【摘要】：小汽車車身主要是板料覆蓋件,且由沖壓模具沖壓而成,其質(zhì)量的好壞會影響到汽車整車的質(zhì)量。板料沖壓成形過程中除了需要考慮板材的力學(xué)性能之外,還需要有合理的成形工藝參數(shù)。本文針對某小車前門外板沖壓成形過程中可能出現(xiàn)缺陷的主要原因,采用數(shù)值模擬方法對影響成形質(zhì)量的沖壓工藝參數(shù)進(jìn)行分析和優(yōu)化,從而來避免這些缺陷的產(chǎn)生,達(dá)到提高產(chǎn)品質(zhì)量,降低成本的目的。本文以板料在沖壓成形的力學(xué)理論和有限元數(shù)值模擬理論為基礎(chǔ),采用非線性有限元軟件Dynaform對某型號小車前門外板的沖壓工藝參數(shù)進(jìn)行了數(shù)值模擬分析和研究。本文主要研究內(nèi)容如下:(1)運(yùn)用板料成形的數(shù)值模擬方法,對小車前門外板的結(jié)構(gòu)工藝特點(diǎn)進(jìn)行了分析,并建立起小車前門外板的有限元模型。(2)運(yùn)用Dynaform對小車前門外板的有限元模型進(jìn)行了沖壓成形的數(shù)值模擬,獲得了成形后的應(yīng)力圖、應(yīng)變圖、厚度變化圖以及成形極限圖,從圖中根據(jù)成形極限指標(biāo)評估了工件的沖壓狀況,還預(yù)測了產(chǎn)品某些部位可能出現(xiàn)的缺陷:起皺、拉裂等,并分析了產(chǎn)生這些缺陷的主要原因。(3)通過研究壓邊力、摩擦系數(shù)、板料厚度和沖壓速度等工藝參數(shù)對產(chǎn)品沖壓成形過程的影響規(guī)律,運(yùn)用Dynaform軟件數(shù)值模擬的結(jié)果,分別確定了這四個沖壓工藝參數(shù)的合理取值范圍。(4)運(yùn)用正交試驗(yàn)方法對小車前門外板沖壓工藝參數(shù)進(jìn)行試驗(yàn)設(shè)計。從試驗(yàn)結(jié)果中提取最大減薄率和最大增厚率兩個指標(biāo),獲得板料成形沖壓工藝參數(shù)的較優(yōu)組合,并將優(yōu)化后的沖壓工藝參數(shù)進(jìn)行數(shù)值模擬,模擬的結(jié)果證明了優(yōu)化結(jié)果的合理性和優(yōu)化方法的可靠性。
文內(nèi)圖片：
圖片說明：圖２．１應(yīng)力－應(yīng)變圖逡逑Ｆｉ．２．１邋ｓｔｒｅｓｓ－ｓｔｒａｉｎ邋ｄｉａｒａｍ逡逑
[Abstract]:The car body is mainly sheet metal panel, and is made of stamping die. The quality of the car body will affect the quality of the whole car. In the process of sheet metal stamping, not only the mechanical properties of sheet metal need to be considered, but also reasonable forming process parameters are needed. In view of the main causes of defects in the stamping process of the outer plate of the front door of a car, this paper analyzes and optimizes the stamping process parameters that affect the forming quality by using the numerical simulation method, so as to avoid the occurrence of these defects and achieve the purpose of improving the product quality and reducing the cost. Based on the mechanical theory and finite element numerical simulation theory of sheet metal forming, the stamping process parameters of the front door outer plate of a certain type of trolley are analyzed and studied by using the nonlinear finite element software Dynaform in this paper. The main contents of this paper are as follows: (1) the structural and technological characteristics of the outer plate of the front door of the car are analyzed by using the numerical simulation method of sheet metal forming, and the finite element model of the outer plate of the front door of the car is established. (2) the finite element model of the outer plate of the front door of the car is used to simulate the stamping forming of the outer plate of the front door of the car, and the stress diagram, strain diagram, thickness change diagram and forming limit diagram after forming are obtained. According to the forming limit index, the stamping condition of the workpiece is evaluated, and the possible defects in some parts of the product, such as wrinkling and cracking, are predicted, and the main causes of these defects are analyzed. (3) by studying the influence of blank holder force, friction coefficient, sheet metal thickness and stamping speed on the stamping process of the product, the results of numerical simulation with Dynaform software are carried out. The reasonable range of the four stamping process parameters is determined respectively. (4) the orthogonal test method is used to design the stamping process parameters of the front door outer plate of the trolley. The maximum thinning rate and the maximum thickening rate are extracted from the experimental results, and the optimal combination of the stamping process parameters of sheet metal forming is obtained. The optimized stamping process parameters are simulated by numerical simulation. The simulation results prove the rationality of the optimization results and the reliability of the optimization method.
【學(xué)位授予單位】：中南林業(yè)科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：U466;TG386

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