An efficient rotation-free triangle and its application in cloth simulations

In this thesis, an efficient rotation-free (RF) triangle is proposed and applied to drape/cloth simulations in which the cloth often under large displacements and rotations. The RF model is a class of thin plate/shell computational models possessing only 3 translational degrees of freedom per director whilst their domains of influence are larger than their domains of integration. An important advantage of RF models is that they do not use rotational degrees of freedom and, thus, are not plagued by the complication in finite rotations. Among the quadrilateral and triangular RF models, the latter possesses no practical restriction on the nodal distribution and appears to be a good candidate for drape/cloth simulations. The geometrical linear formulation of the RF model is firstly considered. For straight beams and plates, the curvature is directly obtained through a complete quadratic interpolation of the transverse deflection. For linear curved beams and shells, the curvature change is again derived by the interpolation and the transverse deflection is through projection. The linear RF model is then extended to the geometrical nonlinear analyses by using the corotational framework as well as the small strain and small curvature assumptions. For the RF straight beam and plate, constant tangential bending stiffness matrices which do not need to be updated during the iterative solution process are derived. For the RF curved beam and shell, the bending energies and bending internal forces become a bit complicated. However, the tangential bending stiffness matrices can still be approximated by using the constant matrices as if they are initially straight/flat. The constant approximation exhibits negligible adverse effect on the convergence. Comparing with other exiting RF models, the present RF triangle is simple and physical yet its accuracy is competitive. In its application to static drape simulations, realistic drape configurations with obvious folds are predicted. The RF beam is extended to consider static and dynamic analyses of cable structures. Under the same nodal distributions, the present RF model can tolerate larger load increment and time step in static and explicit dynamic analyses, respectively, with respect to the two-node C0beam finite element model. For virtual sewing and dynamic cloth simulations, an integrated system is developed by synergizing the RF triangle, explicit time integration, adaptive remeshing, collision handling, human body modeling, sewing forces and a supplementary bending energy to suppress the non-physical sharp fold formation. The predicted steady-state configurations of the garments after sewing appear to be realistic and agree with our daily perception. The predictions for cloth dynamic deformations on human body model also look realistic and natural. This thesis proposes a simple and efficient rotation-free triangle which is especially suitable for the problems involving large displacements and rotations. Its application in drape/cloth simulations and integration of various techniques in cloth simulations are explored. The present study is of significance in cloth simulations.published_or_final_versionMechanical EngineeringDoctoralDoctor of Philosoph

不同集流方式下对称双阴极固体氧化物燃料电池的电-化-热-力数值模拟及失效分析

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Numerical Simulations of Current and Temperature Distribution of Symmetrical Double-Cathode Solid Oxide Fuel Cell Stacks Based on the Theory of Electric-Chemical-Thermal Coupling

国家重点研究开发项目No(2018YFB1502600);国家自然科学基金重点项目No(11932005);宁波市重大攻关项目No(2018B10048);浙江省能源集团有限公司科技项目资助No(ZNKJ-2018-008)通讯作者:朱建国,官万兵E-mail:[email protected];[email protected]:ZHUJian-guo,GUANWan-bingE-mail:[email protected];[email protected]. 江苏大学土木工程与力学学院,江苏 镇江2120132. 中国科学院宁波材料技术与工程研究所,浙江 宁波 3152013. 同济大学航空航天工程与力学学院,上海 2000924. 哈尔滨工业大学（深圳）理学院,广东 深圳5180555. 浙江浙能技术研究院有限公司,浙江 杭州 3111211. Faculty of Civil Engineering and Mechanics, Jiangsu University, Zhenjiang 212013, China2. Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China3. School of Aerospace Engineering and Applied Mechanics, Tongji University, Shanghai 200092, China4. School of Science, Harbin Institute of Technology, Shenzhen 518055, China5. Zhejiang Energy Technology Research Institute Company Co. Ltd, Hangzhou 311121, Chin