本文關(guān)鍵詞： 機(jī)翼蒙皮 多部位損傷 發(fā)生概率 內(nèi)力再分配 剩余強(qiáng)度　出處：《哈爾濱理工大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：廣布疲勞損傷是指多個(gè)元件或者多個(gè)相似細(xì)節(jié)中存在大量的細(xì)小裂紋,這些細(xì)小裂紋在疲勞載荷的作用下發(fā)生連通,而引起結(jié)構(gòu)的剩余強(qiáng)度不能繼續(xù)承受載荷作用導(dǎo)致結(jié)構(gòu)失效。廣布疲勞損傷廣泛存在于飛機(jī)蒙皮結(jié)構(gòu)中,廣布疲勞損傷的存在降低了飛機(jī)蒙皮結(jié)構(gòu)的承載能力,嚴(yán)重影響飛機(jī)的安全和壽命,尤其是老齡飛機(jī)。廣布疲勞損傷分為多元件損傷和多部位損傷兩種形式,本文主要研究廣布疲勞損傷中的多部位損傷問(wèn)題,基于機(jī)翼蒙皮結(jié)構(gòu)和機(jī)翼蒙皮常用的2024鋁合金材料,根據(jù)多部位損傷發(fā)生和發(fā)展過(guò)程研究多部位損傷發(fā)生的概率、多部位損傷內(nèi)力再分配問(wèn)題和多部位損傷的剩余強(qiáng)度。本文的研究對(duì)深入了解多部位損傷的形成及發(fā)展過(guò)程具有重要的參考價(jià)值,也為飛機(jī)結(jié)構(gòu)的安全設(shè)計(jì)和壽命評(píng)估提供有力的參考依據(jù),對(duì)我國(guó)的航空以及國(guó)防建設(shè)事業(yè)也具有重大的現(xiàn)實(shí)意義。在研究多部位損傷發(fā)生概率方面,首先給出多部位損傷發(fā)生的判定依據(jù),然后在假設(shè)各個(gè)細(xì)節(jié)具有相同疲勞特征和產(chǎn)生裂紋隨機(jī)獨(dú)立性的條件下,根據(jù)概率斷裂力學(xué)當(dāng)量初始裂紋分布的理論和數(shù)理統(tǒng)計(jì)中的三參數(shù)威布爾分布建立了預(yù)測(cè)多細(xì)節(jié)結(jié)構(gòu)發(fā)生多部位損傷概率的數(shù)學(xué)模型,具體建立了載荷循環(huán)次數(shù)和發(fā)生概率之間的函數(shù)關(guān)系。最后,通過(guò)2024鋁合金薄板單細(xì)節(jié)和三細(xì)節(jié)的疲勞試驗(yàn)對(duì)模型的合理性進(jìn)行驗(yàn)證。經(jīng)驗(yàn)證,模型可以很好地預(yù)測(cè)多細(xì)節(jié)結(jié)構(gòu)在一定載荷循環(huán)次數(shù)下發(fā)生多部位損傷的概率,但預(yù)測(cè)結(jié)果偏于保守。在研究多部位損傷內(nèi)力再分配方面,首先對(duì)復(fù)雜的多部位損傷問(wèn)題進(jìn)行簡(jiǎn)化處理,根據(jù)某民機(jī)機(jī)翼蒙皮結(jié)構(gòu)得到多部位損傷結(jié)構(gòu)的兩個(gè)基本簡(jiǎn)化模式,再運(yùn)用Abaqus和Franc3d建立裂紋有限元模型研究?jī)蓚�(gè)基本多部位損傷結(jié)構(gòu)的應(yīng)力強(qiáng)度因子中結(jié)構(gòu)綜合修正因子,在得到結(jié)構(gòu)綜合修正因子中的組合修正因子和局部載荷再分配因子與主裂紋長(zhǎng)度存在函數(shù)關(guān)系的結(jié)論后,通過(guò)這種函數(shù)關(guān)系研究了組合修正因子和局部載荷再分配因子與主裂紋長(zhǎng)度的變化規(guī)律,間接研究了多部位損傷內(nèi)力再分配的變化規(guī)律。得出一定載荷情況下,多部位損傷結(jié)構(gòu)的內(nèi)部載荷是不斷進(jìn)行分配的,分配的規(guī)律與結(jié)構(gòu)形式和裂紋分布等因素有關(guān)等的結(jié)論。在多部位損傷剩余強(qiáng)度研究方面,首先根據(jù)前文對(duì)多部位損傷內(nèi)力再分配問(wèn)題研究的結(jié)論和試驗(yàn)標(biāo)準(zhǔn)設(shè)計(jì)了兩類同細(xì)節(jié)不同裂紋分布的含有多部位損傷結(jié)構(gòu)的試驗(yàn)件,試驗(yàn)件材料采用2024鋁合金材料。通過(guò)兩類多部位損傷結(jié)構(gòu)試驗(yàn)件的剩余強(qiáng)度試驗(yàn),討論了凈截面屈服計(jì)算方法、基于Swift連通準(zhǔn)則的計(jì)算方法和線彈性條件下斷裂力學(xué)的計(jì)算方法這三種常用的剩余強(qiáng)度計(jì)算方法在多部位損傷結(jié)構(gòu)剩余強(qiáng)度計(jì)算方面的適用性。最后得出結(jié)論:同細(xì)節(jié)不同裂紋分布對(duì)多部位損傷結(jié)構(gòu)剩余強(qiáng)度有影響,凈截面屈服計(jì)算方法較其他兩種計(jì)算方法更準(zhǔn)確。
[Abstract]:Widespread fatigue damage refers to the existence of a large number of small cracks more elements or more similar details, these small cracks in fatigue load under the effect of connectivity, caused by the residual strength of the structure can not continue to bear the load may cause structure failure. Widespread fatigue damage is widely existed in the aircraft structure, widespread fatigue the existence of damage reduces the bearing capacity of aircraft structure, seriously affect the safety and life of aircraft, especially aging aircraft. Widespread fatigue damage is divided into multiple components damage and multiple site damage in two forms, this paper mainly studies the widely distributed multi site damage fatigue damage, skin structure and wing wing skin commonly used 2024 Aluminum Alloy based material according to the occurrence and development process of multi site damage probability of multiple site damage, multiple site damage redistribution problem and multiple site damage The residual strength. This study has important reference value for understanding the formation and development process of multiple site damage, but also provide reference for the safety design and life assessment of aircraft structure, also has great practical significance for China's aviation and national defense construction. The probability of occurrence in the study of multiple site damage firstly, multiple site damage criterion of the conditions and have the same characteristics in detail and fatigue crack random assumption of independence, according to the three parameter Weibull distribution model was established to predict the detail structure of the probability of occurrence of multiple site damage probability fracture mechanics equivalent initial crack distribution theory and mathematical statistics. How to establish the function relationship between the load cycles and occurrence probability. Finally, by 2024 Aluminum Alloy details and the details of the three single sheet The fatigue test of the rationality of the model is verified. Verification results show that the model can well predict the probability of multiple details structure occurs in certain load cycles under multiple site damage, but the prediction result is conservative. The internal force redistribution in study of multiple site damage, the multiple site damage complex problem is simplified, according to the basic a simplified model of a civil aircraft wing skin structure structure with multiple site damage two, then use Abaqus and Franc3d to establish the finite element model of crack two basic structure with multiple site damage stress intensity factors in the structure of comprehensive correction factor is a function of a combination of correction factor and local load redistribution factor and the main crack length in structure the comprehensive correction factor in the conclusion, through this function relationship of combined correction factor and local load redistribution factor and main crack Changes of the length of the variation of the indirect multiple site damage redistribution. The load conditions, the structure of multi site damage is ongoing internal load distribution, distribution regularity and conclusion structure and distribution of cracks and other factors. The residual strength of the multiple site damage, according to the study the redistribution of internal force on the above conclusions and multiple site damage testing standard test piece is designed with the structure of multi site damage two similar details different crack distribution, the test materials using 2024 Aluminum Alloy material. By two kinds of multiple site damage residual strength test structure of the test piece, the net section yield calculation method, method damage in many parts of the calculation method and the linear elastic fracture mechanics criterion Swift connected under these three kinds of commonly used based on the residual strength Finally, it is concluded that different crack distributions with the same details affect the residual strength of multi site damaged structures. The net section yield calculation method is more accurate than the other two methods.

【學(xué)位授予單位】：哈爾濱理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：V215

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