【摘要】：切削過(guò)程中過(guò)程阻尼的存在導(dǎo)致低速區(qū)臨界切削深度顯著增加。建立考慮過(guò)程阻尼影響的銑削穩(wěn)定性模型,對(duì)銑削過(guò)程穩(wěn)定性葉瓣圖進(jìn)行準(zhǔn)確預(yù)測(cè),對(duì)于實(shí)現(xiàn)諸如鈦合金、鎳基合金等無(wú)法采用高速加工的航空難加工材料的高效切削至關(guān)重要。本論文擬以銑削過(guò)程中產(chǎn)生的過(guò)程阻尼為研究對(duì)象,首先進(jìn)行過(guò)程阻尼建模研究并分析刀具幾何參數(shù)及加工條件等對(duì)過(guò)程阻尼的影響;其次建立了考慮過(guò)程阻尼影響的銑削穩(wěn)定性模型,采用解析法及全離散法對(duì)銑削穩(wěn)定性模型進(jìn)行了求解;最后通過(guò)顫振穩(wěn)定域試驗(yàn)驗(yàn)證了銑削穩(wěn)定性模型及其求解方法的正確性。在過(guò)程阻尼建模方面:首先描述了過(guò)程阻尼的產(chǎn)生機(jī)理,指出過(guò)程阻尼是在切削過(guò)程中刀具后刀面與已加工表面振紋之間的擠壓所產(chǎn)生的,在此基礎(chǔ)上分別通過(guò)解析法與數(shù)值法計(jì)算壓痕面積并獲得了過(guò)程阻尼的解析表達(dá)式;其次,采用能量等效法對(duì)過(guò)程阻尼系數(shù)進(jìn)行辨識(shí),通過(guò)將壓痕力所消耗的能量等效為粘性阻尼所消耗的能量,求出了壓痕力系數(shù);最后,通過(guò)數(shù)值仿真,分析了刀具幾何參數(shù)及切削條件等對(duì)過(guò)程阻尼系數(shù)的影響。在考慮過(guò)程阻尼影響的銑削穩(wěn)定性建模與解析求解方面:首先,將銑削系統(tǒng)簡(jiǎn)化為二自由度振動(dòng)系統(tǒng),基于過(guò)程阻尼力模型和再生切削力模型,建立其動(dòng)力學(xué)微分方程;其次,將動(dòng)態(tài)切削力進(jìn)行傅里葉級(jí)數(shù)展開(kāi)并只保留一次諧波,由特征方程的特征根來(lái)求解臨界軸向切削深度,進(jìn)而獲得穩(wěn)定性葉瓣圖;最后通過(guò)切削顫振試驗(yàn)驗(yàn)證模型及其解析求解方法的正確性,通過(guò)仿真來(lái)分析銑削加工工藝參數(shù)對(duì)穩(wěn)定性葉瓣圖的影響。針對(duì)經(jīng)典解析方法無(wú)法預(yù)測(cè)淺徑向浸入銑削時(shí)存在的附加穩(wěn)定性葉瓣的局限性,通過(guò)借鑒用于求解未考慮過(guò)程阻尼影響銑削穩(wěn)定性的全離散方法,實(shí)現(xiàn)了考慮過(guò)程阻尼影響的銑削穩(wěn)定性模型求解,并評(píng)估了算法的收斂性,最后通過(guò)切削顫振試驗(yàn)驗(yàn)證了求解方法的正確性。
[Abstract]:The existence of process damping in the cutting process leads to a significant increase in critical cutting depth in the low speed region. The stability model of milling considering the influence of process damping is established to predict accurately the stability of vanes in milling process. High-efficiency cutting of non-machined aeronautical materials such as nickel-based alloys is very important. In this paper, the process damping produced in milling process is taken as the research object. Firstly, the modeling of process damping is carried out and the effects of tool geometry parameters and machining conditions on the process damping are analyzed. Secondly, the stability model of milling considering the influence of process damping is established, and the stability model of milling is solved by analytic method and full discrete method. Finally, the validity of milling stability model and its solution are verified by flutter stability region test. In the modeling of process damping: firstly, the mechanism of process damping is described, and it is pointed out that the process damping is produced by extrusion between the tool surface and the machined surface in the cutting process. On this basis, the indentation area is calculated by the analytical method and the numerical method, and the analytical expression of the process damping is obtained. Secondly, the damping coefficient of the process is identified by the energy equivalent method. By equivalent the energy consumed by indentation force to the energy consumed by viscous damping, the indentation force coefficient is obtained. Finally, through numerical simulation, the effects of tool geometry parameters and cutting conditions on the damping coefficient of the process are analyzed. The modeling and analytical solution of milling stability considering the influence of process damping are as follows: firstly, the milling system is simplified as a two-degree-of-freedom vibration system, and its dynamic differential equation is established based on the process damping force model and the regenerative cutting force model. The dynamic cutting force is expanded by Fourier series and only the first harmonic is retained. The critical axial cutting depth is solved by the characteristic root of the characteristic equation, and the stable leaf lobe diagram is obtained. Finally, the correctness of the model and its analytical solution are verified by cutting flutter test, and the influence of milling process parameters on the stable vanes diagram is analyzed by simulation. In view of the limitation of the classical analytical method which can not predict the additional stable flaps in shallow radial immersion milling, the full discrete method is used to solve the problem that the process damping is not considered to affect the milling stability. The stability model of milling considering the influence of process damping is solved, and the convergence of the algorithm is evaluated. Finally, the correctness of the method is verified by cutting flutter test.
【學(xué)位授予單位】：湖南工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：TG54

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本文編號(hào)：2168542