有应力史差非匀质截面轴心受压杆的性能研究

对有应力史差、非匀质、非线弹性的轴心受压构件进行了理论分析和试验研究，初步揭示了此类构件的受力特点．理论分析和试验表明：此类构件截面承载力不是各部分材料承载力的简单叠加；承载力和截面破坏控制点因截面上材料的本构关系的变化和应力史差而发生改变．     

偏心率效应对金属圆柱管轴压性能的影响

用含有偏心率因子的直链塑性铰叠缩模型来分析金属圆柱管轴向压缩能量吸收，根据能量原理推导了瞬时载荷，从而获得压缩过程的载荷-位移曲线．讨论了偏心率对平均压缩载荷和载荷-位移曲线形貌的影响．实验结果与模型分析符合得很好．     

轴压作用下充液圆柱壳屈曲的实验研究

本文从实验及理论两个方面对充满液体的圆柱壳在轴向压力作用下液体内压的变化进行了实际测试及理论定性分析．采用薄壳理论分析了屈曲前液体内压随轴向压力的变化规律，讨论了壳材料、几何参数及边界约束对内压的影响．通过实验实际测定了内压随轴向压力的变化规律．通过实验手段测定了充满液体的圆柱壳临界载荷、屈曲模态，讨论了充满液体的圆柱壳的承载能力等问题．     

Ultrasonic characterization of point defects induced by cross slip under pure shear

Longitudinal wave velocity is used to characterize the point defects in crystalline solids. High purity Al single crystal was selected for both the finite element analysis and experimental work. Since the jog motions of dislocations caused by intersected slides such as cross slips induce point defects, the total amount of cross slips was calculated instead of calculating directly from the point defects. The effect of crystal orientations on total amount of cross slips under pure shear was also investigated via the finite element method. The result suggest that if the initial shear stress direction is located at the inner side of stereographic triangle, only single slip activities occurred at the beginning of plastic deformation and no effects due to point defects were present. However, as the shear stress direction rotates along the slip direction, point defects are induced by cross slips between primary and secondary slip systems due to work-hardening. This phenomenon was then examined by measuring longitudinal wave velocity changes propagating in Al single crystal subjected to the combination loads of equi-biaxial tension and compression (a pure shear state). Good qualitative agreement between the finite element result and measured data suggest that the longitudinal wave velocity can be used as an index to characterize point defects in crystalline materials.     

水平圆管中受压扭作用管桩屈曲后的解析解

首先建立了考虑自重、受水平圆管约束的管柱在压担组合作用下的屈曲方程：此方程为四阶强非线性常微分方程，难以直接精确求解；通过管柱的正弦屈由分析，找到了方程中的小参数；利用小参数摄动法求解了强非线性屈曲方程，得到了管柱螺旋屈曲后的实际屈曲构形解析解，由此可进一步得到管柱发生螺旋屈曲的临界载荷；所得解析结果与数值计算结果及本文结果退化后与文献中的相关结果比较都有良好的一致性．     

An engineering approach to blade designs for low to medium pressure rise rotor-only axial fans

Low to medium pressure rise axial fan equipment of the arbitrary vortex flow rotor-only type is widely used in industrial and commercial applications, with many of the installations and rotor designs being far from optimum. Complex computational methods exist for analyzing flows in, for example, high-speed axial flow compressors with multistage blade rows; however, the designers and manufacturers of low-speed, general-purpose axial flow fan equipment have been reluctant to embrace this technology. A simpler yet reliable design technique is presented that allows this category of ducted axial fan rotors, in the presence of swirl-free inlet flow, to be designed to achieve a specified duty with sufficient accuracy for engineering purposes. Practical blade design recommendations and limits, similar to those that exist for free vortex flow axial rotors, have been established for the arbitrary vortex flow rotor-only case.

The technique employs a straightforward engineering approach to arbitrary vortex flow axial fan rotor design, and the equation set can be solved by using relatively simple numerical methods. Estimates of pressure rise and shaft power characteristics for a proposed fan/rotor design can be computed and the design loop iterated until an acceptable set of blade parameters is identified. It is also possible to analyze the performance of an existing axial fan installation as a prelude to the design of a more efficient and effective replacement rotor.

Experimental data used in validating the design and analysis techniques are also presented. These data include comprehensive Cobra pressure probe surveys of local flow parameters downstream of three different low boss ratio, low solidity, arbitrary vortex flow rotors (all with circular arc camber line type blades) as well as fan performance characteristics for one of the experimental rotors configured as a direct-exhaust fan unit. Installation-dependent factors such as direct-exhaust losses and tip clearance effects are also examined. The analytical technique is shown to provide acceptable estimates of fan/rotor pressure rise performance and shaft power characteristics over a moderately wide range of blade angles and operating conditions.     

充满水的金属圆柱壳经受轴向撞击时屈曲过程的实验研究

本文报道了五种规格充满水的圆柱壳经受大质量低速度轴向撞击作用时屈曲过程的实验结果。研究表明由于液体的存在，圆柱壳的屈曲模态呈轴对称型的环带波纹，整个撞击过程可以明显地分为振荡的动力加载、平稳发展的后屈曲和迅速下降的弹性卸载三个阶段。并讨论了试件壁厚和高度等几何参数对其屈曲性能的影响。     

轴向扩散下简支饱和多孔弹性梁的大挠度分析

基于多孔介质理论和弹性梁的大挠度理论,并考虑轴向变形,在孔隙流体仅沿轴向扩散的假设下,建立了微观不可压饱和多孔弹性梁大挠度弯曲变形的一维非线性数学模型.在此基础上,忽略饱和多孔弹性梁的轴向应变,并利用Galerkin截断法,研究了两端可渗透的简支饱和多孔弹性梁在突加横向均布载荷作用下的拟静态弯曲,给出了饱和多孔梁弯曲时挠度、弯矩和轴力以及孔隙流体压力等效力偶等沿轴线的分布曲线.揭示了大挠度非线性和小挠度线性模型的结果差异,指出大挠度非线性模型的结果小于相应小挠度线性模型的结果,并且这种差异随着载荷的增大而增大.计算表明:当无量纲载荷参数q>5时,应该采用大挠度非线性数学模型进行研究.     

STUDY OF AXIAL VELOCITY IN GAS CYCLONES BY 2D-PIV, 3D-PIY, AND SIMULATION

The axial velocity distribution in a gas cyclone has been examined with two-dimensional particle image velocimetry (2D-PIV) and three-dimensional particle image velocimetry (3D-PIV) experiments in this study. Due to the limitation of 2D-PIV configuration, the contamination generated by the strong tangential velocity in the cyclone can be registered in the axial velocity detected by 2D-PIV. Efficient methods are proposed in this work to remove this contamination. The contamination-removed 2D-PIV data agree well with 3D-PIV results. The distributions of the axial velocity are also computed by the Reynolds stress model (RSM) and verified using the PIV experimental results. Reasonable agreements are obtained.     

柱壳在轴向冲击载荷作用下动态塑性屈曲的实验研究

圆柱壳的动态塑性屈曲问题的研究主要是集中在屈曲模态方面，至于屈曲的临介载荷与临介时时间则研究的较少，ＳＨＰＢ用于研究材料在高应变率下动态力学性能已为大家所熟悉，但用于研究结构的动态屈曲则未见报道，本文利用一装置对柱壳的动态塑性屈曲进行了实验研究，测出了壳体屈曲过程的载荷，轴向缩短量与时间的关系曲线，得到屈曲时的临介载荷与临介时间，同时发现壳体屈曲变形的一些规律并与静态实验的结果进行了比较，为理论分