【摘要】：鐵路是交通運(yùn)輸體系的重要組成部分，高速鐵路作為鐵路體系的一大分支近年來(lái)正在飛速發(fā)展。列車(chē)運(yùn)行速度不斷提高，隨之而來(lái)的列車(chē)營(yíng)運(yùn)舒適性、安全可靠性、經(jīng)濟(jì)適用性問(wèn)題就愈加突出，與這些息息相關(guān)的車(chē)體輕量化就顯得尤為重要。且基于美學(xué)、動(dòng)力學(xué)的多重考量[1]，對(duì)軌道客車(chē)結(jié)構(gòu)件形狀、質(zhì)量等要求越來(lái)越高，這就對(duì)結(jié)構(gòu)件拉彎成形工藝提出了更高要求。有限元數(shù)值模擬比傳統(tǒng)經(jīng)驗(yàn)試制法更省時(shí)省力、節(jié)約成本，而位移控制模式相對(duì)于力控制變形模式有更好的成形精準(zhǔn)度，因而，通過(guò)對(duì)軌道客車(chē)鋁型材結(jié)構(gòu)件拉彎成形的研究，進(jìn)一步研究位移控制模式的三維拉彎對(duì)實(shí)際生產(chǎn)具有重要意義，也有助于加快三維拉彎設(shè)備的國(guó)產(chǎn)化進(jìn)程。本文主要對(duì)結(jié)構(gòu)件坯料及成形模具進(jìn)行三維幾何建模，再將幾何模型導(dǎo)入有限元軟件中進(jìn)行模擬計(jì)算及分析。 本文以動(dòng)車(chē)組列車(chē)車(chē)窗梁為研究對(duì)象，首先對(duì)軌道客車(chē)結(jié)構(gòu)件用6065鋁合金型材做材料性能試驗(yàn)，得到材料實(shí)際力學(xué)性能參數(shù)�；谇芯�接觸條件理論提出了三維拉彎夾頭加載軌跡計(jì)算公式，，并根據(jù)相應(yīng)公式計(jì)算得到結(jié)構(gòu)件成形加載軌跡。分析討論了數(shù)值模型建立的基本步驟，根據(jù)零件加工成形實(shí)際情況建立模型，對(duì)其進(jìn)行成形及回彈模擬。 具體的研究?jī)?nèi)容有： 1.對(duì)6065鋁合金做材料性能試驗(yàn)，得到其屈服強(qiáng)度、抗拉強(qiáng)度、彈性模量、泊松比等力學(xué)參數(shù)。 2.基于切線接觸條件理論提出三維拉彎夾頭加載軌跡計(jì)算公式，并根據(jù)公式利用數(shù)學(xué)軟件計(jì)算特定參數(shù)值，將求解得到的參數(shù)值代入公式中計(jì)算得到軌道客車(chē)結(jié)構(gòu)件的成形加載軌跡。 3.對(duì)比分析了有限元模型建立的基本步驟，包括算法與單元的選擇，接觸條件的確定，網(wǎng)格劃分等，并將計(jì)算得到的夾鉗加載軌跡作為位移邊界條件建立數(shù)值模型，進(jìn)行成形、回彈模擬計(jì)算。以最小回彈量為目標(biāo)進(jìn)行優(yōu)化，確定最佳參數(shù)，得到理想成形效果。 通過(guò)對(duì)不同總拉伸應(yīng)變量、預(yù)拉量、補(bǔ)拉量下型材零件的回彈量、截面畸變和斷裂的討論，得到如下結(jié)論：總拉伸變形量對(duì)型材成形質(zhì)量及回彈影響較大，在材料強(qiáng)度范圍內(nèi)，因零件形狀一定，不同的總拉伸變形量所對(duì)應(yīng)的坯料長(zhǎng)度不同，最大回彈量隨總拉伸應(yīng)變量增大而增大，但回彈時(shí)型材內(nèi)部應(yīng)力呈下降趨勢(shì)；預(yù)拉伸量及補(bǔ)拉伸量有利于型材成形，但對(duì)回彈量的影響不大，應(yīng)變量增大有利于卸載后的回彈穩(wěn)定性。
[Abstract]:Railway is an important part of transportation system. As a branch of railway system, high-speed railway is developing rapidly in recent years. With the increasing of train running speed, the problems of train operation comfort, safety and reliability and economic applicability become more and more prominent, which are closely related to the lightweight of the car body. Based on the multiple considerations of aesthetics and dynamics, the requirements for the shape and quality of the structural parts of the railway passenger cars are becoming higher and higher, which puts forward higher requirements for the forming process of the structural parts. The finite element numerical simulation is more time-saving and cost saving than the traditional empirical trial-production method, and the displacement control mode has better precision of forming than the force control deformation mode. It is important for practical production to further study the three-dimensional bending of displacement control mode, and it is also helpful to accelerate the process of localization of three-dimensional bending equipment. In this paper, the 3D geometric modeling of the blank and forming die of structural parts is carried out, and then the geometric model is introduced into the finite element software for simulation and analysis. In this paper, the window beam of the EMU train is taken as the research object. Firstly, the material properties of 6065 aluminum alloy profile of the rail passenger train structure are tested, and the actual mechanical properties of the material are obtained. Based on the theory of tangent contact condition, a formula for calculating the loading trajectory of a three-dimensional tension and bending chuck is proposed, and the forming loading trajectory of a structural part is obtained by the calculation of the corresponding formula. The basic steps of establishing numerical model are analyzed and discussed. According to the actual conditions of part forming, the forming and springback simulation are carried out. The specific research contents are as follows: 1. The mechanical parameters such as yield strength, tensile strength, elastic modulus and Poisson's ratio of 6065 aluminum alloy were obtained. 2. Based on the tangent contact condition theory, a formula for calculating the loading trajectory of a three-dimensional tension and bending chuck is proposed, and the specific parameter values are calculated by using mathematical software. The calculated parameters are substituted into the formula to calculate the forming loading track of the structural parts of the rail passenger car. 3. The basic steps of establishing the finite element model are compared and analyzed, including the selection of algorithm and element, the determination of contact condition, the mesh division, etc. The calculated clamp loading trajectory is taken as the displacement boundary condition and the numerical model is established for forming. Springback simulation calculation. Taking the minimum springback as the target, the optimum parameters are determined and the ideal forming effect is obtained. Through the discussion of the springback, section distortion and fracture of the profile parts under different total tensile strain, pretension and redrawing, it is concluded that the total tensile deformation has a great influence on the forming quality and springback of the profile, and in the range of material strength, the total tensile deformation has a great influence on the forming quality and springback of the profile. Because the shape of the part is constant, the length of the blank corresponding to different total tensile deformation is different, the maximum springback increases with the increase of the total tensile strain, but the internal stress of the profile decreases with the springback. The pre-drawing amount and the supplementary drawing amount are favorable to the profile forming, but have little effect on the springback amount, and the increase of the strain is beneficial to the springback stability after unloading.
【學(xué)位授予單位】：吉林大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：TG306

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本文編號(hào)：2311211