水泥土搅拌桩复合地基有限元分析

利用有限元法对水泥土搅拌桩复合地基的变形性状以及褥垫层厚度、持力层刚度、面积置换率对承载力影响规律进行了计算分析。并对水泥土搅拌桩复合地基的设计计算提出了一些看法。     

Research on Design Optimization Strategy in Virtual Product Development

Introduction WiththeadvanceofComputeraideddesign(CAD), Computeraidedengineering(CAE)andVirtualreality technology(VR),virtualproductdevelopment(VPD)is emergingasanewtechnologyusedbyleadingindustrytodevelopnewproductwithouttime consumingandexpensive physicalprototypetest.Virtualproduct,ordigitalmock up,isacomputersimulationofaphysicalproductthatcanbepresented,analyzed,andtestedfromconcernedproduct life cycleaspectssuchasdesign,manufacturing,service, andrecyclingasifonarealphysicalmodel.T…     

Mechanical, deformation and fracture behaviors of bulk metallic glass composites reinforced by spherical B2 particles

Ti_(45)Cu_(40)Ni_7Zr_5Sn_(2.5)Si_(0.5) alloys were prepared under various cooling rate conditions during solidification.The alloys exhibited different volume fractions of B2 particles with 0～40 vol%in an amorphous matrix.Monolithic bulk metallic glass of 1 mm diameter showed no macroscopic plasticity and exhibited the typical vein patterns in a maximum shear stress plane on the fracture surface.However,a bulk metallic glass composite containing the B2 particles revealed obvious plasticity(～5.6%)with a remarkable work-hardening behavior that resulted from a stress-induced martensitic transformation of the B2 particles.Moreover,the composite displayed the complicated fracture morphologies containing of three types of fracture features.Through detailed investigations on the microstructural evolution,mechanical,deformation and fracture characteristics,the influence of B2 particle on overall behavior of the TiCu-based bulk metallic glass composites was elucidated.     

关于Smarandache双阶乘函数与伪Smarandache函数的混合均值

对任意的正整数n,著名的Smarandache双阶乘函数Sdf(n)定义为最小的正整数m使得n|m!!,即Sdf(n)=min{m∶m∈N,n|m!!}。著名的伪Smarandache函数Z(n)定义为最小的正整数m使得nm(m+1)/2,即Z(n)=min{m∶m∈N,nm(m+1)/2}。利用初等方法和解析方法研究了复合函数Sdf(Z(n))的均值,并得到一个较强的渐近公式。     

Effect of La0.8Sr0.2Co0.2Fe0.8O3-δ morphology on the performance of composite cathodes

In the present work,one dimensional La0.8Sr0.2Co0.2Fe0.8O3 δ(LSCF) nanofibers with the mean diameter of about 100 nm prepared by electrospinning were deposited on Gd0.2Ce0.8O1.9(GDC) electrolyte followed by sintering to form one dimensional LSCF nanofiber cathode. And LSCF/GDC composite cathodes were formed by introducing GDC phases into LSCF nanofiber scaffold using infiltration method. The polarization resistances for the composite cathode with an optimal LSCF/GDC mass ratio of 1/0.56 are 0.27,0.14 and 0.07 Ω cm2at 650,700 and750 1C,respectively,which are obviously smaller than 2.26,0.78 and 0.29 Ω cm2of pure LSCF nanofiber cathode. And the activation energy is1.194 eV,which is much lower than that of pure LSCF nanofiber cathode(1.684 eV). These results demonstrate that the infiltration of GDC into LSCF nanofiber scaffold is an effective approach to achieve high performance cathode for solid oxide fuel cells(SOFCs). In addition,the performance of composite cathode in this work was also compared with that of our previous nanorod structured LSCF/GDC composite cathode.     

复合型研究生培养模式的理论思考与现实探索

当前我国硕士研究生教育中,主要存在学术型和应用型两种培养模式,前者侧重于培养研究生的理论深度与科研能力,后者侧重于培养研究生的技能提升与实践能力。两种培养模式并行不悖,各自具有自身的优势与局限。正在探索中的复合型研究生培养模式,本具有综合两种培养模式的优点,但在实践中仍然面临着考验。     

含氢聚硅氧烷/丙烯酸丁酯复合乳液的研究——影响乳液流变性及反应速率的因素

详细讨论了在一次加料法制备含氢聚硅氧烷（PHMS）／丙烯酸丁酯（BA）复合乳液中,单体、乳化剂、引发剂及反应温度对聚合反应速率、转化率和乳液流变性能的影响．结果表明：PHMS／BA复合乳液的表观活化能和聚合速率方程分别为：Ea＝132．77KJ／mol,（I为引发剂,E为乳化剂）该乳液呈假塑性流体特征,随PHMS、功能单体N-羟甲基丙烯酰胺（NMA）用量增加,乳液粘度增加;乳化剂用量增加,反应温度升高,粘度降低．选择适当的原料配比和反应条件,可在较高的反应速率下,制得转化率高、性能稳定PHMS／BA复合乳液．     

一类复合抛物型微分方程的Laplace空间解的相似结构

本文作者研究了一类复合抛物型微分方程在无穷大外边界条件和随时间变化的内边界条件下的初边值问题在Laplace空间的解的相似结构,它能很好地帮助我们认识模型遵从的内在规律及设计相应的应用软件．     

CFG桩复合地基不同参数沉降影响分析

结合兰永一级公路软弱路基处治技术研究项目,为分析不同设计参数下CFG桩复合地基处治软土路基的沉降变化规律,利用非线性有限元软件ADINA建立三维模型,结合比奥固结理论,地基土体按多孔介质材料考虑,采用Mohr-coulomb理想弹塑性模型做固结分析,将填土视为荷载逐级施加,采用生死单元对CFG桩复合地基进行数值模拟。结果表明,相比提高垫层模量与桩身模量,选择较大桩长与合理的桩距、桩径对减小软土路基沉降更为明显,裙桩效应对于减小软土路基沉降起积极作用,软土路基经过CFG桩复合地基处理后满足一级公路工后沉降要求,加固效果明显。     

复合材料加筋壁板长桁凸缘变厚度设计对长桁-蒙皮界面承载能力的影响

长桁与蒙皮之间的脱胶是复合材料加筋壁板主要的失效形式之一。本文首先对复合材料机翼结构长桁-蒙皮典型结构进行了三点弯曲试验,获得破坏载荷以及界面失效模式。然后基于ABAQUS建立三维有限元模型,采用内聚力模型模拟界面的破坏情况。有限元计算结果与试验结果吻合较好,验证了有限元模型的合理性。在此基础上,对长桁凸缘宽度方向采用渐变厚度设计,开展了其对长桁-蒙皮界面承载能力的影响分析。研究结果表明采用变厚度设计可以减缓长桁凸缘末端附近的刚度突变,降低长桁凸缘末端与蒙皮之间界面的面外载荷。凸缘变厚度设计可以有效避免长桁与蒙皮界面过早出现脱胶失效,长桁凸缘末端越薄,界面脱粘载荷越大。