国产bbaaaaa片,成年美女黄网站色视频免费,成年黄大片,а天堂中文最新一区二区三区,成人精品视频一区二区三区尤物

首頁> 外文學(xué)位 >Homogenization based damage models for monotonic and cyclic loading in three-dimensional composite materials.
【24h】

Homogenization based damage models for monotonic and cyclic loading in three-dimensional composite materials.

機(jī)譯：基于均質(zhì)化的三維復(fù)合材料單調(diào)和循環(huán)載荷損傷模型。

獲取原文
獲取原文并翻譯 | 示例
  • 摘要
  • 著錄項(xiàng)
  • 相似文獻(xiàn)
  • 相關(guān)主題

摘要

This dissertation develops a three dimensional homogenization based continuum damage mechanics (HCDM) model for fiber reinforced composites undergoing micromechanical damage under monotonic and cyclic loading. Micromechanical damage in a representative volume element (RVE) of the material occurs by fiber-matrix interfacial debonding, which is simulated using a hysteretic bilinear cohesive zone model. The proposed HCDM model expresses a damage evolution surface in the strain space in the principal damage coordinate system (PDCS). PDCS enables the model to account for the effect of non-proportional load history. The material constitutive law involves a fourth order orthotropic tensor with stiffness characterized as a macroscopic internal variable. Three dimensional damage in composites is accounted for through functional forms of the fourth order damage tensor in terms of components of macroscopic strain and elastic stiffness tensor. The HCDM model parameters are calibrated from homogenized micromechanical solutions of the RVE for a few representative strain histories. The proposed model is validated by comparing the CDM results with homogenized micromechanical response of single and multiple fiber RVEs subjected to arbitrary loading history. Finally the HCDM model is incorporated in a macroscopic finite element code to conduct damage analysis in structures. The effect of different microstructures on the macroscopic damage progression is examined through this study.;To efficiently simulate the dynamic response of heterogeneous microstructures, an assumed stress hybrid Voronoi Cell Finite Element Method (VCFEM) for stress wave propagation is developed. In the proposed formulation, stresses in the domain and compatible displacements at the element boundary are approximated independently. The inertia field is approximated in terms of stresses so as to satisfy the equilibrium a-priori. The weak forms of kinematics and traction reciprocity are obtained by minimization of the complementary variational principle. As stress wave is a local disturbance, localization and multi-resolution properties of the wavelet functions are exploited to adaptively enrich the stress functions locally near the wave front. At the outset, a stable, accurate, and computationally efficient adaptive computational framework is developed for micromechanical response of composites under impact loading. The effectiveness of the proposed method is demonstrated through comparison with conventional FEM packages.
機(jī)譯：本文針對(duì)纖維增強(qiáng)復(fù)合材料在單調(diào)和循環(huán)載荷作用下受到微機(jī)械損傷，建立了基于三維均質(zhì)化的連續(xù)介質(zhì)損傷力學(xué)模型。材料的代表性體積元素（RVE）中的微機(jī)械損傷是通過纖維-基體界面剝離而發(fā)生的，這是使用滯回雙線性內(nèi)聚區(qū)模型進(jìn)行模擬的。提出的HCDM模型在主損傷坐標(biāo)系（PDCS）中表示應(yīng)變空間中的損傷演化表面。 PDCS使模型能夠考慮非比例載荷歷史的影響。物質(zhì)本構(gòu)定律涉及具有剛性的四階正交各向異性張量，其特征是宏觀內(nèi)部變量。根據(jù)宏觀應(yīng)變和彈性剛度張量的分量，通過四階損傷張量的功能形式解釋了復(fù)合材料中的三維損傷。 HCDM模型參數(shù)是從RVE的均質(zhì)化微機(jī)械解決方案中針對(duì)一些代表性應(yīng)變歷史進(jìn)行校準(zhǔn)的。通過將CDM結(jié)果與承受任意載荷歷史的單纖維和多纖維RVE的均質(zhì)化微機(jī)械響應(yīng)進(jìn)行比較，驗(yàn)證了所提出的模型。最后，HCDM模型被并入到宏觀有限元代碼中，以進(jìn)行結(jié)構(gòu)的損傷分析。通過這項(xiàng)研究，研究了不同微觀結(jié)構(gòu)對(duì)宏觀損傷進(jìn)展的影響。為了有效地模擬異質(zhì)微觀結(jié)構(gòu)的動(dòng)力響應(yīng)，開發(fā)了一種假定的應(yīng)力混合Voronoi細(xì)胞有限元方法（VCFEM）來進(jìn)行應(yīng)力波傳播。在提出的公式中，區(qū)域中的應(yīng)力和單元邊界處的兼容位移是獨(dú)立估算的。慣性場(chǎng)根據(jù)應(yīng)力來近似，從而滿足平衡先驗(yàn)。運(yùn)動(dòng)學(xué)和牽引互易性的弱形式是通過最小化互補(bǔ)變分原理獲得的。由于應(yīng)力波是局部擾動(dòng)，因此利用小波函數(shù)的局部化和多分辨率屬性來自適應(yīng)豐富波前附近的應(yīng)力函數(shù)。首先，針對(duì)復(fù)合材料在沖擊載荷下的微機(jī)械響應(yīng)，建立了穩(wěn)定，準(zhǔn)確，計(jì)算高效的自適應(yīng)計(jì)算框架。通過與常規(guī)FEM軟件包進(jìn)行比較，證明了該方法的有效性。

著錄項(xiàng)

  • 作者

    Jain, Jayesh R.;

  • 作者單位

    The Ohio State University.;

  • 授予單位 The Ohio State University.;
  • 學(xué)科 Engineering Mechanical.
  • 學(xué)位 Ph.D.
  • 年度 2009
  • 頁碼 156 p.
  • 總頁數(shù) 156
  • 原文格式 PDF
  • 正文語種 eng
  • 中圖分類 機(jī)械、儀表工業(yè);
  • 關(guān)鍵詞

相似文獻(xiàn)

  • 外文文獻(xiàn)
  • 中文文獻(xiàn)
  • 專利
獲取原文

客服郵箱：kefu@zhangqiaokeyan.com

京公網(wǎng)安備：11010802029741號(hào) ICP備案號(hào)：京ICP備15016152號(hào)-6 六維聯(lián)合信息科技 (北京) 有限公司?版權(quán)所有

  • 客服微信

  • 服務(wù)號(hào)