Instability and friction

A review on the stability analysis of solids in unilateral and frictional contact is given. The presentation is focussed on the stability of an equilibrium position of an elastic solid in frictional contact with a fixed or moving obstacle. The problem of divergence instability and the obtention of a criterion of static stability are discussed first for the case of a fixed obstacle. The possibility of flutter instability is then considered for a steady sliding equilibrium with a moving obstacle. The steady sliding solution is generically unstable by flutter and leads to a dynamic response which can be chaotic or periodic. This dynamic response leads to the generation of stick–slip–separation waves on the contact surface in a similar way as Schallamach waves in statics. Illustrating examples and principal results recently obtained in the literature are reported. Some problems of friction-induced vibration and noise emittence, such as brake squeal for example, can be interpreted in this spirit. To cite this article: Q.S. Nguyen, C. R. Mecanique 331 (2003).     

Confined buckling of inextensible rods by convex difference algorithms

In this Note we present an approach to determine the local minima of a specific class of minimization problems. Attention is focused on the inextensibility condition of flexible rods expressed as a nonconvex constraint. Two algorithms are derived from a special splitting of the Lagrangian into the difference of two convex functions (DC). They are compared to the augmented Lagrangian methods used in this context. These DC formulations are easily extended to contact problems and applied to the determination of confined buckling shapes. To cite this article: P. Alart, S. Pagano, C. R. Mecanique 330 (2002) 819–824.     

由Lévy过程驱动的BSDE定义的一般非线性期望

本文研究了平凡可积随机变量的一类非线性期望f-期望.利用陈增敬推广g-期望的方法,扩张了f-期望的定义空间.     

一类广义Liénard系统解的有界性

获得了广义 Liénard系统dxdt=p(y) -F(x) ,　 dydt=-g(x) q(y)所有正半轨线有界的若干充分条件 ,推广改进了已有文献 [1— 1 2 ]中的相应结果 .     

Clifford分析中奇异积分的Poincaré-Bertrand置换公式

借助于多元复分析的思想，本文证明了Ｃｌｉｆｏｒｄ分析中奇异积分的Ｐｏｉｎｃａｒé－Ｂｅｒｔｒａｎｄ置换公式．     

正则局部Lipschitz函数可微性的几何条件

Ｂａｎａｃｈ空间的范数可微性可用它的单位球面来刻画．本文把这些范数可微性的几何条件推广到正则局部Ｌｉｐｓｃｈｉｔｚ函数情形．     

指数Lévy跳-扩散模型下欧式期权的COS定价方法

主要研究指数Lévy形式的跳-扩散模型下欧式期权的定价问题.首先,给出了模型在均值修正等价鞅测度下的风险中性特征函数;然后,基于特征函数给出了欧式期权的傅里叶COS定价方法,并对COS方法进行修正,得到了指数Lévy形式跳-扩散模型的期权定价公式;最后,通过数值实验和实证分析检验了COS定价方法有效性,结果表明COS方...     

任意阶F-Bézier基的一些基本性质

任意次的F-Bézier基统一了三角多项式空间上的C-Bézier基和双曲多项式空间上的H-Bézier基,我们证明这种基函数具有类似于基函数的优良性质,包括端点性质、对称性、升阶性质、线性无关性等,并且证明当形状参数趋于零时F-Bézier基收敛Bernstein基.     

The gerber-shiu expected discounted penalty function for Lévy insurance risk processes

In this paper,we study a general Lévy risk process with positive and negative jumps.A renewal equation and an infinite series expression are obtained for the expected discounted penalty function of this risk model.We also examine some asymptotic behaviors for the ruin probability as the initial capital tends to infinity.     

一种非本征光纤法布里-珀罗传感器的信号解调算法

给出了一种基于均方误差估计的非本征光纤法布里-珀罗(EFPI)传感器的腔长解调算法。在参量估计方面, 均方误差将估计子的方差和偏差结合在一起, 具有更高的估计精度和准确度。如果给出某一个真值的一系列估计子, 则具有最小均方误差的估计子比其他估计子更为有效。在非本征光纤法-珀传感器的腔长解调方面, 则实际腔长对应于腔长均方误差估计取最小值时的腔长估计子。对一个非本征光纤法-珀压力传感器的测试结果表明, 腔长解调分辨率为0.18 nm, 对应的压力分辨率可达2.99 kPa。与传统的解调算法相比, 通过该算法可在较宽的动态范围内获得高的解调分辨率, 并实现绝对腔长的解调。