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1、一維六方準(zhǔn)晶中界面裂紋與位錯(cuò)的交互作用
摘 要:應(yīng)用復(fù)變函數(shù)的方法,研究了一維六方準(zhǔn)晶雙材料中單個(gè)圓弧形夾雜界面裂紋與基體中螺型位錯(cuò)之間的交互作用問題,求得了該問題的封閉形式解.當(dāng)界面裂紋消失時(shí),所得的退化結(jié)果與已有文獻(xiàn)一致.導(dǎo)出了位錯(cuò)在圓外無限大區(qū)域中的任意位置時(shí),界面裂紋尖端應(yīng)力強(qiáng)度因子的表達(dá)式.數(shù)值結(jié)果表明,隨著位錯(cuò)距離界面裂紋的位置越來越遠(yuǎn),裂紋尖端應(yīng)力強(qiáng)度因子的值越來越??;隨著界面裂紋開口角度的增大,裂紋尖端應(yīng)力強(qiáng)度因子的值先增大后減小.
583一維六方準(zhǔn)晶中界面裂紋與位錯(cuò)的交互作用_[]
關(guān)鍵詞:準(zhǔn)晶;界面裂紋;螺型位錯(cuò);應(yīng)力
2、強(qiáng)度因子;復(fù)變函數(shù)方法
中圖分類號(hào):O346.1 文獻(xiàn)標(biāo)識(shí)碼:A
Abstract:The interaction effects between a single circular interfacial crack and screw dislocation located inside the matrix were investigated for 1D hexagonal quasicrystal. Through applying the complex potential method, the closed form solutions of this proble
3、m were obtained. The degradation results are consistent with the conclusions in previous literature. The stress intensity factor at the crack tip was also derived. The results show that the stress intensity factor decreases with the increase of the distance between the dislocation and interfacial cr
4、ack. With the increase of the opening angle of the circular interfacial crack, the stress intensity factor increases firstly and then decreases.
Key words:quasicrystals; interfacial cracks; screw dislocations; stress intensity factor; complex variable method
1984年,Shechtman等人?l現(xiàn)準(zhǔn)晶.一直以來,準(zhǔn)晶以其獨(dú)特的
5、物理力學(xué)性能和未來良好的應(yīng)用前景,使其無論是在理論研究還是在實(shí)驗(yàn)觀察方面,都吸引著廣大研究者的關(guān)注[1-5].然而,準(zhǔn)晶復(fù)合材料中的缺陷問題,如位錯(cuò)、裂紋、夾雜等會(huì)極大地影響到材料的力學(xué)性能.
近些年來,越來越多的科研人員開始研究準(zhǔn)晶中的缺陷問題.Fan等[6]應(yīng)用復(fù)變函數(shù)的方法研究了一維六方準(zhǔn)晶中運(yùn)動(dòng)的Griffith裂紋問題;Wang 等[7]研究了十次準(zhǔn)晶中半無限裂紋與刃型位錯(cuò)的干涉效應(yīng)問題,并求得了裂紋尖端的應(yīng)力強(qiáng)度因子和應(yīng)變能釋放率的表達(dá)式;Hu等[8]研究了一維六方準(zhǔn)晶中螺型位錯(cuò)與圓形夾雜的彈性干涉問題,并揭示了位錯(cuò)力與相位子場(chǎng)彈性常數(shù)和聲子場(chǎng)相位子場(chǎng)耦合彈性常數(shù)之間的變化規(guī)
6、律.這些研究大多是針對(duì)單一缺陷問題或者單一準(zhǔn)晶材料中的缺陷問題,對(duì)于準(zhǔn)晶復(fù)合材料中缺陷之間的干涉效應(yīng)問題,報(bào)道的比較少.
本文研究了一維六方準(zhǔn)晶雙材料中單個(gè)圓弧形界面裂紋與基體中螺型位錯(cuò)之間的交互作用問題.運(yùn)用復(fù)變函數(shù)的解析延拓技術(shù)與奇性主部分析方法,獲得了該問題的封閉形式解.在得到界面裂紋尖端應(yīng)力強(qiáng)度因子的表達(dá)式后,討論了裂紋尖端應(yīng)力強(qiáng)度因子分別與裂紋開口角度、位錯(cuò)相對(duì)位置的變化規(guī)律.
1 問題的描述與求解
在一維六方準(zhǔn)晶中,當(dāng)缺陷(位錯(cuò)、裂紋)的幾何特征沿準(zhǔn)周期方向(z軸)無變化時(shí),其彈性問題可分解為2個(gè)相互獨(dú)立的問題[9].第一個(gè)問題是經(jīng)典彈性問題,已被充分研究過.因此
7、我們僅討論第二個(gè)反平面聲子場(chǎng)相位子場(chǎng)耦合問題,于是有:
4 結(jié) 論
本文研究了一維六方準(zhǔn)晶雙材料中單個(gè)圓弧形夾雜界面裂紋與基體中螺型位錯(cuò)之間的交互作用問題.運(yùn)用復(fù)變函數(shù)的解析延拓技術(shù)與奇性主部分析方法,獲得了該問題的封閉形式解.當(dāng)界面裂紋消失時(shí),所得的退化結(jié)果與已有文獻(xiàn)一致.
在得到界面裂紋尖端應(yīng)力強(qiáng)度因子的表達(dá)式后,討論了圓形晶體夾雜與準(zhǔn)晶基體的單個(gè)圓弧形界面裂紋的應(yīng)力強(qiáng)度因子分別與裂紋開口角度、位錯(cuò)相對(duì)位置的變化規(guī)律.隨著位錯(cuò)距離界面裂紋的位置越來越遠(yuǎn),裂紋尖端應(yīng)力強(qiáng)度因子的值越來越小;隨著界面裂紋開口角度的增大,裂紋尖端應(yīng)力強(qiáng)度因子的值先增大后減小,即存在一個(gè)特定的裂紋
8、開口角度,使得應(yīng)力強(qiáng)度因子的值達(dá)到最大值.
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