弧形闸门支铰钢梁振动时效消应技术研究与实践

通过对刘家道口枢纽节制闸弧形闸门支铰钢梁采用了振动时效消应技术进行研究,其消应效果达到了有关规范和标准要求,满足了建设工期、质量、运行安全、环保、安全生产等。该研究成果的取得,为该工程带来了显著的经济效益和社会效益,同时为同类工程消除残余应力提供了范例和经验,对类似100 mm特厚钢板的箱形构件消除应力方面,具有重要的指导意义,也为100 mm以上特厚焊接钢构件振动时效的研究应用打下了基础。     

振动及加热壁面条件下的近壁空泡溃灭可视化研究

采用低压电火花生成空泡的方式系统研究了复杂壁面条件下的近壁空泡溃灭行为。通过不同类型振动壁面及不同温度壁面附近的空泡溃灭行为的可视化试验,发现壁面振动对空泡溃灭有促进作用,空泡溃缩过程更快,体积变化更显著。不同类型壁面对空泡溃灭过程的影响不同,柱形壁面相较于球形壁面,近壁的空泡形态较不规则,溃灭呈现整体塌陷的趋势,在反弹阶段会形成不规则的空泡云。壁面升温会使得近壁空泡产生明显趋向于壁面的溃灭行为,并伴随多次空化的现象,这会对壁面造成严重损伤。     

德瑞克高频细筛在峨口铁矿选厂扩能改造中的应用

介绍了美国德瑞克重叠式高频振动细筛在峨口铁矿选矿厂321系统扩能改造中的应用和效果。德瑞克细筛的高效、精确分级,提高了三段磨矿的磨矿分级效率,提高了321系统处理原矿的能力。     

常压下二乙二醇丁醚密度与温度的相关性

以空气和去离子水为标准样,利用Anton Paar DMA60 DMA602振动管密度计测定了常压下二乙二醇丁醚在20-60 ℃间几乎每相间1 ℃密度数据.其中系统温度的控制精度在0.01 ℃,密度的测量精度为0.000 1 g·cm-3.同时,利用不同的函数关系,将测量密度与对应温度的数据进行非线性最小二乘法拟合,给出了密度函数的对应参数.对比得出密度与温度间的最优线性函数关系,并且线性函数计算密度的标准误差为0.000 1 g·cm-3,符合密度测量精度要求.     

蒸发波导水平不均匀性对电磁波传播的影响

蒸发波导是海上一种典型的异常大气折射结构,它能够部分陷获电磁波从而改变电磁波的传播特性.目前对电磁波在波导环境下传播特性的研究多数假定波导是水平均匀的,却很少考虑波导的水平不均匀情况.利用电磁波传播的抛物方程(PE)模型,通过仿真研究了波导水平不均匀性对其传播特性的影响,定量分析了不同收发高度及不同频率条件下电磁波路径损失的变化规律.结果表明,波导不均匀条件下电磁波传播的路径损失与均匀条件下明显不同.     

特种多轨道炮发射振动分析

利用ANSYS有限元软件建立多轨道炮发射模型,计算得到了其发射瞬间的振动响应曲线.依据振动响应计算结果,可知连续发射弹丸时各轨道间振动对强度的影响满足系统可靠性要求,这些为结构的进一步改进提供了理论依据.     

微冲裁模具的微细电火花加工工艺研究

为了实现微冲裁加工,采用微细电火花加工技术在线制备了复杂形状的高精度微冲裁模具。采用超声波振动加工液的方式,促进加工屑从放电间隙中排出,从而使加工效率和加工精度得到明显提高,实验结果证明了该方法的有效性。最后,对所加工的微冲裁模具的尺寸误差进行了讨论与分析。     

系杆拱桥吊杆索力测试研究

系杆拱桥的吊杆比较短,吊杆索力受两端约束条件影响比较大,采用振动频率法分析了吊杆在两端铰接、两端固结和等效铰接等3种约束条件下,其实测索力与设计值之间的差异.测试结果表明,将吊杆两端简化为等效铰接,综合考虑了吊杆抗弯刚度和两端约束条件的影响,根据吊杆振动频率与索力之间的关系,计算吊杆索力精度比较高,满足工程要求.     

弹塑性防落梁球型钢支座试验研究

结合弹塑性防落梁支座设计原理,进行了弹塑性防落梁支座体系振动台试验,试验结果表明：弹塑性防落梁支座在减少地震能向上部结构传递的效果明显,从而验证了该支座设计原理的可行性。     

Experimental research on compaction characteristics of aeolian sand

Unlike other road materials, aeolian sand has some compaction characteristics that are key factors in construction qualities of highway in the desert. In order to study the characteristics, a series of laboratory and field tests were performed, including sieve analysis, standard modified compaction, vibrating compaction and field test. By analyzing the sieve analysis test data, it was found that the gradation of aeolian sand was bad, with fine grains whose diameters mostly ranged from 0.25 mm to 0.074 mm. Then, from the laboratory compaction test results, a compaction curve similar to the horizontallywritten letter S was obtained. That was quite different from the other kinds of road materials. There were two peak values in the curve with the increase of water content, which was the special characteristic of aeolian sand: to be well compacted whether it was dry or wet. Also, according to laboratory vibrating test results, the best vibrating frequency range was proposed. It was from 45 Hz to 50 Hz. Moreover, some field compaction tests were carried out. On the construction site of the highway, the aeolian sand subgrade was compacted in the condition of natural water content with optimizing construction machines. Its compaction degree reached 96%, meeting the current specifications. At last, comparative studies were carried through with electron microscope. It was shown that the microstructure of compacted dry aeolian sand is much denser than that of the natural one in the field test. __________ Translated from Chinese Journal of Geotechnical Engineering, 2007, 29(3): 360–365 [译自: 岩土工程学报]