本文關(guān)鍵詞：基于三維結(jié)構(gòu)演化表征的復(fù)合材料損傷機(jī)制研究　出處：《中國科學(xué)技術(shù)大學(xué)》2017年博士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 纖維增強(qiáng)復(fù)合材料 同步輻射CT 損傷機(jī)制 三維結(jié)構(gòu)演化

【摘要】：人工制造復(fù)合材料和自然界中生物復(fù)合材料由于具有優(yōu)異力學(xué)性能而為力學(xué)家和材料科學(xué)家所廣泛關(guān)注。復(fù)合材料這種優(yōu)異性能與其微結(jié)構(gòu)組織形態(tài)、分布、以及它們之間的相互作用密切相聯(lián)。因此,研究復(fù)合材料三維微結(jié)構(gòu)在載荷作用下的演化過程以及相互作用機(jī)理,對(duì)于深入認(rèn)識(shí)復(fù)合材料的損傷機(jī)制和力學(xué)性能分析,進(jìn)而實(shí)現(xiàn)結(jié)構(gòu)優(yōu)化設(shè)計(jì)具有重要的理論意義和工程應(yīng)用價(jià)值。本文針對(duì)具有簡(jiǎn)單結(jié)構(gòu)的單纖維復(fù)合材料、規(guī)則交錯(cuò)疊片文石纖維結(jié)構(gòu)的鳳凰螺貝殼和復(fù)雜三維隨機(jī)結(jié)構(gòu)的短纖維增強(qiáng)復(fù)合材料開展了相關(guān)研究工作。通過亞微米分辨率的同步輻射CT實(shí)驗(yàn),獲得相應(yīng)材料內(nèi)部三維形貌演化圖像(如孔洞產(chǎn)生、微裂紋萌生、擴(kuò)展等),數(shù)值化提取真實(shí)微結(jié)構(gòu)形貌和微結(jié)構(gòu)變形演化信息,得到與材料力學(xué)性能相關(guān)的力學(xué)參量,結(jié)合相應(yīng)的力學(xué)模型,分析揭示了復(fù)合材料不同三維結(jié)構(gòu)之間的相互作用機(jī)理以及孔洞、微裂紋等萌生、擴(kuò)展、演化的損傷機(jī)制。本文的主要研究?jī)?nèi)容和創(chuàng)新點(diǎn)如下:一、提出了應(yīng)變集中累積誘導(dǎo)的微裂紋萌生機(jī)制以及纖維界面變形局部化的遠(yuǎn)程損傷機(jī)制。1)開展了單纖維復(fù)合材料損傷演化的同步輻射CT實(shí)驗(yàn)研究,獲得了微裂紋萌生、擴(kuò)展和破壞過程中的三維形貌及變形演化圖像,觀察到了裂紋萌生前基體內(nèi)部局部大變形現(xiàn)象,據(jù)此提出了應(yīng)變集中累積誘導(dǎo)的微裂紋萌生機(jī)制。2)當(dāng)裂紋擴(kuò)展至纖維與基體之間的界面區(qū)域,產(chǎn)生了局部非線性變形現(xiàn)象,提出裂紋尖端影響下的纖維界面變形局部化的遠(yuǎn)程損傷機(jī)制。二、揭示了交錯(cuò)疊片文石纖維結(jié)構(gòu)微裂紋路徑偏轉(zhuǎn)的增韌機(jī)理。1)實(shí)驗(yàn)獲得了鳳凰螺貝殼中的三維微裂紋形貌演化,觀察到了反"C"型裂紋這一特殊的損傷演化現(xiàn)象,提出了第一級(jí)文石纖維結(jié)構(gòu)薄弱層多重開裂增韌機(jī)制。2)基于鳳凰螺加載實(shí)驗(yàn)中觀察到的網(wǎng)狀裂紋形貌,提出了第二級(jí)文石纖維結(jié)構(gòu)橋接裂紋面增韌機(jī)制。三、研究了短纖維復(fù)合材料的微損傷過程的關(guān)鍵機(jī)制,提出了"纖維端部聚集引發(fā)孔洞連通"的裂紋萌生模式。1)基于SR-CT實(shí)驗(yàn)觀察到纖維端部與孔洞之間的接觸關(guān)系,提出剪應(yīng)力集中導(dǎo)致孔洞萌生的機(jī)制。研究與分析表明:纖維長(zhǎng)度和取向決定了纖維端部的剪應(yīng)力集中程度,從而也導(dǎo)致是否誘發(fā)孔洞萌生。2)實(shí)驗(yàn)觀察到產(chǎn)生微裂紋的纖維端部聚集現(xiàn)象,據(jù)此提出了"纖維端部聚集引發(fā)孔洞貫通"的裂紋萌生模式。在這個(gè)模式中,相鄰纖維端部臨界距離le和纖維端部聚集數(shù)目Ne這兩個(gè)關(guān)鍵結(jié)構(gòu)參數(shù)起著決定性作用。最后,對(duì)全文的工作進(jìn)行了總結(jié),展示了本文的主要研究?jī)?nèi)容和結(jié)果,并提出了未來工作的方向和研究思路。
[Abstract]:Artificial biological composite in nature and due to their excellent mechanical properties as scientists and materials scientists concern. Distribution of the composite material of excellent properties and microstructure, morphology, and their interactions are closely linked. Therefore, research on evolution process of composite 3D micro structure under load and the interaction mechanism, to further understand the damage mechanism and the mechanical properties of the composite analysis, so as to realize the structure optimization design has important theoretical significance and practical value. Based on the single fiber composite material has the advantages of simple structure, short fiber cross laminated shell epidromis aragonite fiber structure and complex structure of three-dimensional random reinforced composite the material is studied by experiment. The sub micron resolution of synchrotron radiation CT, to obtain the corresponding material The three-dimensional morphology evolution images of internal material (such as holes generated micro crack initiation, propagation, etc.) numerical extraction of real deformation evolution of microstructure morphology and microstructure, mechanical parameters associated with the mechanical properties of the material, combined with the corresponding mechanics model, analysis between composite materials of different three-dimensional structure and interaction mechanism void, initiation and propagation of micro cracks and damage evolution mechanism. The main research contents and innovations are as follows: first, the micro crack initiation induced by strain concentration accumulation mechanism and damage mechanism of remote fiber interface deformation localization.1) carried out the research of synchrotron radiation CT single fiber composite damage evolution. The micro crack initiation, propagation and evolution of 3D image deformation and failure process, the crack was observed in the matrix of local adorable deformation phenomenon, put forward The micro crack initiation mechanism of strain concentration accumulation induced by.2) when the interface area between the crack extension to the fiber and the base deformation phenomenon of local nonlinear, remote damage mechanism of fiber interface is proposed under the influence of crack tip deformation localization. Two,.1 reveals the toughening mechanism of staggered laminated aragonite fiber structure of micro crack path deflection the evolution of 3D) Phoenix screw in the shell micro crack morphology, observed the reverse "C" crack evolution this special damage phenomenon, put forward the first level of aragonite fiber structural weak layer multiple cracking toughening mechanism of.2 mesh) Phoenix screw loading crack morphology observed in experiments based on the proposed second level structure of aragonite fibers bridging the crack surface toughening mechanism. Three, study the key mechanism of short fiber composite micro damage process, put forward the "end of the fiber aggregation caused by pore connectivity. Crack initiation mode.1) SR-CT observed the contact relationships between the fiber end and hole based on the proposed shear stress concentration mechanism leading to the initiation of the void. Research and analysis shows that the fiber length and orientation determines the shear stress concentration degree of the fiber ends, which also led to the initiation of the void is not induced by.2) experimental observation to produce the phenomenon of micro crack fiber ends together, put forward "fiber end crack void coalescence induced aggregation" initiation mode. In this mode, the adjacent fiber end critical distance le and fiber end aggregation number Ne the two key structural parameters play a decisive role. Finally, the full text of the work summarized, shows the main research contents and results, and put forward the future direction and research work.

【學(xué)位授予單位】：中國科學(xué)技術(shù)大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2017
【分類號(hào)】：TB33;TB301

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 毛靈濤;孫倩文;袁則循;劉永亮;劉紅彬;;基于CT圖像的混凝土單軸壓縮裂隙與應(yīng)變場(chǎng)分析[J];建筑材料學(xué)報(bào);2016年03期

2 毛靈濤;袁則循;連秀云;彭瑞東;劉紅彬;;基于CT數(shù)字體相關(guān)法測(cè)量紅砂巖單軸壓縮內(nèi)部三維應(yīng)變場(chǎng)[J];巖石力學(xué)與工程學(xué)報(bào);2015年01期

3 王改云;楊小娟;;改進(jìn)的分水嶺算法在圖像分割中的研究[J];電子設(shè)計(jì)工程;2014年10期

4 牛永強(qiáng);胡秋實(shí);閆德瑩;劉貴全;胡小方;許峰;繆泓;張忠;;基于數(shù)字圖像體相關(guān)的物體內(nèi)部三維位移場(chǎng)分析[J];實(shí)驗(yàn)力學(xué);2011年03期

5 汪敏;岑豫皖;胡小方;謝能剛;徐德義;;加權(quán)窗口在數(shù)字圖像相關(guān)技術(shù)中的應(yīng)用研究[J];光子學(xué)報(bào);2008年12期

6 徐偉;王希常;鄭志寬;;一種基于改進(jìn)分水嶺算法的圖像分割方法[J];計(jì)算機(jī)技術(shù)與發(fā)展;2008年12期

7 陳芬;肖揚(yáng);;多級(jí)水脊線算法在二維醫(yī)學(xué)超聲圖像中的應(yīng)用[J];計(jì)算機(jī)與數(shù)字工程;2007年05期

8 汪敏;胡小方;伍小平;;物體內(nèi)部三維位移場(chǎng)分析的數(shù)字圖像相關(guān)方法[J];物理學(xué)報(bào);2006年10期

9 黃鳳萍,李纓;碳纖維及其復(fù)合材料的發(fā)展[J];陶瓷;2005年10期

10 張立群,金日光,陳松,耿海萍,伍社毛,周彥豪;短纖維橡膠基復(fù)合材料模量的理論預(yù)測(cè)[J];材料研究學(xué)報(bào);1998年06期

，

本文編號(hào)：1396807