SEISMIC ANALYSIS OF A SECONDARY STRUCTURE WITH MULTI-CONNECTIONS

应用结构动力学、随机振动理论对多点连接次结构系统的地震反应进行了分析 ,以次结构系统的功率谱密度函数在整个频率域内积分得到响应的均方根值 ,并考虑了调谐、干扰、非古典阻尼和空间干扰的影响。算例表明该方法具有很高的精度。In this paper, the structural dynamics and the theory of random vibration are used to analyze the response of a secondary structure with multi-connections. The mean-squre of response are calculated by integrating the power spectral density function of the secondary structure. The effect of tunning, interaction, non-classical damping and spatial coupling are also considered. Numerical example show the high accuracy of the approach proposed in this paper

桩基动力参数的灵敏度分析

将桩基简化成离散的多自由度系统,对其纵向振动的动力参数进行了分析,对桩基的振动参数频率、振型、频响函数与频域响应对刚度改变的灵敏度进行了数学推导.可知频率对刚度改变的灵敏度很小,振型对刚度改变的灵敏度也不大,但在节点处有一定的影响,频响函数与频域响应对刚度的变化反应比较明显,并且用一个实例进行了验算,得到的结果与理论推导吻合良好

有控互连结构体系的楼层反应谱分析

应用等效最优控制方法对互连结构体系被动控制器的刚度参数和阻尼参数同时进行了优化,并在此基础上,建立了安装有次结构时有控互连结构体系的动力学模型,研究了控制器参数优化设计结果对次结构楼层反应谱的影响,得出一些有参考价值的结论

三维实体结构的双向TMD优化设计

采用在结构顶层设置双向TMD被动控制的方法,对结构在多向地震作用下的振动进行了被动控制的研究.在建立三维结构控制体系的动力学模型后推导出结构-TMD联合动力方程,并以功率谱密度函数矩阵迹的积分为目标函数,利用单纯形法对双向TMD的参数进行优化设计.数值结果表明,利用双向TMD系统对结构进行被动控制的方法是可行且有效的,能对结构的平动和扭转起到较好的减震效果

Effect of ZnO on Cu/ZnO/Al_2O_3 catalysts for methanol synthesis

[中文文摘]用高速碰撞共沉淀法制备m(CuO) /m(ZnO) /m(Al2 O3 )比分别为 60 /3 0 /1 0和 3 0 /60 /1 0的 1 #和 2 #催化剂 ,结果表明高ZnO的 2 #催化剂活性较好 ,分散度较大。XPS测试表明 2 #催化剂表面ZnO吸附的中间体 (CHx 或CHxO)较多且表面的Cu+1浓度较高 ,从而促进CO加氢合成甲醇的活性。[英文文摘]Cu/ZnO/Al_2O_3 catalysts with ratios of 60/30/10 and 30/60/10 have been prepared by high speed collision coprecipitation method. The performance of the catalyst with the higher ZnO content shows the higher activity in methanol synthesis. The characterization results indicated that the catalyst with the higher ZnO content has higher dispersion. On the surface of the higher ZnO content catalyst, there was more Cu+1 and more intermediate (CH_x and CH_xO) adsorpted. It is beneficial for the CO hydrogenating to produce methanol

THE ANALYSIS OF FLOOR RESPONSE SPECTRUM IN EQUIPMENT-STRUCTURE INTERACTION FORM IN FREQUENCY DOMAIN

直接从由建筑物和设备组成的主次结构耦合系统各自的动力特性出发,考虑主次结构间调谐、干扰、非经典阻尼等因素的影响,推导出频率传递函数和次结构的加速度均方根响应,并由此进一步得到楼层的加速度均方根反应谱。这一方法避免了求解联合系统的复特征值和动力方程出现病态等问题,大大简化了计算过程。最后在算例中就次结构的阻尼比、质量比、安装楼层及场地土等因素对楼层加速度均方根反应谱的影响进行了讨论,算例表明,质量比是决定能否采用古典谱的关键因素,场地土对反应谱的影响也不容忽视。Based on the dynamic properties of the primary-secondary coupling structural system composed of an equipment and a structure,the frequency transfer function and the root mean square of acceleration response of the equipment are deduced directly,and the factors including tuning,interaction and non-classical damping have been taken into consideration in the process of deduction.Furthermore,the floor response spectrum of the root mean square of acceleration is obtained.Since the calculation of the complex eigenvalue problem and the ill-conditioned equation of motion of the combined system are avoided in this approach,the procedure of calculation is simplified greatly.In the end,the influencing factors on the floor response spectrum are discussed,including damping ratio,mass ratio,the location of the equipment and the soil of the building site.As shown in the numerical example,the mass ratio is the key factor in deciding whether the classical floor response spectrum may be used or not,and the influence of the soil of the building site should not be ignored

AN INVERSE METHOD OF PILE FAULTS′ IDENTIFICATION VIA FITTING STRESS WAVE CURVES

通过建立桩 -土系统的力学模型 ,给出了考虑桩土相互作用的应力波动方程的特征线解法 ,继而应用优化方法对桩身缺陷进行定量识别 ,在识别中利用完整桩的土参数反演以及对缺陷桩进行等效波阻抗反演和缺陷认定。数值模拟和工程桩实例表明 ,本方法对缺陷桩不仅能够较好地识别出来 ,而且对一次缺陷或二次缺陷的判断具有较高的反演精度。A mathematic model for pile-soil system is established. The method of characteristic lines to solve the stress wave equations is proposed considering the interactions of pile and soil.The optimization method can be used to quantitatively detect the faults in piles, where the soil parameters inversed from a model with complete pile are used to inverse the equivalent stress wave impedance for others with damaged piles and then identify their corresponding faults. Numerical examples of the simulation for experimental piles and of the detection for engineering piles show that the method gives the quite accurate results, especially for those with primary or secondary faults

某工程桩基质量问题的一种处理方法

据统计,国内灌注桩施工中桩身出现质量缺陷的概率达20%。一旦发生桩基质量事故,应及时进行事故原因分析评判,对事故进行处理,以保证建筑物的正常使用,并尽量减少经济损失。通过对一起桩基事故的分析和处理,说明其处理的方法及其原理,为今后相关处理提供经验借鉴

Experimental Study on RC Rectangular Columns Seismic Strengthened with Rectangular or Cylindrical Section

设计并制作了五组经过加固或未经加固的试件,在轴向压应力为5·6MPa的情况下,进行了水平反复加载试验。试验结果表明,RC矩形柱用外包钢或碳纤维以矩形或圆形截面形式加固后,变形性能得到明显的改善;由于轴压比不大,极限承载力提高不太明显;圆形截面的承载力加固效果好于矩形截面的;外包钢加固试件的耗能能力比碳纤维加固的稍大。In order to investigate the seismic behavior of RC rectangular columns strengthening with circular or rectangular steel plate and carbon fiber sheet jackets, five strengthened and non-strengthened column specimens are designed and constructed. Specimens are tested under constant axial compression stress of 5.6MPa, and alternately repeated lateral forces. The main conclusion is that the ultimate flexural strength and deformation capacity of the RC rectangular columns, which are confined laterally by the circular steel plate and CF sheet-jacket, are quite improved

基桩低应变动测的数值模拟及其在质量诊断中的应用

采用三维动力有限元方法进行各种缺陷基桩低应变动测的数值模拟,包括不考虑桩周土的模型桩和考虑桩周土的工程桩,分析中桩周土阻尼主要由局部单元的结构阻尼系数来实现.并且采用所模拟的基桩动测结果形成丰富和可靠的参考样本,进行基桩完整性的神经网络诊断.数值算例中,首先模拟了简单完整桩以及典型模型桩和工程桩,然后完成了各种缺陷类型的150余根模型桩和工程桩的数值模拟,并以此作为参考样本对模型桩和工程桩的完整性进行预测和诊断,结果验证了诊断方法的有效性