用样条函数法分析旋转组合壳

本文采用不等距三次Ｂ样条函数对旋转壳在整体坐标下的位移进行插值，给出了周向插值所必需满足的周期性条件，采用罚单元法，给出了组合壳体在整体坐标下的协调关系，与惯用方法相比，这种方法简单明了直观性强，易于接受。文末给出了算例。     

用样条函数法分析旋转组合壳

本文采用不等距三次Ｂ样条函数对旋转壳在整体坐标下的位移进行插值，给出了周向插值所必需满足的周期性条件，采用罚单元法，给出了组合壳体的整体坐标下的协调关系，与惯用方法相比，这种方法简单明了直观性强，易于接受。文末出出了算例。     

薄板结构的安定优化设计

本文通过对薄板的Ｂ样条函数插值及结构中残余应力场的温度参数模拟，研究了薄板安定分析的样条有限元列式，在分析结构安定分析的数学规划列式的基础上，解决了薄板结构在给定可变载荷作用下的安定最小厚度设计问题。由于温度参数的引用，使得研究的问题的自由度大幅度减少。算例表明本文所提出的方法及所编程序的可行和有效。     

薄板结构的安定优化设计

本文通过对薄板的Ｂ样条函数插值及结构中残余应力场的温度参数模型，研究了薄板安定分析的样条有限元列式，在分析结构安定分析的数学规划列式的基础上，解决了薄板结构在给定可变载荷作用下的安定最小厚度设计问题。由于温度参数的引用，使得研究的问题的自由度大幅度减少，算例表明本文所提出的方法及所编程序的可行和有效。     

动态优化中的灵敏度分析研究

本文利用模态分析技术和向量原理,推导出特征值、特征向量和稳态响应幅值随设计变量变化的灵敏度分析式。对于很难求刚度矩阵的结构,推导出直接以柔度矩阵表达的灵敏度公式,文中给出的一个四层框架结构的算例和试验结果,表明了有关灵敏度算式的正确性。     

基于SVM回归的圆柱壳体抗脉冲强度预估模型

在小子样结构响应试验数据样本的基础上,利用支持向量机回归的方法模拟了圆柱壳体动态极限应变峰值同壳体几何尺寸和外加脉冲载荷大小的非线性函数关系,同时通过改进的模拟退火单纯形混合算法优化了支持向量机的性能参数,并将支持向量机回归分析的预测性能同BP人工神经网络方法做了比较,验证了具有优化性能参数组合的支持向量机在小样本条件下更好的预测和推广能力. 最后,从支持向量机回归模型导出了大尺寸圆柱壳体抗脉冲载荷的强度极限同自身几何尺寸的多元函数关系,从而为该类型壳体设备抗脉冲载荷的强度分析提供了一个可借鉴的预估模型. 研究结果表明了支持向量机在机械结构的强度预估和可靠性分析等力学领域具有广泛的应用前景.      

应变强化模型的安定准则研究

基于Melan经典的安定理论和von Mises屈服准则,建立了塑性应变强化条件下结构安定的数学模型,根据与时间无关的应力场的特性,对结构中与时间无关的应力场进行了合理的数学变换,将其与载荷变化系数联系起来,推导出与其对应的结构安定极限范围的表达式,给出塑性应变强化模型安定性存在的简化条件.该结论有利于简化应变强化条件下结构的安定分析.     

双层旋转壳流固耦合振动有限元分析

本文用旋转壳体元和流体元分析了双层旋转壳体流固耦合振动特性，基于Ｎｏｖｏｚｈｉｌｏｖ壳体理论、水弹性理论以及Ｈａｍｉｌｔｏｎ变分原理推导出耦合系统运行方程，计算结果与实测值比较表明本分析方法有较好的精度。     

块体理论赤平解析法在锦屏二级水电站皮带机隧洞稳定分析中的应用

在小子样结构响应试验数据样本的基础上,利用支持向量机回归的方法模拟了圆柱壳体动态 极限应变峰值同壳体几何尺寸和外加脉冲载荷大小的非线性函数关系,同时通过改进的模拟 退火单纯形混合算法优化了支持向量机的性能参数,并将支持向量机回归分析的预测性能同 BP人工神经网络方法做了比较,验证了具有优化性能参数组合的支持向量机在小样本条件下 更好的预测和推广能力. 最后,从支持向量机回归模型导出了大尺寸圆柱壳体抗脉冲载荷的 强度极限同自身几何尺寸的多元函数关系,从而为该类型壳体设备抗脉冲载荷的强度分析提 供了一个可借鉴的预估模型. 研究结果表明了支持向量机在机械结构的强度预估和可靠性分 析等力学领域具有广泛的应用前景.     

全局分析的胞参照点映射迭代方法：理论及多尺度参照技术

胞参照点遇射迭代方法，建立了一个胞参照系来识别状态空间中的子区（胞）装配了特性函数后，胞纱就可以作为者和记录者由通过一佣子区的轨道信息去引出此子区的局部动力学，可以在保持点映射的精度，大大减少计算量。文中给出方法的理论基础和多尺度胞参照技术，后者用来实用时优化胞参照系，最后给出一个例子，示出本法不只可以提高吸引域的精度和效率，还有探查其他动力特性的潜力。     

The 7th International Conference on Fluid Mechanics May 24-27,2015,Qingdao,China

正http://www.icfm7.org First Announcement and Call for PapersThe objective of International Conference on Fluid Mechanics(ICFM)is to provide a forum for researchers to exchange new ideas and recent advances in the fields of theoretical,experimental,computational Fluid Mechanics as well as interdisciplinary subjects.It was successfully convened by the Chinese Society of Theoretical and Applied Mechanics(CSTAM)in Beijing(1987,     

INFORMATION FOR CONTRIBUTORS

Contributions： The Journal, Acta Mechanica Solida Sinica, is pleased to receive papers from engineers and scientists working in various aspects of solid mechanics. All contributions are subject to critical review prior to acceptance and publication.     

基于鲁棒滤波的捷联导引头视线角速度估计方法

针对捷联导引头无法直接获取视线角速度等信息的问题,研究了鲁棒滤波在大气层外飞行器捷联导引头视线角速度估计中的应用。为了建立非线性滤波估计模型,考虑目标视线角速度的慢变特性,采用一阶马尔科夫模型建立了状态方程;推导了视线角速度的解耦模型,并建立了量测方程;考虑到实际应用中存在系统噪声统计特性失准的问题,基于Huber-Based鲁棒滤波方法,设计了视线角速度滤波器,并完成了基于Huber-Based滤波方法和扩展卡尔曼滤波方法的数学仿真。仿真结果表明Huber-Based滤波方法的视线角、视线角速度及视线角加速度估计精度分别达到0.1140'、0.1423'/s、0.0203'/s2,而扩展卡尔曼滤波方法的视线角、视线角速度及视线角加速度估计精度仅分别为0.6577'、0.6415'/s、0.0979'/s~2。仿真结果证明了该方法可以有效地估计出相对视线角速度等信息,并且在非高斯噪声的条件下,依然可获得较高的估计精度,具有一定的鲁棒性。     

Guide for authors

正Each of the sections below provides essential information for authors.We recommend that you take the time to read them before submitting a contribution to Acta Mechanica Sinica.We hope our guide to authors may help you navigate to the appropriate section.How to prepare a submission This document provides an outline of the editorial process involved in publishing a scientific paper in Acta Mechanica     

Use specification of multiscale materials for life spanned over macro-, micro-, nano-, and pico-scale

Multiscale material intends to enhance the strength and life of mechanical systems by matching the transmitted spatiotemporal energy distribution to the constituents at the different scale, say—macro, micro, nano, and pico,—, depending on the needs. Lower scale entities are, particularly, critical to small size systems. Large structures are less sensitive to microscopic effects. Scale shifting laws will be developed for relating test data from nano-, micro-, and macro-specimens. The benefit of reinforcement at the lower scale constituents needs to be justified at the macroscopic scale. Filling the void and space in regions of high energy density is considered.Material inhomogeneity interacts with specimen size. Their combined effect is non-equilibrium. Energy exchange between the environment and specimen becomes increasingly more significant as the specimen size is reduced. Perturbation of the operational conditions can further aggravate the situation. Scale transitional functions and/or f_j/j+1 are introduced to quantify these characteristics. They are represented, respectively, by , and (f_mi/ma,f_na/mi,f_pi/na). The abbreviations pi, na, mi, and ma refer to pico, nano, micro and macro.Local damage is assumed to initiate at a small scale, grows to a larger scale, and terminate at an even larger scale. The mechanism of energy absorption and dissipation will be introduced to develop a consistent book keeping system. Compaction of mass density for constituents of size 10⁻¹², 10⁻⁹, 10⁻⁶, 10⁻³ m, will be considered. Energy dissipation at all scales must be accounted for. Dissipations at the smaller scale must not only be included but they must abide by the same physical and mathematical interpretation, in order to avoid inconsistencies when making connections with those at the larger scale where dissipations are eminent.Three fundamental Problems I, II, and III are stated. They correspond to the commonly used service conditions. Reference is made to a Representative Tip (RT), the location where energy absorption and dissipation takes place. The RT can be a crack tip or a particle. At the larger size scales, RT can refer to a region. Scale shifting of results from the very small to the very large is needed to identify the benefit of using multiscale materials.     

Impact non-pénétrant sur le thorax : influence de la courbure sur la propagation des ondesNonpenetrating impact on the thorax: influence of curvature on wave propagation

Theoretical studies of the propagation of impact waves through the thorax are needed to improve the design of bulletproof jackets and blast protections (Fung in ‘Biomechanics Motions, Flow, Stress, and Growth’, Springer-Verlag, 1990; Cooper et al., J. Trauma 40 (1996) S38–S41). The influence of the weak acoustic coupling at the interface between the thoracic wall and the lung were described in (Grimal et al., C. R. Acad. Sci. IIB 329 (2001) 655–662); in this work, we study, within the frame of elastodynamics and with an approximate analytical method, the effects of the curvature of this interface. Results are given in terms of strain energy for the pressure wave, transmitted or converted. Focalisation of energy in the medium representing the lung is important for curvatures measured in humans. To cite this article: Q. Grimal et al., C. R. Mecanique 330 (2002) 569–574.     

Vérification expérimentale de la relation de réciprocité d'Onsager pour l'électro-osmose et l'électro-filtration dans une argile naturelleExperimental verification of the Onsager's reciprocal relations for electro-osmosis and electro-filtration phenomena on a saturated clay

This Note is devoted to the experimental verification of the Onsager's reciprocal relations in the particular case of electro-osmosis and electro-filtration. A special set up has been designed to carry out the measurements of both the electro-osmotic permeability and the streaming potential. This has been performed by using a natural material i.e., saturated kaolinite. To cite this article: K. Beddiar et al., C. R. Mecanique 330 (2002) 893–898.