本文選題：定模動(dòng)輥　切入點(diǎn)：激光輔助加熱　出處：《北方工業(yè)大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：變截面輥彎成型是一種新興的材料塑型加工工藝,這種工藝能夠解決材料截面復(fù)雜多變,板料兩側(cè)高度不對(duì)稱等傳統(tǒng)輥彎成型難以實(shí)現(xiàn)的加工問題。在一些特殊場(chǎng)合需要用到截面較窄或者截面形狀非常復(fù)雜的承載零部件,普通的變截面輥彎成型無(wú)法完成一次成型,本文提出一種能夠一次加工成型的加工工藝,采用該種工藝能成型強(qiáng)度較高,成型半徑較小的彎曲件：定模動(dòng)輥?zhàn)兘孛孑亸澇尚�。由于高�?qiáng)鋼板強(qiáng)度高、塑性差、材料的延伸率較低,導(dǎo)致加工成型困難,容易在折彎處產(chǎn)生裂紋或材料回彈較大等問題。本文采用激光輔助加熱成型的方案來(lái)解決上述問題。 本文基于熱-應(yīng)力完全耦合的分析方法,在大型有限元分析軟件ABAQUS中,構(gòu)建了激光輔助的定模動(dòng)輥輥彎成型裝備成型過(guò)程。以DP980高強(qiáng)度鋼板為研究對(duì)象,仿真模擬了成型過(guò)程中板料的溫度場(chǎng)、應(yīng)力場(chǎng)的分布,分析了板料塑性應(yīng)變區(qū)域及軋輥成型力的變化,并對(duì)比成型角度的關(guān)系對(duì)成型過(guò)程中的材料回彈進(jìn)行了預(yù)測(cè)。主要研究工作如下： (1)溫度場(chǎng)方面：介紹了熱成型研究歷程及發(fā)展現(xiàn)狀,分析了熱成型方法,實(shí)現(xiàn)了熱導(dǎo)率、比熱容等熱學(xué)關(guān)鍵參數(shù)的導(dǎo)入,運(yùn)用傳熱學(xué)及殼體溫度場(chǎng)分布設(shè)置了板料及上下模具相互耦合的邊界條件。通過(guò)對(duì)比不同溫度場(chǎng)仿真過(guò)程得出最適宜加工溫度。 (2)應(yīng)力場(chǎng)方面：導(dǎo)入了仿真模擬的力學(xué)關(guān)鍵參數(shù),如屈服應(yīng)力、彈性模量、塑性應(yīng)變等。分析了等效應(yīng)力及等效塑性應(yīng)變,并得到各道次軋輥成型力變化曲線,掌握了成型過(guò)程中彈塑性變化的規(guī)律。 (3)成型速度及回彈預(yù)測(cè)方面：分析成型后板料的成形角,預(yù)測(cè)加工過(guò)程中可能產(chǎn)生的回彈,以及比較仿真速度及模擬結(jié)果,得到成型效果與加工速度的關(guān)系。 通過(guò)完全的熱力耦合有限元方法仿真模擬了激光輔助的定模動(dòng)輥輥彎成型生產(chǎn)過(guò)程,與試驗(yàn)結(jié)果進(jìn)行比對(duì),發(fā)現(xiàn)仿真分析結(jié)果正確,對(duì)回彈和產(chǎn)生的缺陷進(jìn)行了預(yù)測(cè),并得到了適合加工的溫度為600℃,適合加工的速度為50mm/s,適合加工的加熱方式為均勻激光加熱,加熱的最佳位置為板料成型區(qū)域。該結(jié)果的提出對(duì)于激光輔助加熱的定模動(dòng)輥輥彎成型的熱力耦合分析過(guò)程提供了理論基礎(chǔ),并對(duì)該設(shè)備的改進(jìn)以及生產(chǎn)實(shí)踐具有很重要的意義。
[Abstract]:Variable cross section roll bending forming is a new material plastic processing technology, which can solve the complex and changeable material cross section. In some special cases, the bearing parts with narrow section or very complicated section shape are needed. The common variable cross section roll bending can not complete one forming, and it is difficult to realize the processing problem of the traditional roll bending forming, such as the height asymmetry on both sides of the sheet metal. In this paper, a kind of processing technology that can be processed at one time is put forward. The bending part with higher strength and smaller forming radius can be formed by using this process. Because of the high strength of high strength steel plate, the plasticity is poor because of the variable cross section roll bending forming of fixed die moving roll. The low elongation of the material leads to the difficulty of processing and forming, and it is easy to produce cracks at the bending place or the material rebound is large, etc. In this paper, the laser-assisted heating molding scheme is used to solve the above problems. Based on the thermal-stress coupling analysis method, the laser assisted forming process of moving roll bending equipment is constructed in the large-scale finite element analysis software ABAQUS. The DP980 high strength steel plate is taken as the research object. The distribution of the temperature field and stress field of the sheet metal during the forming process is simulated, and the variation of the plastic strain region of the sheet metal and the forming force of the roll is analyzed. The springback of the material during the molding process is predicted by comparing the relationship of the angle of molding. The main research work is as follows:. 1) in the aspect of temperature field, this paper introduces the research history and development status of thermoforming, analyzes the method of thermoforming, and realizes the introduction of key thermal parameters, such as thermal conductivity, specific heat capacity, etc. By using heat transfer theory and the temperature field distribution of the shell, the boundary conditions of the coupling between the sheet metal and the upper and lower die are set up, and the optimum processing temperature is obtained by comparing the simulation process of different temperature fields. 2) stress field: the key mechanical parameters such as yield stress, elastic modulus and plastic strain are introduced. The equivalent stress and plastic strain are analyzed, and the forming force curves of each pass roll are obtained. The rule of elastoplastic change in forming process is grasped. 3) forming speed and springback prediction: analyzing the forming angle of the formed sheet metal, predicting the springback that may occur in the process of processing, and comparing the simulation speed and the simulation result, the relationship between the forming effect and the processing speed is obtained. The production process of laser assisted rolling roll bending is simulated by a complete thermo-mechanical coupled finite element method. The results are compared with the experimental results. The simulation results are correct, and the springback and defects are predicted. The suitable processing temperature is 600 鈩，

本文編號(hào)：1636332