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Siyu Liang,Guangjun Liu,Gaoyang Wu,Tao Chen 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.2
In the process of Al-added pearlitic gray cast iron material cutting, the tool surface will form an adhesive layer due to extrusion and friction, which will have a complex impact on the machining quality and tool life. Therefore, it is necessary to study its formation process and tool wear mechanism in detail. This paper investigates the evolution laws of tool wear and workpiece surface roughness in different cutting parameters, which is based on orthogonal tests. Using the data of the orthogonal tests, an optimization model is carried out to find optimum cutting parameters which can keep a good balance among cutting efficiency, machined surface roughness and tool life. Then, the SEM and energy spectrometer are used to analyze the formation of adhesive layers and the distribution of elements. Compared with the comprehensive test, the orthogonal test can reduce the number of experiments and improve the efficiency on the premise of ensuring accuracy and can be easily applied to practical production. And the results of SEM micrograph and elements distribution map show that the stability of the mass ratio of aluminium to titanium on the tool surface can directly reflect the stability of the adhesive layer, thus affecting the tool life and the machined surface quality.
Cao Miaomiao,Shao Zhiyu,Wu Siyu,Dong Chaochao,Yang Xiaotian 대한조선학회 2021 International Journal of Naval Architecture and Oc Vol.13 No.1
The water entry behaviors of projectiles with different cone-headed angles were studied numerically, experimentally and theoretically, mainly focusing on the hydrodynamic impact in the initial stage. Based on MMALE algorithm, it was proposed a formula of impact deceleration, which relied on the initial entry velocity and cone-headed angle. Meanwhile, in order to verify the validity of the simulation model, experiments using accelerometer and high-speed camera were carried out, and their results were in a good agreement with simulation results. Also, theoretical calculation results of cavity diameter were compared with experiments and simulation results. It was observed that the simulation method had a good reliability, which would make forecast on impact deceleration in an engineering project.
Zhen Wang,Qiyang Tan,Pengfei Shi,Ge Yang,Siyu Zhu,Guoshan Xu,Bin Wu,Jianyun Sun 국제구조공학회 2020 Smart Structures and Systems, An International Jou Vol.26 No.3
Hybrid simulation (HS) is a versatile tool for structural performance evaluation under dynamic loads. Although real structural responses are often multiple-directional owing to an eccentric mass/stiffness of the structure and/or excitations not along structural major axes, few HS in this field takes into account structural responses in multiple directions. Multi-directional loading is more challenging than uni-directional loading as there is a nonlinear transformation between actuator and specimen coordinate systems, increasing the difficulty of suppressing loading error. Moreover, redundant actuators may exist in multi-directional hybrid simulations of large-scale structures, which requires the loading strategy to contain ineffective loading of multiple actuators. To address these issues, lately a new strategy was conceived for accurate reproduction of desired displacements in bi-directional hybrid simulations (BHS), which is characterized in two features, i.e., iterative displacement command updating based on the Jacobian matrix considering nonlinear geometric relationships, and force-based control for compensating ineffective forces of redundant actuators. This paper performs performance validation and application of this new mixed loading strategy. In particular, virtual BHS considering linear and nonlinear specimen models, and the diversity of actuator properties were carried out. A validation test was implemented with a steel frame specimen. A real application of this strategy to BHS on a full-scale 2-story frame specimen was performed. Studies showed that this strategy exhibited excellent tracking performance for the measured displacements of the control point and remarkable compensation for ineffective forces of the redundant actuator. This strategy was demonstrated to be capable of accurately and effectively reproducing the desired displacements in large-scale BHS.