CA6123SH2型城市客车设计

简要介绍CA6123SH2客车的设计思想、整车造型、结构设计、工艺和主要技术参数。     

强夯置换法加固软土路基的工程实践

在公路工程和市政道路工程中,在施工工期短的情况下,对软土路基的处理一直是工程中的难点问题。本文结合青岛市黄岛开发区滨海大道软土路基处理,采用强夯置换加固软土路基,取得了较好的效果,实践证明该方法具有技术简单可行,且经济合理的特点,能有效地加固软弱地基,减少软土层沉降和整体工程工后沉降,提高软土层的承载力等特点。     

预应力混凝土梁超载能力分析

为了验证利用有限元法分析预应力混凝土梁极限承载能力的准确性,对T形预应力混凝土模型梁进行了极限承载力加载破坏试验,采用ANSYS有限元程序,建立了T梁的分离式有限元模型,分析了模型梁从加载到破坏全过程的受力和变形。发现利用实验与有限元法得到T梁的荷载-挠度曲线与荷载-应变曲线的变化趋势一致,并呈现良好的非线性,但是通过荷载试验得到T梁的超载能力为9.07 kN.m,按照有限元分析得到的超载能力为12.48 kN.m,偏差较大,原因是分析模型偏于理想化。分析结果表明:利用有限元法在总体上能够有效地模拟钢筋混凝土梁受力全过程中各个量的非线性变化,对超载能力的求解是可行的。     

某发动机缸盖碗型塞密封失效分析及解决案例研究

碗型塞又名堵塞,因碗型塞的结构相对简单,可靠性高,价格便宜,广泛应用于内燃机.通过碗型塞与孔的过盈配合,及密封胶双重作用进行密封,碗型塞作为发动机常见的水道,油道密封方式,常见问题主要为漏液,因其结构简单,漏液问题根因也常常容易忽视;文章主要围绕发动机碗型塞漏水问题整改进行了理论分析和试验验证,为问题解决提供参考.     

特种弹药铁路运输可调式定位装置研究

概述了特种弹药铁路运输可调试定位装置的主要功能、技术要求、主要战技术指标，介绍了特种弹药铁路运输采用的从箱体顶部固定方式，并进行了相应的可调式定位装置研究，将装置分为整体固定和单点独立固定两种，用于固定弹箱在敞车内的位置，确保弹体运输安全。     

Effect of interference fits on the fatigue lives of bolted composite joints

The effect of interference fits on the fatigue lives of bolted composite joints is investigated by conducting mechanical tests. Static and fatigue tests are carried out on specimens made of carbon-bismaleimide composites joined together as double-lap single-bolt joints. The bolts having interference fits ranging of 0 (neat fit), 0.5%, 0.75% and 1% are performed. The results demonstrate the relationship between fatigue life and different values of interference fits. After the fatigue tests, non-destructive evaluation (NDE) and scanning electron microscope (SEM) are used to observe the damage of the surrender and surface of the hole. The test results show that the interference fitted specimens have improved fatigue life compared to the neat fitted specimen. The NDE and SEM results reveal that the damage degree of interference fitted specimen is weaker than that for the neat fitted one.     

Two degree of freedom flow-induced vibration of cylindrical structures in marine environments: frequency ratio effects

The flow-induced vibration of a cylindrical structure is a very common problem in marine environments such as undersea pipelines, offshore risers, and cables. In this study, the vortex-induced vibration (VIV) of an elastically mounted cylinder at a low Reynolds number is simulated by a transient coupled fluid–structure interaction numerical model. Considering VIV with low damping ratio, the response, hydrodynamic forces, and vortex shedding modes of the cylinder is systematically analyzed and summed up the universal rule under different frequency ratios. On the basis of the analysis, we find that the frequency ratio α is a very important parameter. It decides the locked-in, beat, and phase-switch phenomena of the cylinder, meanwhile, it also influence the vortex mode of the cylinder. The trajectory of the two degrees of freedom (2 DOF) case at different natural frequency ratios is discussed, with most trajectories having a “figure of 8” shape and a few having a “crescent” shape. A fast Fourier transformation technique is used to obtain the frequency characteristics of the vibration of the cylindrical structure. Using the 2 DOF cylinder model in place of the 1 DOF model presents several advantages in simulating the nonlinear characteristics of cylindrical structures, including the capacity to model the crosswise vibration generated by in-line vibration.     

城市道路沥青路面补强设计方案浅析

抚顺市城市道路建设近年来有了很大发展,但城市道路使用到一定年限后,如果使用性能降低,就要及时进行补强。以抚顺市城市道路沥青路面补强设计的现状为基础,探讨了合理的沥青路面补强设计方案。     

A new method for absolute datum transfer in seafloor control network measurement

To decrease the time consumption and the labor intensity in the absolute datum transfer of traditional seafloor control network measurement, a new method, namely sailing-circle positioning method, is put forward in this paper. First, the traditional intersection positioning model is improved by considering the equivalent sound velocity profile error as an unknown parameter in the adjustment model. Second, the effect of geometric dilution of precision (GDOP) on positioning accuracy is analyzed. By seeking for the minimum of GDOP, it is concluded that the absolute datum transfer can achieve the highest accuracy in the condition of sailing along a circle relative to other sailing paths. Moreover, the optimal radius of the circle for the accurate datum transfer is also given out. Besides, the correlation between the accuracy of datum transfer and the sound velocity error in this method is analyzed. Finally, the new method was tested and verified by the experiments in Songhua lake with the water depth of 60 m and in South China sea with the water depth of 2000 m, respectively. These experiment results show that the new method can improve the accuracy and efficiency of traditional datum transfer method significantly.     

对地铁运营物资高效管理的探讨

随着城市轨道交通的快速发展,轨道交通网络加剧成型,物资供应和保障面临巨大挑战,探讨新的物资管理模式势在必行。本文着重围绕供应链中的各个实施要点阐述,从价格比对体系、采购计划、供应商、库存管理和物资配送等方面进行了论述,对于从事轨道交通物资管理的相关人员有一定的参考和借鉴意义。