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631.
Geometric structures of Cosserat or micropolar continuum are discussed based on geometric objects in a non-Riemannian space. A microrotation is described in a microscopic level than a macroscopic displacement level. In this case, a microscopic rotation can be expressed as a nonlocal internal variable attached to each point in a generalized Finsler space. Such non-local hierarchy is geometrically realized by using a second-order vector bundle viewpoint. Then, two kinds of torsion tensor in the second-order vector bundle are obtained. One is characterized by the macroscopic displacement. The other is characterized by the microscopic rotation. These torsion tensors are equivalent to nonintegrability conditions for multivalued macroscopic displacement and microscopic rotation. Especially, a path dependency of the displacement and the microscopic rotation is represented by a non-vanishing condition of torsion tensors. Moreover, the concept of non-locality of the Finsler geometry implies that the approach of higher-order geometry is applicable to a finite deformation in nonlinear mechanics. The singularity given by the multivalued function is also described as a boundary value problem. An application of the generalized Finsler geometry to a gradient theory is also discussed. 相似文献
632.
采用有限元程序ABAQUS进行仿真分析,探讨了钢框架节点的非线性连接性能。针对几种典型节点,包括焊接连接、外伸式端板螺栓连接、平齐式端板螺栓连接、双腹板顶底角钢连接等,分别建立了相应的精化有限元分析模型,实现了结构非线性行为的真实再现和连接性能的准确评估。数值结果还给出了钢框架节点的弯矩-相对转角、弯矩-剪切转角及弯矩-节点转角三种关系曲线,并针对弯矩-节点转角曲线进行了回归分析,从而得到了四种钢框架节点的弯矩-节点转角关系式。建立的有限元分析模型可真实地模拟钢框架节点的非线性行为,分析得到了半刚性节点弯矩-转角关系的一般规律,可为钢框架梁柱连接节点的计算理论和设计方法提供重要参考和依据。 相似文献
633.
634.
Takashi Fukutomi Hiroki Oomori Yoshibumi Sugito 《Journal of polymer science. Part A, Polymer chemistry》1996,34(13):2729-2735
Poly(methyl methacrylate) microgels covered with poly(hydroxyethyl methacrylate) thin layer was dispersed in poly(vinyl alcohol) matrix. Homogeneous and regular arrangement of the microgel particles was suggested by Bragg diffraction for the films prepared by varying the PVA/microgel ratio (from 6/4 to 3/7 (w/w)). It was proved that the regular arrangement and connection of the microgels by seeded polymerization in poly(vinyl alcohol) were possible. © 1996 John Wiley & Sons, Inc. 相似文献
635.
The authors study the geometry of lightlike hypersurfaces on manifolds (M, c) endowed with a pseudoconformal structure c = CO(n – 1, 1) of Lorentzian signature. Such hypersurfaces are of interest in general relativity since they can be models of different types of physical horizons. On a lightlike hypersurface, the authors consider the fibration of isotropic geodesics and investigate their singular points and singular submanifolds. They construct a conformally invariant normalization of a lightlike hypersurface intrinsically connected with its geometry and investigate affine connections induced by this normalization. The authors also consider special classes of lightlike hypersurfaces. In particular, they investigate lightlike hypersurfaces for which the elements of the constructed normalization are integrable. 相似文献
636.
Radim Bêlohlvek 《Mathematical Logic Quarterly》1999,45(4):497-504
The concept of Galois connection between power sets is generalized from the point of view of fuzzy logic. Studied is the case where the structure of truth values forms a complete residuated lattice. It is proved that fuzzy Galois connections are in one-to-one correspondence with binary fuzzy relations. A representation of fuzzy Galois connections by (classical) Galois connections is provided. 相似文献
637.
王如山 《纯粹数学与应用数学》2000,16(1):54-58
利用文「1」的方法及Simons型公式对空间形式中具有平行非退化极小截面曲面进行了研究,从而将文「1」中一系列定理推广到2+P维空间形式中。 相似文献
638.
双棒串接Nd3+:YAG激光器 总被引:4,自引:2,他引:2
根据测量的单根Nd3+:YAG棒的热焦距,利用ABCD传输矩阵计算了双棒串接的几种腔型的稳定参量,给出了能够满足高功率、高稳定性激光输出的稳定腔型,实验结果与理论分析基本相符. 相似文献
639.
台阶式加筋土挡墙的原型试验研究 总被引:1,自引:0,他引:1
对一座台阶式钢筋混凝土串联拉筋加筋土挡墙的筋带应力、土侧向压力、土竖向压力及挡墙变形进行了实测和分析, 所得结论可供设计类似支挡结构时参考。 相似文献
640.
Howard Osborn 《Acta Appl Math》2001,66(2):209-210
An alternative construction of Riemann curvature appeared in Acta Appl. Math. 59 (1999), 215–227, with a promise of a short direct proof of its symmetries. The present Section 5 repairs a flaw in the original Section 5, with the promised proof. 相似文献