刚粘塑性圆轴扭转和拉伸的组合变形

分析了不可压缩刚粘塑性圆轴扭转和拉伸的组合变形.作为特例,讨论了圆轴只承受拉伸和只承受扭转时的情况.     

考虑弯扭形变的薄壁箱形梁的非线性后屈曲

在大位移和扭转的前提下,通过一中等弯曲扭转的位移场描述了薄壁箱形梁在偏心载荷作用下的静稳定性问题.该非线性公式可用于分析简支薄壁箱形梁在不同载荷作用下的屈曲和后屈曲行为.采用伽辽金方法将非线性微分系统离散,并通过牛顿-拉普森增量迭代法求解得代数方程组.数值计算结果表明,当前屈曲位移不可忽略时,经典的横向屈曲预测是保守的...     

Organizing Filament of Small Amplitude Scroll Waves

We theoretically analyze the organizing filament of small amplitude scroll waves in general excitable media by perturbation method and explicitly give the expressions of coefficients in Keener theory.In particular for the excitable media with equal diffusion,we obtain a close system for the motion of the filament.With an example of the Oregonator Model,our results are in good agreement with those simulated by Windree.     

薄壁梁轴向碰撞下的动力弹性分析

对薄壁梁的轴向碰撞问题进行了理论分析．考虑具有非对称断面和弯曲初始缺陷的薄壁梁受质量轴向对心碰撞的情形，计及弯扭耦合、轴向惯性、横向惯性和扭转惯性的影响，建立了薄壁梁轴向碰撞下的动力学方程式．采用有限差分的方法对控制微分方程进行了求解．以槽形断面薄壁梁为例进行了算例计算和分析．分析中考虑梁的动力弹性屈曲问题，并对初始缺陷和碰撞速度的影响进行了讨论，得出了有意义的结论．     

汽车转向柱管花键端部的强度研究

转向柱管是汽车转向系统中的重要部件之一,文章通过对某厂生产的汽车转向柱管总成试件的扭转破坏试验研究,结果证明在转向柱管靠凹槽一侧花键端部,通过增加转向柱管外花键齿与方向盘中心内花键齿之间的非接触区间长度,可以提高转向柱管所承受的最大扭矩的重要结论,从而为转向柱管的设计提供了理论依据.     

对称扭杆弹簧系统隔振性能研究2000-04-03收稿.

对扭杆弹簧隔振系统的研究表明,扭臂的质量对系统的性能有比较大的影响.虽然系统可获得长的共振周期,但由于扭臂的质量不为零,地基振动的加速度被直接耦合进系统,从而严重地降低了系统的隔振性能.     

Superposition of large butt-end and coaxial torsional and axial shear deformations of homogeneous and fiber-reinforced thick-wall cylinders

A mathematical model of superposition of large butt-end and coaxial torsional and axial shear deformations of homogeneous and fiber-reinforced thick-wall cylinders is constructed. The macroscopic stresses of the reinforced material are additively determined by matrix stresses and by tensile or constrained compression stresses in the reinforcing fibers. The model is based on the numerical solution of two boundary-value problems, one of which corresponds to the butt-end torsion and the other to the coaxial torsion and axial shear. The boundary-value problem on joint deformations is solved with the use of the displacement field determined from the solution to the boundary-value problem on butt-end torsion. The results obtained by applying this method to homogeneous and axially-radially reinforced thick-wall cylinders subjected to butt-end torsion with subsequent coaxial torsion and axial shear are presented. __________ Translated from Mekhanika Kompozitnykh Materialov, Vol. 43, No. 4, pp. 465–492, July–August, 2007.     

Regular Twists: Replicating Coulomb’s Wire-Torsion Experiments

I discuss our replication of the wire-torsion experiments that Charles Augustin Coulomb (1736–1806) reported in a session of the Paris Académie des Sciences in 1784. I first explain the nature and purpose of the replication method and then apply it to an analysis of Coulomb’s experiments. I conclude by placing Coulomb’s presentation of his memoir into its specific historical contest.     

A Note on Mathematical Relationships Among Bond-Torsion Force Fields

A set of mathematical relationship between torsion potential functions such as trigonometric and Fourier series is presented herein. A harmonic approximation form is also introduced, and its stiffness constant is related to the parameters of trigonometric and Fourier series. Mathematical relationships between various force field parameters are presented in the form of conversion matrices.     

A Cheeger–Müller theorem for delocalized analytic torsion

We study the delocalized L ²-analytic torsion introduced by John Lott, and define the delocalized L ²-combinatorial torsion. By using the method of Bismut–Zhang, under the conditions of positive Novikov–Shubin invariants and finite conjugacy class, we get the Cheeger–Müller type relation between the delocalized L ²-analytic torsion and the delocalized L ²-combinatorial torsion.