柔性薄片和多孔材料声透射系数的声管测量

采用驻波管四传感器法可以测量小样品、薄型样品的垂直入射复透射系数.采用两类样品测试:一类是柔性高分子薄片,通过对薄片振动的有限元分析验证测试的正确性;一类是多孔吸声材料,发现它的隔声量并不遵从质量作用定律.最后给出了测试随机误差,证实此方法切实可行.     

Probabilistic fatigue crack growth analysis of spot‐welded joints

This paper presents a probabilistic fatigue crack growth life prediction methodology for spot‐welded joints under variable amplitude loading history. The loading is multi‐axial and is obtained from transient response analysis of a vehicle model using finite‐element analysis. A three‐dimensional (3D) finite element model of a simplified joint with four spot welds is developed, and the static stress analysis of this joint is performed. Then the fatigue crack inside the base material sheet is modelled as a surface crack. Probabilistic crack growth model is combined with the stress analysis result to develop a probabilistic fatigue crack growth life prediction methodology for spot welds. This new method is implemented with MSC/NASTRAN and MSC/FATIGUE and is useful for the reliability assessment of spot‐welded joints against fatigue crack growth.     

穿孔机导盘润滑技术研究

13Cr钢管在穿孔时的润滑技术和冷却技术与传统轧制工艺有所不同 ,对此问题进行研究 ,使其满足轧制 1 3Cr钢钢管的新工艺要求 ,最终达到轧制高质量 1 3Cr钢钢管的目的     

加强管理与改造降低氧化铝能耗

根据山东分公司近几年科技项目的投入,对烧结法生产氧化铝工艺能耗的降低所发挥的作用,主要有熟料窑、高效沉降槽、脱硅系统改造、氢氧化铝过滤改造、蒸发器及焙烧改造等。     

汽拖AV40-11轴流压缩机组在广钢420m3高炉上的应用

本文主要介绍了广钢汽拖AV40-11轴流压缩机组的结构和特点，控制系统概要、应用效果。     

Approximate analytic solutions of adiabatic capillary tube

Approximate analytic solution of capillary tube is valuable for theoretical analysis and engineering calculation. In this work, two kinds of approximate analytic solutions of adiabatic capillary tube have been developed. One is the explicit function of capillary tube length. Another is the explicit function of refrigerant mass flow rate. In these solutions, the choked flow condition is taken into account without iterative calculations. The approximate predictions are found to agree reasonably well with experimental data in open literatures.     

HTAC辐射管在燃气真空热处理炉中的应用

概要介绍了HTAC辐射管技术，并阐述了其结构和特点，以及蓄热式辐射管燃气真空炉结构和特性。     

关于随机变量函数的几个定理

在一般教科书中度献中对随机变量函数研究较少，本通过对随机变量函数研究．给出了有关随机变量函数的几个定理及证明。     

Numerical simulation of turbulent flow in helically coiled open-channels with compound cross-sections

Turbulence structure in a helically coiled open channel flow is numerically simulated using three different turbulence models-the Launder and Ying model, the Naot and Rodi model, and the nonlinear k-ε model (SY model). Simulation results were compared with observation of (i) turbulent flows in alternating point-bar type channel bends with rectangular sections, and (ii) straight open channel flows with compound cross-sections. Based on calculations of the impact of various channel curvatures on turbulence characteristics, accuracy of the three turbulence models was analyzed with observed data as a qualitative reference. It has been found out that the Launder and Ying model and the nonlinear k-εmodel are able to predict the same general trend as measured data, and the simulation of the effect of the centrifugal force on the formation of secondary currents produces a correct pattern.