低周疲劳随机损伤过程的有限元模拟

讨论了一种低周疲劳下随机损伤演变过程 数值模拟方法，借助于Ｌｅｍａｉｔｒｅ＆Ｄｕｆａｉｌｌｙ给出的代表性体元的微观力学模型，建立了损伤与微裂纹尺寸的关系，采用随机初始损伤反映材料中固的的微缺陷，将所得模型与有限元结合对低周疲劳损伤过程进行了数值模拟。     

融合MEMS-IMU信息的亚像素相关跟踪方法

结合图像制导武器的工程应用,提出了一种融合微机电系统(Micro-Electro-Mechanical System, MEMS)-惯性测量单元(Inertial Measurement Unit,IMU)信息的亚像素相关跟踪方法。该方法采用基于速率测定的误差补偿方法对MEMS-IMU的测量误差进行补偿,以实现MEMS-IMU信息与图像数据的异质数据融合,同时采用基于模板插值的亚像素相关跟踪算法来提高跟踪精度。结果表明,该方法不仅可以较好地解决目前单靠图像信息提升图像跟踪精度时所面临的算法实时性与复杂度之间的冲突问题,而且还可以有效提升动基座下的图像跟踪精度。     

表面裂纹平板应力强度因子的杂交应力元-线弹簧模型方法

本文采用基于杂交应力元和线弹簧模型相结合的方法,计算表面裂纹平板的应力强度因子。结果表明,本文解和三维有限元解吻合很好,与基于位移元和线弹簧模型相结合的解相比,具有更高的精度和较宽的适用范围。     

断裂分析中的随机有限元方法

以单边裂纹板为例给出计算断裂参数:J(J积分)、δ(裂纹张开位移)、Δc(由裂纹引起的上、下端面的相对位移)、θc(由裂纹引起的上、下端面的相对转角)及其对基本随机变量变化率的随机有限元方法.     

On Einsteinian Manifolds Admitting Orthogonal Families of Totally Umbilical Hypersurfaces

The aim of the present paper is to study globally the Riemannian manifold admitting two or more mutually orthogonal families of totally umbilieal hypersurfaces of which each is Einsteinian. This paper consists of four parts: (i) to establish anew the canonical form of the metric of (M,g)admitting p (p≥2) families of mutually orthogonal totally umbilical hypersurfaces from the standpoint of global differential geometry; (ii) to prove in a n-dimensional (n>2) Einsteinian manifold E_n of nonvanishing scalar curvature there doesn't exist one family of compact totally geodesic Einsteinian hypersurfaces (Theorem I); (iii) to prove in a n-dimensional (n≥5) Einsteinian manifold E, of nonnegative scalar curvature there don't exist two orthogonal families of totally umbilical but not geodesic complete Einsteinian hypersurfaces (Theorem II); (iv) to show that a n-dimensional (n≥5) Riemannian manifold of negative constant scalar curvature admitting p (p≥3) mutually orthogonal families of compact, totally umbili