大直径PHC桩竖向承载力分布的试验研究

结合某跨海大桥桩基试验项目,对4组大直径PHC桩进行了竖向承载力静载试验,并通过桩身预埋的应变式钢筋计测试桩身轴力分布.试验结果表明,随着桩端土层刚度的提高,单桩极限承载力也将进一步增大,因此对于大直径PHC桩,也应选择较好土层作为持力层;随着桩顶荷载的不断增大,桩端阻力分担荷载所占的比例也逐渐增大,表明大直径PHC桩呈端承摩擦桩的承载性状;对于桩端持力层较好,而上覆软弱土层较厚的大直径PHC桩,尚应考虑上部土层侧摩阻力软化现象的影响;尽管大直径PHC桩桩身刚度较大,但在设计工作荷载下,此次试验的桩顶实测沉降主要由桩身压缩引起.     

装配式简支空心板梁纵向裂缝分析

根据我国公路桥涵设计规范规定的温差分布和实际情况假定的温度场,利用ANSYS软件对简支空心板梁桥进行温差应力计算分析,计算结果表明温度应力在整个桥梁设计中占有很大的比重,且横向温差应力是腹板产生纵向裂缝的主要原因.     

公路项目对旅游业效益贡献评价

根据公路项目与旅游业发展特性,建立公路项目对旅游业效益贡献的评价指标体系,其可作为公路项目对旅游业效益贡献的评价依据。     

Optimal interpolation of sea surface temperature for the North Sea and Baltic Sea

Sea surface temperature fields of the North Sea and Baltic Sea have been constructed for the year 2001 using a multiplatform Optimal Interpolation scheme. The analyzed fields are constructed every 12 h on a 10 km spatial grid. The product is based upon observations from the three NOAA satellites 12, 14 and 16 together with a large amount of in situ observations. Space dependent covariance functions are estimated from the satellite observations and account for spatial and temporal lags. Several independent methods have been used to assess the error on the sea surface temperature product. Compared against independent in situ observations, the mean RMS difference for the year 2001 is 0.78 °C. The spatial distribution of the errors reveals that the Baltic Sea in general show higher errors than the North Sea. The error statistics throughout the year show a temporal variation of the errors with maximum during summer and winter. Tests with a varying number of satellite observations show that the accuracy of the satellite observations is the most important parameter in terms of reducing the errors on the interpolated sea surface temperature product.     

舰船设备抗冲击性能校核评估系统概念设计

通过对舰船设备冲击试验现状以及计算机建模仿真水平的研究分析,论证了开发舰船设备抗冲击性能校核评估系统的必要性和可行性.根据舰船设备抗冲击仿真计算的要求和特点,提出了舰船设备抗冲击性能校核评估系统应当具备的基本功能和总体构架,并分别对系统各模块的功能特性和相互关系进行了较为细致的研究分析.在系统的设计过程中采取了一系列优化的措施,以最大限度地提高系统的运行效率和可靠性,为下一步开发舰船设备抗冲击性能校核评估系统奠定了基础.     

CNG/汽油双燃料汽车燃气ECU的设计

介绍所设计的双燃料汽车燃气电控模块的组成、原理及设计过程,将该电控模块与原车的ECU和氧传感器一起构成闭环控制系统,可实现对燃气喷气量的精确控制。通过利用原车ECU的控制策略,可缩短开发周期,节约开发成本。通过试验验证了所设计的燃气ECU的控制性能。     

电喷汽油机燃用甲醇-汽油混合燃料的排放及催化转化特性研究

研究了多点电喷汽油机燃用不同掺混比的甲醇汽油混合燃料时的排放及催化器的转化性能。研究结果表明:在汽油机参数未做任何调整的情况下,甲醇对催化器前的CO、HC和NOx排放及其催化转化效率的影响与汽油机的转速、负荷和空燃比控制策略有关;随着甲醇汽油混合燃料中甲醇含量的增加,未燃甲醇的排放量变化不大,甲醛排放量增大,乙醇的排放量略有降低,乙醛的排放量很低并基本保持不变;醇、醛类排放经过三效催化转化器后基本接近零排放水平。     

天津港防波堤延伸工程口门方案研究

根据发展的需要,天津港拟在原25万t航道北侧增加一条10万t级航道。由于航道宽度增加,设计口门宽度由900 m增加到1550 m,在现场实测资料分析的基础上,利用潮流、泥沙数学模型对口门拓宽后口门附近流场以及航道淤积情况进行了研究,建立波浪数学模型,对南疆码头附近泊稳以及波峰面高程进行了研究,主要结论是与原900 m时相比,口门拓宽后口门附近流态基本没有发生变化,航道淤强略有增加,但幅度不大,而口门拓宽后30万t油码头处波高有所增大,不能满足设计要求,将北防波堤向海延伸500 m后,30万t油码头处波高可以满足设计要求。     

C-NCAP评价结果统计分析

C-NCAP自2006年8月实施后,到2008年底已经发布了65种车型的评价结果,对汽车安全技术的发展起到良好的导向作用.文中对这65种车型的评价结果进行了统计分析,揭示了一些与试验相关的特点.     

Controller design for soft-disability remedy of the electric power steering system

The electric power steering (EPS) system is designed to reduce the effort exerted by driver on the steering wheel. One of the most common and critical failures of EPS is the soft-disability of the torque sensor or the loss of its signal, which leads to the instant shutdown of the EPS system while turning and causes serious traffic accidents. In this paper, a novel controller based on the self-alignment torque (SAT) estimation was designed to remedy the soft-disability of EPS system. After the SAT estimation method was verified by the empirical Magic Formula (MF) tire model, the remedy control strategy based on the SAT estimation was developed and evaluated by simulations under step and sinusoidal inputs. To further evaluate the performance of the controller on a real vehicle, experiments on a real EPS system were implemented under step and sinusoidal inputs. The results of simulation and experiment using the controller based on estimated SAT showed this controller to be feasible and capable of eliminating the abrupt reaction torque increment caused by shutdown of EPS and of remedying the soft-disability of EPS system under common input signals.