半无限弹性体地基上水平荷载桩的静力分析

本文利用弹性理论 ,建立半无限弹性体地基上水平荷载桩的力学模型 ,推导出其静力分析的基本方程 ,给出水平荷载桩静力分析的弹性理论求解方法 ,并通过实例加以说明。     

Similarity on fire behavior of reinforced concrete beams with pre-damage

为研究不同比例钢筋混凝土预损伤梁火灾行为的相似性，在已有缩尺模型明火试验的相似理论基础上，对不同几何尺寸比例的3根钢筋混凝土无损梁和9根因经历常温静载试验而产生不同程度预损伤的梁开展明火试验。试验结果表明：采用热辐射模型确定不同比例梁明火试验的升温曲线，可以较好地实现不同比例梁在相应时间点截面温度分布相似；明火试验前形成的宽度在2 mm以下的裂缝对不同比例梁温度场的相似性影响不大，仅影响局部混凝土温度，明火试验前梁上已有的残余变形对其耐火极限影响不大；将不同比例梁受火时间的相似比由几何比例的平方调整为几何比例的1.8次方，可以实现预损伤程度相同的不同比例钢筋混凝土梁挠度变化以及耐火极限相似，从而实现由缩尺模型梁的火灾下力学行为预测足尺原型梁的火灾力学行为。     

高桩承台桩基拱桥整体结构与土相互作用分析

针对在桥梁工程中广泛使用的高桩承台桩基础，介绍了拱桥整体结构与土相互作用的有限元模型的计算方法，结合实例，将此法与传统计算法作了对比，并得出结论。     

A novel application of TPAD-MBR system to the pilot treatment of chemical synthesis-based pharmaceutical wastewater

A pilot-scale test was conducted with a two-phase anaerobic digestion (TPAD) system and a subsequential membrane bioreactor (MBR) treating chemical synthesis-based pharmaceutical wastewater. The TPAD system comprised a continuous stirred tank reactor (CSTR) and an upflow anaerobic sludge blanket-anaerobic filter (UASBAF), working as the acidogenic and methanogenic phases, respectively. The wastewater was high in COD, varying daily between 5789 and 58,792 mg L(-1), with a wide range of pH from 4.3 to 7.2. The wastewater was pumped at a fixed flow rate of 1m(3)h(-1) through the CSTR, the UASBAF and the MBR in series, resulting in respective HRTs of 12, 55 and 5h. Almost all the COD was removed by the TPAD-MBR system, leaving a COD of around 40 mg L(-1) in the MBR effluent. The pH of the MBR effluent was found in a narrow range of 6.8-7.6, indicating that the MBR effluent can be directly discharged into natural waters. A model, built on the back propagation neural network (BPNN) theory and linear regression techniques, was developed for the simulation of TPAD-MBR system performance in the biodegradation of chemical synthesis-based pharmaceutical wastewater. The model well fitted the laboratory data, and was able to simulate the removal of COD.     

基于 STAR-CCM＋对5415船模的阻力预报

以5415船模为研究对象,介绍了 STAR －CCM＋对5415船模的数值仿真过程,对该船模的阻力、升沉及横倾角进行了数值计算,并与现有的试验值进行对比,验证了 STAR －CCM＋对该船型在静水运动中数值模拟的有效性;研究表明：总阻力系数、剩余阻力系数都是随 Fr 增大而增大,当 Fr ＜0．35时,增长缓慢,当 Fr ＞0．35时,增长迅速;同时在 Fr ＝0．35时,横倾角发生了显著的变化,Fr ＝0．35是该船模静水阻力性能发生变化的分界点。     

BCC金属物理型动态本构关系及在钽中的应用

构建了一种新的、基于塑性变形物理机制的BCC金属动态本构关系,然后将其应用于军用材料钽,通过采用新的约束条件下的多变量非线性规划方法,结合有关流应力实验数据确定出了多晶钽的本构模型。计算结果表明,该模型与实验数据吻合较好,而与Z-A本构模型相比其准确性得到提高,与NN-I本构模型相比预测能力接近,但实用性更强。另外,验证可知该模型的适用条件可以有效外推至很宽的温度及应变率范围。     

基于点质量模型的扰动引力快速计算

为解决扰动引力快速计算的时效性和精确性问题,在点质量模型基础上,根据扰动引力矢量随空间位置的变化规律,提出了三次样条函数对扰动引力空间变化规律进行数值逼近,分别对点质量模型的四个频段空间采样点扰动引力进行样条函数插值仿真,降低了计算复杂度,解决了由于数据计算引起的延时误差问题.结果表明:该方法实现了弹载计算机快速计算,并具有良好的计算精度.     

基于模糊综合评判的装备采购评标方法

针对装备协作配套件采购评标问题,提出将模糊综合评判引入到装备采购的评标中去,建立了基于模糊综合评判的评标模型.以某装备协作配套件采购招标为例,其评标步骤包括:建立评语集、建立权重集、确定各因素隶属函数及进行模糊评判,得出结论.     

演化硬件的应用与发展

演化硬件将可编程逻辑器件的结构位串当作染色体,通过演化算法进行搜索,找出符合要求的染色体,把它配置可编程逻辑器件,得到的即是要设计的硬件电路.其应用采用遗传算法,包括电路进化设计和在线自适应与容错两个主要方向.演化硬件则面临硬件平台的选择及演化硬件的可升级性两方面的挑战.     

A modified solution of radial subgrade modulus for a circular tunnel in elastic ground

In models based on Winkler springs for tunnel lining design, designers always face the difficulty of selecting appropriate values for the radial subgrade modulus (k_r). The widely used solution k_r for a circular tunnel in elastic ground proposed by Wood (1975) was found to be applicable only when the tunnel radial deformation is oval-shaped. On the basis of the Wood׳s solution, this note presents a general solution for k_r when the radial deformation of the tunnel is described by a Fourier series. This modified Wood׳s solution of k_r using compatible stress functions is validated by a numerical example. The modified solution for the example shows good consistency with the original Wood׳s solution when the tunnel becomes an oval shape with deformations. The example indicates that the magnitude of k_r is significantly affected by the distribution shape of the tunnel radial deformation. The value of k_r is no longer a constant value around the tunnel when the tunnel deforms into a general shape described by a Fourier series. It is quite different from the value of k_r for a distribution shape described by a single Fourier term, i.e. one involving a single frequency. The application of a general solution for k_r is illustrated by a design case using a bedded beam model.