箱形截面剪力滞理论综述

综述了近几十年国内外研究箱形截面剪力滞问题的主要理论和成果,评价了各种研究方法的适用性和局限性,并提出了今后有待进一步研究的方向,为非线性剪力滞问题的研究提供了理论基础。     

板中正交静应力与Lamb波波速关系探讨

在静应力产生的位移是有限位移,波产生的位移是无限小位移的假设前提下,用非线性声弹性理论,导出了正交静应力作用下的各向同性超弹性体的等效弹性常数．进而探讨了正交静应力与Lamb波波速的关系．得出了一些有实用价值的结论。可为Lamb波的应力测量提供理论基础。     

Geometrically Non-Linear Analysis of Adhesively Bonded Double Containment Corner Joints

In cases where adhesively bonded joints may experience large displacements and rotations whilst the strains remain small, although all joint members behave elastically the small strain-small displacement (SSSD) theory cannot correctly predict the stresses and deformations in the adhesive joint members. Previous studies have shown that the small strain-large displacement theory considering the non-linear effects of the large displacements in the stresses and deformations has to be used in the analysis of adhesively bonded joints. In this study, the geometrical non-linear analysis of an adhesively bonded double containment corner joint was carried out using the incremental finite element method based on the small strain-large displacement (SSLD) theory. The objective of the study was to determine the effects of the large displacements on the adhesive and adherend stresses of the corner joint. Therefore, the corner joint was analysed for two different loading conditions; a compressive applied load, P_x, at the free end of the horizontal plate and one normal to the plane of the horizontal plate, P_y. The plates, support and adhesive layer were assumed to have elastic properties. In practice, the adhesive accumulations, called spew fillets, arising around the adhesive free ends were taken into account in the analysis since their presence results in a considerable decrease in the peak stresses around the free ends of the adhesive. The SSLD and SSSD analyses showed that the stress concentrations occurred around the free end of the adhesive, thus at the adherend (slot) corners inside the right vertical and the lower horizontal adhesive fillets, and inside the left vertical and the upper horizontal adhesive fillets for the loading conditions P_x and P_y, respectively. In addition, the plate regions around the adherend (slot) free ends along the outer fibres of the vertical and horizontal plates undergo very high stress concentrations. The SSLD analysis predicted a non-linear effect in the displacement and stress variations at the critical adhesive and plate locations, whereas the SSSD analysis showed their variations were lower and proportional to the applied incremental load. This non-linear effect became more evident for the loading condition P_x, whereas both analyses predicted very close displacement and stress variations in the adhesive fillets and in the horizontal plate for the loading condition P_y. As a result, the geometrical non-linear behaviour of the corner joint is strictly dependent on the loading condition and the large displacements affect the stress and deformation states in the joint members, and result in higher stresses than those predicted by the SSSD theory.     

保实光纤──用PCVD工艺研制的新一代色散位移光纤

采用PCVD工艺研制的保实光纤（POSH）,光学性能和几何性能好,在工作窗口有小的正色散,可以有效地抑制非线性效应,适用于高速度、大容量、长距离的光纤通信系统。     

基于神经网络的AD590温度传感器非线性校正技术

针对AD590温度传感器的非线性校正问题,在双点校正基础上提出一种新的校正方法——神经网络法。此神经网络采用1-3-2-1结构,节点函数采用S型函数,实际结果表明,在-10～ 100℃较宽的温度范围内温度误差小于0．05℃。     

Adaptive control in the presence of saturation non-linearity

Saturation non-linearities are perhaps the most commonly present type of non-linearities in dynamic systems. It is therefore important for the controller present to function satisfactorily in the presence of input saturation. In this paper we present an adaptive controller which leads to satisfactory performance in the presence of magnitude saturation of the control input. For both continuous time and discrete time plants, the adaptive controller is shown to result in global stability if the plant is open loop stable and minimum phase, and local stability otherwise. Robustness properties of the resulting adaptive controller are established. The performance is verified through experimental results obtained from adaptive control of a precision machine tool axis. © 1997 by John Wiley & Sons, Ltd.     

负泊松比蜂窝芯非线性等效弹性模量研究

设计并加工了一种负泊松比蜂窝结构,采用柔性悬臂梁模型,对蜂窝壁板大变形条件下的弯曲变形进行分析,给出了蜂窝芯面内等效弹性模量理论计算公式。通过有限元仿真和力学实验的对比分析,验证了非线性理论计算公式的正确性。得出了等效弹性模量的非线性特性及相同方向和不同方向弹性模量的变化特性。研究结果为柔性蜂窝芯层的工程实用化提供了参考。     

轴力对巨型钢柱滞回性能的影响分析

通过双重非线性有限元程序ANSYS5.7,分析了不同轴压比对人字形支撑和X形支撑的两种巨型钢柱滞回性能的影响规律。并针对地震作用下实际结构中巨型柱可能出现的受力状态,讨论了轴力和水平剪力同时增加或减小时巨型钢柱的滞回特性。     

一种改进BP网络及其在智能传感器非线性校正中的应用

主要分析了神经网络存在的一些缺陷,研究了一种改进BP神经网络学习算法的相关技术,设计并实现了一种改进型BP神经网络算法,并将其应用于智能传感器的非线性自校正系统。通过在某无人机机载高度传感器上试验研究,证明了这种算法的可靠性、先进性、稳定性。     

基于Kriging近似模型的轿车翼子板冲压工艺优化

近似模型法是目前最有代表性的高效优化方法。因基于多项式的近似模型很难满足板料成形的高度非线性,所以基于Kriging近似模型法,以翼子板的各拉深筋单位长度上所受的拉深筋阻力及压边力为设计变量,以成形后板料的最小厚度为响应量,建立近似模型。通过自适应模拟退火算法寻优,并约束最小厚度的变化范围,提高优化效率。通过优化,成形后板料的最小厚度从0．521mm增加至0．544mm,消除了局部破裂趋势,有效地改善了翼子板的成形质量。研究表明,Kriging近似模型法对板料成形有较高的精度。