Papers by Author: Bing Yan

Abstract: The aim of this article is to analyze the residual stresses field in a TC4 titanium alloy blade by laser shock processing (LSP).LSP is a new surface processing technology, it uses the laser shock wave to act on the surface of the target and form residual compressive stresses field. The ABAQUS software is applied to simulate the LSP of TC4 titanium alloy blade, and the distributions of the residual stresses field are analysed.After single LSP,the maximum value of residual stress on the surface is 309 MPa.The residual stresses on the surface increase first and then decrease.The residual stresses at the depth continue decreasing with the increase of the depth.After multiple LSP,the maximum value of residual stress on the surface is increased and plastically affected depth is increased.

Abstract: For the high speed cutting process of hardened 45 steel (45HRC), a finite element simulation of cutting deformation, cutting force and cutting temperature is finished with the large general finite element software ABAQUS. Through the building of geometry model, material model and heat conduction model, also the determination of boundary conditions, separation rule and friction condition, a thermal mechanical coupling finite element model of high speed cutting for hardened 45 steel is built. The serrated chip, cutting force and cutting temperature can be predicted. The comparison of experiment and simulation shows the validity of the model. The influence of cutting parameters on cutting process is investigated by the simulation under different cutting depthes and rake angles. The results show that as the increase of rake angle, the segment degree, cutting force and cutting temperature decrease. But the segment degree, also the cutting force and cutting temperature increase with the increase of cutting depth. This study is useful for the selection of cutting parameters of hardened steel.

Abstract: The cutting tool geometry and cutting parameters have a great impact on cutting force, while cutting force is an important factor which affecting the tool life. High speed cutting experiments have shown that when slight axial depth of cut is adopted, rake angle effect on main cutting force significantly. When cutting aluminum alloy, the roughness of machined surface decrease with increasing tool rake angle. The axial depth of cut does not have a big influence on machined surface ’s roughness.

Abstract: A finite element simulation study of cutting process and whole part deformation of a large thin-wall aluminum alloy part used in aerospace is carried out by ABAQUS. The geometry model, material model and heat conduction model are built. The friction conditions and boundary constraints are determined. The whole process of chip generation is simulated and the distribution of strain, stress, cutting temperature and are given. The chip formation and the cutting force are also predicted. Based on the prediction results, the deformation of whole part is predicted. This study establishes the foundation of selection and optimization of cutting parameters and deformation compensation for this kind of large thin-wall parts.

Abstract: In this paper, some high speed cutting experiments of hardened 45 steel are carried out. The effects of cutting parameters on the width and space of adiabatic shear band, the frequency and degree of sawtooth are investigated by metallographic observation and theoretical calculation. The results show that the space of adiabatic shear band decreases with the increase of cutting speed and rake angle, but increases with the increase of cutting depth. The width of adiabatic shear band decreases with the increase of cutting speed and cutting depth, however, increases with the increase of rake angle. The frequency of sawtooth increases with the increases of cutting speed, decreases with the increase of rake angle, and has no obvious relationship with cutting depth. The degree of sawtooth increases with the increase of cutting speed and cutting depth, but decreases with the increase of rake angle.

Abstract: Orthogonal cutting experiments of hardness AISI1045 steel( HRC45) are performed. The change of chip formation and cutting force with cutting conditions are investigated through metallurgical observation, and the critical cutting speed of adiabatic shear of AISI1045 steel at different cutting depths and rake angles are given. In addition, the saw-frequency and space length of serrated chip and the influence of serrated chip on cutting force are also studied. The critical cutting speed decreases with the increase of cutting depth, but increases with the increase of rake angle. The saw-frequency of serrated chip is found to be independent of the cutting depth, and increases with the increase of cutting speed and rake angle. The cutting force decreases with the increase of cutting speed and rake angle, but increases with the increase of cutting depth, and there isn’t a sudden change of cutting force at the onset of adiabatic shear.

Abstract: In this paper, a novel precision press is proposed, which is to combine the motion of a large constant speed motor with a small servomotor via a two-DOF mechanism, where, the constant speed motor provides main torque and motion requirements, while the servomotor contributes to modulations on this motion. The forward kinematic optimal design, electromechanical system dynamics modeling and simulation of this new mechanical press system have been presented here. The simple analysis of theoretical feasibility of the hybrid-driven press is investigated.

Abstract: Orthogonal cutting experiments of Fe-36Ni invar alloy are performed. The change of chip morphology with cutting conditions are investigated through metallurgical observation, and the critical cutting speed of adiabatic shear for Fe-36Ni invar alloy at different cutting depths and rake angles are given. In addition, the characteristic of chip deformation before the occurrence of adiabatic shear is also analyzed. The results show that the critical cutting speed decreases with the increase of cutting depth and hardness, but increases with the increase of rake angle. The deformation coefficient tends to a constant value with the increase of cutting speed.

Abstract: The development of chip morphology, critical cutting condition of adiabatic shear during serrated chip formation and cutting forces were observed and measured by high speed turning experiment for 30CrNi3MoV hardened steel. Results show that the cutting speed and rake angle are leading factors to influence chip morphology and cutting forces. With the increase of cutting speed, the continuous band chip transforms into serrated chip at a certain critical value. As the rake angle is changed from positive to negative, the critical cutting speed of adiabatic shear significantly decreases, the cutting forces abruptly reduces when the serrated chip forms. The results from predicting critical cutting speed using the critical cutting condition criterion of adiabatic shear in metal cutting process show that the leading reason of serrated chip formation is that the adiabatic shear fracture repeatedly occurs in the primary shear zone.