本文選題：機(jī)床主軸 + 刀尖點(diǎn)頻響函數(shù)��； 參考：《大連理工大學(xué)》2016年碩士論文

【摘要】：發(fā)生在銑刀與工件接觸面之間的再生顫振會(huì)導(dǎo)致銑削加工過程出現(xiàn)不穩(wěn)定現(xiàn)象,降低工件表面質(zhì)量和材料去除率,降低生產(chǎn)效率,甚至損壞刀具和機(jī)床主軸系統(tǒng)。抑制再生顫振已經(jīng)成為機(jī)床穩(wěn)定性主要研究方向。用來預(yù)測(cè)銑削加工穩(wěn)定域的穩(wěn)定性葉瓣圖為抑制顫振的產(chǎn)生起到了指導(dǎo)作用。構(gòu)建已知刀具組合方式的穩(wěn)定性葉瓣圖則需要刀尖點(diǎn)頻響函數(shù)。因此,本文針對(duì)刀尖點(diǎn)頻響函數(shù)預(yù)測(cè)過程中所涉及的動(dòng)力學(xué)模型,耦合理論與預(yù)測(cè)方法等方面進(jìn)行了研究。建立了銑削系統(tǒng)的動(dòng)力學(xué)模型,并進(jìn)行了模態(tài)實(shí)驗(yàn)。根據(jù)刀具與工件的剛性,將動(dòng)力學(xué)模型分別劃分為柔性刀具剛性工件與柔性刀具柔性工件銑削動(dòng)力學(xué)模型；給出了基于錘擊實(shí)驗(yàn)的模態(tài)分析法,獲取了后續(xù)需要進(jìn)行刀尖點(diǎn)頻響函數(shù)預(yù)測(cè)的實(shí)驗(yàn)刀具前四階固有頻率。在分析響應(yīng)耦合方法獲取的機(jī)床主軸系統(tǒng)結(jié)構(gòu)響應(yīng)時(shí),考慮了剪切力和轉(zhuǎn)動(dòng)慣量對(duì)計(jì)算結(jié)構(gòu)響應(yīng)的影響。主軸中的結(jié)構(gòu)受力后變形復(fù)雜,響應(yīng)耦合方法能全面地反映出結(jié)構(gòu)的彎曲和扭轉(zhuǎn)響應(yīng)；與此同時(shí),相比于采用Euler-Bernoulli模型獲取的結(jié)構(gòu)響應(yīng),考慮到剪切力和轉(zhuǎn)動(dòng)慣量的Timoshenko模型能夠更準(zhǔn)確地反應(yīng)梁在受力情況下的彎曲與剪切變形。尤其是在主軸中長(zhǎng)徑比較低的梁部件和部件經(jīng)裝配后長(zhǎng)徑比降低的情況。提出一種將數(shù)值計(jì)算與敲擊實(shí)驗(yàn)結(jié)合的刀尖點(diǎn)頻響函數(shù)預(yù)測(cè)方法。通過對(duì)刀柄和測(cè)試刀具敲擊實(shí)驗(yàn),結(jié)合對(duì)測(cè)試刀具響應(yīng)的數(shù)值計(jì)算結(jié)果,實(shí)現(xiàn)對(duì)刀具和刀柄結(jié)合面的參數(shù)識(shí)別。隨后利用參數(shù)辨識(shí)的結(jié)果,綜合對(duì)預(yù)測(cè)刀具響應(yīng)的數(shù)值計(jì)算,從而實(shí)現(xiàn)對(duì)刀尖點(diǎn)頻響函數(shù)的預(yù)測(cè)。此預(yù)測(cè)方法可以在保證精度的同時(shí),減少重復(fù)敲擊實(shí)驗(yàn),實(shí)現(xiàn)刀尖點(diǎn)頻晌函數(shù)的快速預(yù)測(cè)。最后,對(duì)刀尖點(diǎn)頻響函數(shù)預(yù)測(cè)方法進(jìn)行實(shí)驗(yàn)驗(yàn)證。預(yù)測(cè)的結(jié)果與直接通過敲擊實(shí)驗(yàn)獲得的頻響函數(shù)具有很好的一致性,并且在頻率和幅值上都較基于Euler-Bernoulli模型的預(yù)測(cè)結(jié)果更為精確,幅值上的精度提高尤為顯著。通過實(shí)驗(yàn)驗(yàn)證了預(yù)測(cè)方法的有效性與精確性。
[Abstract]:The regenerative chatter between the milling cutter and the workpiece interface will lead to the instability of the milling process, reduce the surface quality of the workpiece and the material removal rate, reduce the production efficiency, and even damage the tool and the spindle system of the machine tool. Restraining regenerative flutter has become the main research direction of machine tool stability. The stable flaps used to predict the stable region of milling play a guiding role in suppressing flutter. The frequency response function of the tip point is required to construct the stable leaf flap plan of the known tool combination. Therefore, the dynamic model, coupling theory and prediction method involved in the prediction of the frequency response function of the knife tip are studied in this paper. The dynamic model of milling system is established and the modal experiment is carried out. According to the rigidity of tool and workpiece, the dynamic model is divided into two dynamic models: flexible tool rigid workpiece and flexible cutting tool flexible workpiece milling dynamics model, and the modal analysis method based on hammering experiment is given. The first four natural frequencies of the experimental tool which need to predict the frequency response function of the tool tip are obtained. The influence of shear force and moment of inertia on the structural response of the machine tool spindle system is considered in the analysis of the structural response obtained by the coupling response method. The deformation of the structure in the main shaft is complex, and the response coupling method can fully reflect the bending and torsional response of the structure, and at the same time, compared with the structural response obtained by the Euler-Bernoulli model, the coupling method can fully reflect the bending and torsional response of the structure. The Timoshenko model, which takes into account the shear force and the moment of inertia, can reflect the bending and shear deformation of the beam more accurately. In particular, the ratio of length to diameter of beam parts and components with low length and diameter is reduced after assembly. A method for predicting the frequency response function of knife tip is presented, which combines numerical calculation with percussion experiment. Based on the impact experiments of the tool handle and the test tool, and the numerical results of the response of the testing tool, the parameter identification of the tool and the joint surface of the tool holder is realized. Based on the result of parameter identification, the numerical calculation of predicting tool response is synthesized, and the frequency response function of tool tip is predicted. This prediction method can not only guarantee the accuracy but also reduce the repeated tapping experiments and realize the fast prediction of the frequency function of the knife tip. Finally, the prediction method of frequency response function of knife tip is verified by experiment. The predicted results are in good agreement with the frequency response function obtained from the percussion experiment, and are more accurate in frequency and amplitude than those based on Euler-Bernoulli model, especially in amplitude. The validity and accuracy of the prediction method are verified by experiments.
【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類號(hào)】：TG659

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本文編號(hào)：1902817