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Feasibility study of high feed axial ultrasonic vibration turning of Ti6Al4V

Li Kaile, Shao Wen, Tang Jinyuan, Huang Weiwei, Li Xin

Archives of Civil and Mechanical Engineering

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2024

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Vol. 24, no. 2

art. no. e137, 2024

EN

High-feed axial ultrasonic vibration turning (HFUVT) is studied to explore its effects on the machining characteristics of Ti6Al4V alloy. A feed rate that is greater than the ultrasonic vibration amplitude was employed to turn this titanium alloy. The kinematics and tool flank extrusion models were established for the cutting process. Then, systematic simulation and experimental investigations were carried out to compare and analyze the cutting characteristics including the chip geometry, subsurface plastic deformation and cutting force in conventional turning (CT) and HFUVT. The results indicated that the cutting efficiency of HFUVT increased by more than 3.4 times compared with that of CT. The HFUVT produced more severely deformed Sawtooth chips, smaller shear band spacing, higher chip splitting frequency, deeper subsurface plastic deformation layer and lower cutting force. The insightful findings contribute to a comprehensive understanding of the HFUVT process and offer valuable guidance for the improving of cutting efficiency in machining difficult-to-cut materials.

2

Study on force reduction mechanism in ultrasonic assisted grinding based on single-grain scratching

He Yuhui, Zhang Jiajia, Zhou Weihua, Tang Jinyuan, Xu Yanbin, Zhang Yutong

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 2

art. no. e80, 1--14

EN

Ultrasonic vibration-assisted grinding (UAG) has been proven to be a promising grinding ability improvement technique due to the grinding force reduction. However, the reduction mechanism is still unclear due to the lack of knowledge on material softening and grain - work piece contact conditions in UAG. In this paper, we present a numerical and experimental study on ultrasonic vibration-assisted scratching (UAS) to understand the force reduction mechanism for UAG from a single-grain perspective. Based on crystal plasticity theory and dislocation density model, the constitutive model for ultrasonic-assisted deformation is established, in which the influence of vibration amplitude and strain rate is considered. To further study the acoustic softening effect, the ultrasonic assisted tensile test is conducted. The finite element model for UAS is developed with the kinematic analysis and the consideration of acoustic softening effect. The comparison between the simulated and experimental results indicates that the process force reduction under ultrasonic vibration can be attributed to (1) the reduction of contact area due to the path interference effect and (2) the yield stress reduction due to the acoustic softening effect. This research can deepen the understanding of the beneficial effect of ultrasonic vibration in UAG and offers new insight for studying other ultrasonic-assisted machining method.

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Analytical and experimental study on the surface generation mechanism in shot peening

Zhao Jiuyue, Zhou Weihua, Tang Jinyuan, Jiang Tingting, Liu Huaming

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 3

art. no. e111

EN

Shot peening is a common surface treatment technology for improving fatigue performance of component and is usually conducted after other manufacturing processes. The surface topography of shot peening directly affects the serve performance and has attracted much interest. To better understand surface generation during shot peening, an analytical model for predicting the peened surface topography was proposed by considering: (i) the random nature of the shot stream, such as the number of shots, spatial distribution, nonuniformity of shot size, and impact velocity; (ii) the overlap of dimples with initial surface and the cyclic hardening. The proposed model is verified by comparing the measured and simulated results. The model can better describe the details of the surface profile compared with the finite element method. It is found that the surface roughness Sa first increases and then decreases slowly with the increase of coverage. Besides, the peened surface of carburized and hardened gear steel shows the combined topography of grinding and shot peening. This work could provide a powerful package to efficiently predict the peened surface topography and guide industrial application in shot peening.