本文選題：變形測(cè)量 + 固有變形　； 參考：《重慶交通大學(xué)》2017年碩士論文

【摘要】：金屬材料的焊接過(guò)程是一個(gè)冷卻速度非常快的非線性過(guò)程。整個(gè)焊接熱循環(huán)的過(guò)程中的不均勻的溫度場(chǎng)和局部塑性變形和比容不同的組織導(dǎo)致金屬材料焊接結(jié)構(gòu)件不可避免的發(fā)生焊接變形。然而通過(guò)簡(jiǎn)單的經(jīng)驗(yàn)公式不能夠精確的預(yù)測(cè)焊接過(guò)程中發(fā)生的焊接變形,特別是大型復(fù)雜的金屬材料焊接件的焊接變形。伴隨著計(jì)算機(jī)技術(shù)的發(fā)展,基于有限元分析的方法被廣泛的應(yīng)用到計(jì)算焊接變形的領(lǐng)域。當(dāng)前基于有限元分析的焊接變形預(yù)測(cè)方法主要有兩種。一種是熱-彈-塑性有限元法,另一種方法是基于固有應(yīng)變理論的彈性有限元法。由于熱-彈-塑性有限元法運(yùn)算量大、速度慢,只適用于預(yù)測(cè)中小型焊接件的焊接變形。而固有應(yīng)變法不著眼整個(gè)焊接和冷卻過(guò)程,而是將固有變形當(dāng)作初始應(yīng)變進(jìn)行彈性有限元分析,在預(yù)測(cè)大型焊接件焊接變形方法中固有應(yīng)變法得到了更為廣泛的運(yùn)用。本文系統(tǒng)地闡述了熱彈塑性有限元理論、固有應(yīng)變有限元理論和固有變形的逆解析原理。基于高效、高精度的數(shù)值模擬研究背景,本文采用基于有限元分析的固有變形逆解析方法來(lái)獲取金屬材料焊接結(jié)構(gòu)件的固有變形。目前測(cè)量金屬材料焊接變形的方法多種多樣,本文通過(guò)分析靜態(tài)測(cè)量的各種方法和瞬態(tài)測(cè)量的各種方法,詳細(xì)闡述了這些變形測(cè)量方法的優(yōu)點(diǎn)和缺點(diǎn)。為了進(jìn)一步提高固有變形逆解析結(jié)果的精度,本文采用BRTApe×710接觸式三維坐標(biāo)測(cè)量?jī)x對(duì)金屬薄板焊接變形進(jìn)行測(cè)量,提出了獲得金屬焊接結(jié)構(gòu)件中面上三維坐標(biāo)值的計(jì)算方法。即在焊接薄板上選取的標(biāo)志點(diǎn)位置加工小孔,然后在測(cè)量這些小孔附近八個(gè)點(diǎn)的三維坐標(biāo),將測(cè)量獲得的坐標(biāo)值經(jīng)過(guò)一系列運(yùn)算得到小孔中心的三維坐標(biāo)。將計(jì)算得到的小孔中心三維坐標(biāo)值代入開發(fā)的逆解析程序可以得到金屬薄板的固有變形,最后將金屬薄板的固有變形值代入順解析程序中進(jìn)行固有變形的彈性有限元分析。為了驗(yàn)證該儀器測(cè)量結(jié)果的有效性和測(cè)量精度是否滿足高精度的要求,本論文以2 mm和3 mm金屬焊接薄板表面堆焊焊接接頭為例,以計(jì)算得到的小孔中心三維空間坐標(biāo)為已知參數(shù),基于逆解析方法求得了各成分固有變形,并采用固有應(yīng)變法預(yù)測(cè)了2 mm和3 mm金屬薄板焊接變形。通過(guò)比較分析發(fā)現(xiàn),盡管焊件板厚只相差1 mm,但焊接變形的特征和變形量卻有顯著的差別,采用該測(cè)量方法及算法能獲得焊接接頭中面上較精確的三維坐標(biāo),無(wú)論是對(duì)變形量較大的2 mm板還是對(duì)變形相對(duì)較小的3 mm板而言,基于逆解析方法都能獲得準(zhǔn)確有效的固有變形各成分。
[Abstract]:The welding process of metal material is a very fast nonlinear process. The uneven temperature field, local plastic deformation and different specific volume structure during the whole welding thermal cycle process lead to the inevitable welding deformation of the welded structural parts of metal materials. However, the simple empirical formula can not accurately predict the welding deformation in the welding process, especially the welding deformation of large and complex metal materials. With the development of computer technology, finite element analysis (FEM) is widely used to calculate welding deformation. There are two main methods of welding deformation prediction based on finite element analysis. One is thermo-elastic-plastic finite element method, the other is elastic finite element method based on inherent strain theory. Due to the large computation and slow speed, thermo-elastic-plastic finite element method is only suitable for predicting welding deformation of small and medium-sized welded parts. However, the inherent strain method does not focus on the whole welding and cooling process, but takes the inherent deformation as the initial strain for elastic finite element analysis. It is widely used in predicting the welding deformation of large welded parts. In this paper, thermoelastic-plastic finite element theory, inherent strain finite element theory and inverse analytical principle of inherent deformation are systematically expounded. Based on the research background of high efficiency and high precision numerical simulation, this paper uses the inverse analysis method of inherent deformation based on finite element analysis to obtain the inherent deformation of welded structural parts of metal materials. There are a variety of methods for measuring welding deformation of metal materials at present. The advantages and disadvantages of these methods are described in detail by analyzing various methods of static measurement and transient measurement. In order to improve the accuracy of inverse analysis of inherent deformation, this paper uses BRTApe 脳 710 contact 3D coordinate measuring instrument to measure the welding deformation of metal sheet, and puts forward a method to calculate the value of 3D coordinate on the surface of metal welded structure. In other words, the position of the mark points selected on the welded thin plate is used to process the holes, then the three-dimensional coordinates of the eight points near these holes are measured, and the coordinate values obtained from the measurements are calculated through a series of operations to get the three-dimensional coordinates of the center of the small holes. The original deformation of the thin metal plate can be obtained by replacing the calculated three-dimensional coordinate value of the center of the small hole with the developed inverse analytical program. Finally, the intrinsic deformation value of the thin metal plate can be replaced into the program to carry out the elastic finite element analysis of the inherent deformation. In order to verify the validity of the measurement results and whether the measurement accuracy meets the requirements of high accuracy, this paper takes the surfacing welding joint of 2 mm and 3 mm metal welded sheet as an example. Taking the three dimensional coordinates of the center of the small hole as known parameters, the inherent deformation of each component is obtained based on inverse analytical method, and the welding deformation of 2 mm and 3 mm metal thin plates is predicted by the inherent strain method. Through comparison and analysis, it is found that, although the thickness difference of welding plate is only 1 mm, there are significant differences in the characteristics and deformation of welding deformation. Using this measuring method and algorithm, the more accurate three-dimensional coordinates on the middle surface of welded joint can be obtained. For the 2 mm plate with large deformation and the 3 mm plate with relatively small deformation, the exact and effective components of inherent deformation can be obtained based on inverse analytical method.
【學(xué)位授予單位】：重慶交通大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TG404

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本文編號(hào)：2045119