本文關(guān)鍵詞： 小尺度效應(yīng) 非均質(zhì)材料 多場載荷 孔洞愈合 熱動力學(xué)勢　出處：《上海交通大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：非均質(zhì)材料以其獨特的材料性質(zhì)隨位置變化的分布特性,在各種極端環(huán)境及多場載荷作用的工程結(jié)構(gòu)中得到廣泛應(yīng)用。本文以非局部彈性理論為基礎(chǔ),研究力、熱、電、磁多場載荷下考慮小尺度效應(yīng)的非均質(zhì)材料內(nèi)部的微觀損傷愈合規(guī)律。在建立材料性質(zhì)沿徑向指數(shù)分布的非均質(zhì)體內(nèi)孔洞動態(tài)收縮的力學(xué)模型后,利用非局部彈性理論得到非均質(zhì)體內(nèi)孔洞邊緣擴(kuò)散層中的應(yīng)變能,并結(jié)合晶格擴(kuò)散和化學(xué)位梯度變化規(guī)律求出非均質(zhì)晶體內(nèi)孔洞收縮速率和自愈時間的解析表達(dá)式。結(jié)果表明小尺度效應(yīng)可以通過增加晶體內(nèi)孔洞的收縮速率和減小內(nèi)孔洞愈合到穩(wěn)定的尺寸來有效的促進(jìn)非均質(zhì)晶體內(nèi)孔洞自愈;當(dāng)材料特性沿徑向的分布指數(shù)為1時將獲得最佳的內(nèi)孔洞收縮結(jié)果;適當(dāng)改變環(huán)境溫度變化和施加特定的電、磁場也能促進(jìn)內(nèi)孔洞自愈收縮;非均質(zhì)壓電體周圍的外加電勢會對其內(nèi)孔洞的收縮速率起到較大的影響。
[Abstract]:Non-homogeneous materials are widely used in engineering structures with various extreme environments and multi-field loads due to their unique distribution characteristics of material properties varying with location. This paper studies force, heat and electricity on the basis of non-local elastic theory. The microcosmic damage healing law of heterogeneous materials with small scale effect under multi-field magnetic loading. The dynamic shrinkage model of the pores in heterogeneous materials with radial exponential distribution of material properties is established. Using the nonlocal elastic theory, the strain energy in the diffusion layer at the edge of the hole in the heterogeneous body is obtained. The analytical expressions of shrinkage rate and self-healing time of pores in heterogeneous crystals are obtained by combining the law of lattice diffusion and chemical potential gradient. The results show that the small-scale effect can be achieved by increasing the shrinkage rate and decreasing the shrinkage rate of the pores in the crystals. The small inner cavity heals to a stable size to effectively promote the self-healing of the inner hole in the heterogeneous crystal; When the distribution index of material characteristics along the radial direction is 1:00, the optimum shrinkage of the inner cavity will be obtained, and the magnetic field can also promote the self-healing shrinkage of the inner hole by changing the ambient temperature and applying specific electricity. The external potential around the heterogeneous piezoelectric body will have a great effect on the shrinkage rate of the inner hole.
【學(xué)位授予單位】：上海交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TB303

【參考文獻(xiàn)】

相關(guān)碩士學(xué)位論文 前1條

1 劉穎;小尺度和壓電效應(yīng)下晶內(nèi)孔洞的愈合研究[D];上海交通大學(xué);2011年

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本文編號：1502811