Ma Jingmin, Xu Jianfeng, Li Longfei, Liu Xingguang, Gao Ming
College of Energy and Mining Engineering, Shandong University of Science and Technology, Qingdao 266590, China.
Mechanical and Electronic Engineering College, Shandong Provincial Key Laboratory of Horticultural Machineries and Equipments, Shandong Agricultural Equipment Intelligent Engineering Laboratory, Shandong Agricultural University, Tai'an 271018, China.
Materials (Basel). 2022 Aug 8;15(15):5465. doi: 10.3390/ma15155465.
Chattering in composite deep-hole boring can directly affect surface processing quality and efficiency and has always been a research hotspot in machining mechanics. In this study, based on Euler-Bernoulli beam theory, the fine control equations for the cutting stability of composite variable-section boring bars were established using the Hamilton principle, in which the sectional change and internal damping of the material were considered. Next, using the Galerkin method and semi-discrete method, the effects of the taper ratio, damping ratio, length-to-diameter ratio, and ply angle on the free vibration characteristics and cutting stability were analyzed in detail. The results show that at a low damping ratio, both the first-order inherent frequency and boring stability can be enhanced with the increase in the taper ratio; at a large damping ratio, increasing the taper ratio can reduce the first-order inherent frequency and boring stability. Finally, the effects of the sectional change on the inherent frequency, displacement response, and convergence were analyzed. A numerical simulation was performed for the model reliability validation. The present research results can provide a theoretical basis and technical guidance for analyzing the cutting stability and fine control of composite variable-section boring bars with large length-to-diameter ratios.
复合材料深孔镗削中的颤振会直接影响表面加工质量和效率，一直是加工力学领域的研究热点。本研究基于欧拉 - 伯努利梁理论，利用哈密顿原理建立了考虑材料截面变化和内部阻尼的复合材料变截面镗杆切削稳定性精细控制方程。接着，采用伽辽金法和半离散法，详细分析了锥度比、阻尼比、长径比和铺层角度对自由振动特性和切削稳定性的影响。结果表明，在低阻尼比下，一阶固有频率和镗削稳定性都可随锥度比的增加而提高；在大阻尼比下，增大锥度比会降低一阶固有频率和镗削稳定性。最后，分析了截面变化对固有频率、位移响应和收敛性的影响。进行了数值模拟以验证模型可靠性。本研究结果可为分析大长径比复合材料变截面镗杆的切削稳定性及精细控制提供理论依据和技术指导。
