanotubes (CNTs) conveying viscous fluid are analyzed. The effects of small-scale are presented into the model based on the nonlocal elasticity theory by changes in the fluid properties. Moreover, the viscosity effect is modeled by Rayleigh's dissipation function. After separating the time part of the governing equation, a modified method based on He's variational iteration method is proposed, the time response, and the complex nonlinear frequencies are obtained. Then, the effects of the geometric parameters, the velocity and the viscosity of the flowing fluid and small-scale effects are investigated on the nonlinear vibration behavior of CNTs. Results reveal that small-scale effects reduce the critical flow velocity. The viscosity effect appears as the nonlinearity due to large vibration amplitude increases, which cause reduction in both nonlinear frequencies and critical flow velocities.

Accuracy of a five-axis CNC machine tool is affected by a vast number of error sources. This paper investigates volumetric error modeling and its compensation to the basis for creation of new tool path for improvement of work pieces accuracy. The volumetric error model of a five-axis machine tool with the configuration RTTTR (tilting head B-axis and rotary table in work piece side A΄) was set up taking into consideration rigid body kinematics and homogeneous transformation matrix, in which 37 error components are included. Volumetric error comprises 37 error components that can separately reduce geometrical and dimensional accuracy of work pieces. The machining accuracy of work piece is guaranteed due to the position of the cutting tool center point (TCP) relative to the work piece. The cutting tool is deviated from its ideal position relative to the work piece and machining error is experienced. For compensation process detection of the present tool path and analysis of the RTTTR fiveaxis CNC machine tools geometrical error, translating current position of component to compensated positions using the Kinematics error model, converting newly created component to new tool paths using the compensation algorithms and finally editing old G-codes using G-code generator algorithm have been employed.