二维正方形结构的液体声子晶体的声波带隙

用改进平面波方法研究了正方形点阵排列的水—汞体系中正方框柱对带隙的影响。

南京某工程地下室柱网及顶板结构布置方案研究

安全、适用、经济是设计的原则,其中经济性已经越来越受到建设者和设计者的重视。文章以南京河西某项目的地下室柱网及顶板结构布置方案分析比较过程为例,展示了方案优选的过程及重要性。

Numerical simulation of flow around square cylinder using different low-Reynolds number turbulence models

ABE-KONDOH-NAGANO,ABID,YANG-SHIH and LAUNDER-SHARMA low-Reynolds number turbulence models were applied to simulating unsteady turbulence flow around a square cylinder in different phases flow field and time-averaged unsteady flow field.Meanwhile,drag and lift coefficients of the four different low-Reynolds number turbulence models were analyzed.The simulated results of YANG-SHIH model are close to the large eddy simulation results and experimental results,and they are significantly better than those of ABE-KONDOH-NAGANO,ABID and LAUNDER-SHARMR models.The modification of the generation of turbulence kinetic energy is the key factor to a successful simulation for YANG-SHIH model,while the correction of the turbulence near the wall has minor influence on the simulation results.For ABE-KONDOH-NAGANO,ABID and LAUNDER-SHARMA models satisfactory simulation results cannot be obtained due to lack of the modification of the generation of turbulence kinetic energy.With the joint force of wall function and the turbulence models with the adoption of corrected swirl stream,flow around a square cylinder can be fully simulated with less grids by the near-wall.

不同应变速率下CFRP约束混凝土方柱的力学性能

为研究不同应变速率下碳纤维增强树脂复合材料(CFRP)约束混凝土方柱的力学性能,本文采用CFRP约束倒角半径为15 mm、45 mm、60 mm的方形试件,进行应变速率为3.3×10^(-5)s^(-1)、3.3×10^(-3)s^(-1)的加载试验,分析了试件倒角半径和应变速率对CFRP约束混凝土方柱的应力-应变曲线、轴向应变-环向应变曲线和抗压强度的影响。结果表明,试件的应力-应变曲线的第二段斜率和抗压强度均随着试件倒角半径与应变速率的增加而增大;轴向应变-环向应变曲线的斜率随着应变速率的增加而增大,随着CFRP的层数增大而减小。最后基于试验数据对现有文献的模型进行评估,结果表明Lin等模型的预测结果与准静态下FRP约束混凝土方柱的轴向应变-环向应变关系曲线比较吻合,魏洋等模型能够预测FRP强弱约束状态,Cao等模型可以用于预测不同应变率下CFRP约束混凝土方柱的抗压强度。研究成果为CFRP约束混凝土方柱的进一步应用提供了试验依据与理论基础。