本文選題：功能梯度材料　切入點(diǎn)：圓柱殼　出處：《華南理工大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：功能梯度材料(functionally graded materials,FGM)是一種兩相材料共同混合的新型復(fù)合材料。此材料一般由陶瓷和金屬復(fù)合組成,在宏觀尺度上各組分材料的體積含量沿材料厚度方向連續(xù)變化,因此宏觀物性也呈現(xiàn)連續(xù)變化的特征;這在很大程度上避免或降低了傳統(tǒng)疊層復(fù)合材料因物性不連續(xù)在界面產(chǎn)生的應(yīng)力集中現(xiàn)象,因此功能梯度材料的力學(xué)性能具有力學(xué)特性上的優(yōu)越性,有非常高的應(yīng)用潛力。由于功能梯度材料的金屬相材料在屈曲過程中往往會表現(xiàn)出一些韌性,因此,采用彈塑性的本構(gòu)模型描述功能梯度材料,有著重要的意義。本文首先對功能梯度材料當(dāng)前常用的研究模型進(jìn)行了對比分析,指出了現(xiàn)有研究的一些不足之處,再將彈塑性本構(gòu)理論,層疊復(fù)合板理論相結(jié)合,針對功能梯度材料的彈塑性本構(gòu)模型提出了一個(gè)完整的架構(gòu)并在ABAQUS軟件中進(jìn)行了UMAT定義。在UMAT模塊中定義了材料的多個(gè)屬性并得出了彈塑性雅克比矩陣,并驗(yàn)證了該做法的實(shí)用性。本文采用了上述的分析方法為基礎(chǔ),建立了有限元分析模型,通過計(jì)算結(jié)果的模態(tài)等進(jìn)行了分析,驗(yàn)證了分析模型的可用性。本文還通過上述的有限元分析模型,引入關(guān)于模態(tài)的初始缺陷,對含缺陷的功能梯度材料圓柱殼進(jìn)行了數(shù)值計(jì)算,探討了缺陷、徑厚比、梯度參數(shù),計(jì)算單元等因素對計(jì)算結(jié)果的影響,闡述了缺陷與極限屈曲載荷之間的聯(lián)系,揭示了各因素和屈曲荷載間的相關(guān)關(guān)系。在本文的內(nèi)容的最后,利用了ABAQUS軟件中的顯式動力有限元方法,建立了功能梯度材料圓柱殼的動態(tài)屈曲模型,對模型進(jìn)行了計(jì)算分析,并對模型的網(wǎng)格密度等因素影響進(jìn)行了比較。研究結(jié)果表明,上述的各項(xiàng)參數(shù)對功能梯度材料圓柱殼的動態(tài)屈曲有重要的影響。
[Abstract]:Functionally graded material materials (FGM) is a new type of composite material, which is composed of ceramic and metal composites, and the volume content of each component varies continuously with the thickness of the material at macroscopic scale. Therefore, the macroscopic physical properties also show the characteristics of continuous variation, which to a great extent avoids or reduces the stress concentration in the interface of traditional laminated composites due to the discontinuity of physical properties. Therefore, the mechanical properties of functionally graded materials have the advantages of mechanical properties and have a high potential for application. As the metal phase materials of functionally graded materials often exhibit some toughness during buckling, It is of great significance to describe functionally graded materials with elastoplastic constitutive models. In this paper, the current research models of functionally graded materials are compared and analyzed, and some shortcomings of the existing researches are pointed out. Then the elastic-plastic constitutive theory and the laminated composite plate theory are combined. This paper presents a complete framework for the elastoplastic constitutive model of functionally graded materials and defines the UMAT in ABAQUS software. In the UMAT module, several properties of the material are defined and the elastic-plastic Jacobian matrix is obtained. The practicability of the method is verified. Based on the above analysis method, the finite element analysis model is established, and the modal of the calculated results is analyzed. Through the above finite element analysis model, the initial defects of the modal are introduced, and the defect, diameter to thickness ratio, gradient parameters of functionally graded material cylindrical shells with defects are numerically calculated. The influence of calculation elements on the calculation results is discussed. The relationship between defects and ultimate buckling loads is expounded, and the correlation between each factor and buckling load is revealed. At the end of this paper, Using explicit dynamic finite element method in ABAQUS software, the dynamic buckling model of functionally graded cylindrical shells is established. The model is calculated and analyzed, and the effects of factors such as mesh density on the model are compared. The above parameters have an important effect on the dynamic buckling of functionally graded cylindrical shells.
【學(xué)位授予單位】：華南理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TB34

【參考文獻(xiàn)】

相關(guān)碩士學(xué)位論文 前1條

1 陶憲斌;功能梯度材料彈塑性損傷耦合分析[D];哈爾濱工業(yè)大學(xué);2011年

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本文編號：1603450