沥青路面破损程度分级与破损换算系数取值的探讨

本文分析现行规范中对沥青路面破损程度、密度分级以及破损换算系数取值中存在问题,通过分析沥青路面破损程度与路面使用状况关系,结合沥青路面养护措施,提出沥青路面裂缝破损密度分级的方法,并对车辙破损严重程度分级标准、裂缝和车辙破损换算系数的修正值提出建议。     

多孔材料垂直渗透系数测定装置的研究

在对渗透系数影响因素的分析研究基础上,针对原有渗透仪在侧漏、低水头下测量困难等缺点,就测压管位置、测压管直径、测量用水及试件尺寸方面规范化多孔渗透系数测定仪。为减少试件表面附着的气泡,采用抽真空后,而不采用分层浸泡的方法。最后就渗透测定仪装置提出几条改进建议:用充气气囊代替柔性侧壁,用差压计代替微压计。实践证明本仪器使用稳定,数据重复性高。     

沥青混凝土转运车对提高道路施工质量的试验研究

对道路摊铺过程中采用摊铺机直接摊铺作业和采用徐工AT1000A型转运车与摊铺机联合施工作业的试验路面效果进行了对比,分析了摊铺温度场和骨料摊铺效果.结果证明使用沥青混凝土转运车是提高道路施工质量的有效手段.     

挂篮底模纵梁受力简化计算方法及承重分配系数

以一桥梁施工工程实例为依托,采用有限元软件ANSYS对桥梁悬臂施工中使用的菱形挂篮进行仿真分析.提出3种简化模式计算底模纵梁的承重分配,对比发现将底模纵梁承受的外荷载简化为集中荷载,并分配至挂篮下前后横梁的方法是最优简化计算方法.在此基础上对挂篮底模纵梁承重分配系数进行优化,从而简化了繁琐的挂篮底模纵梁受力分析计算,保证了挂篮结构设计和施工的安全.     

Tuning of transfer functions for analysis of wave–ship interactions

Transfer functions are often used together with a wave spectrum for analysis of wave–ship interactions, where one application addresses the prediction of wave-induced motions or other types of global responses. This paper presents a simple and practical method which can be used to tune the transfer function of such responses to facilitate improved prediction capability. The input to the method consists of a measured response, i.e. time series sequences from a given sensor, the 2D wave spectrum characterising the seaway in which the measurements are taken, and an initial estimate of the transfer function for the response in study. The paper presents results obtained using data from an in-service container ship. The 2D wave spectra are taken from the ERA5 database, while the transfer function is computed by a simple closed-form expression. The paper shows that the application of the tuned transfer function leads to predictions which are significantly improved compared to using the transfer function without tuning.     

车辆隔热壁K值计算中空气层的处理方法

对轨道交通车辆多层复合结构的隔热壁进行隔热性能理论计算与仿真计算的对比,对隔热壁内部空气层的隔热性能进行分析。结论为:在车辆多层复合结构的隔热壁K值计算中,当空气层厚度大于一定厚度时,流体自然对流对隔热壁的隔热性能影响较大。利用多项式密度(Polynomial Denisity)和Boussinesq模型两种算法,对所得结论进行了验证。     

The symbolism of ‘eco cars’ across national cultures: Potential implications for policy formulation and transfer

Transport choices are not merely practical decisions but steeped in cultural and societal perceptions. Understanding these latent drivers of behaviour will allow countries to develop and import policies to more successfully promote sustainable transport. Transport symbolism – what people believe their ownership or use of a mode connotes to others about their societal position – has been shown to be one such, non-trivial, hidden motivator. In the case of hybrid and electric cars (‘eco cars’), studies have demonstrated how their symbolic value varies within a society among different social groups. As yet, however, there has been scant research into comparing how the symbolism of a mode varies across national cultures, horizontally, between individuals with similar socio-demographic characteristics. Through qualitative thematic analysis, this study utilises two of Hofstede’s cross-cultural indices – power differential and individualism versus collectivism – to develop and strengthen theory on how the differing symbolism of eco cars currently varies between four cultural clusters – Anglo, Nordic, Confucian and South Asian. It also deliberates how observed symbolic qualitative differences may influence an individual or group choice to procure eco cars. Finally, it discusses how policy development, transfer and marketing, within the context of eco cars, may need to be modified by national governments, in the Confucian and South Asian cultures, so as to encourage uptake and modal shift.     

舰船加筋板局部强度评估中的总纵应力折减系数研究

舰船加强筋尺寸的合理确定一直是结构设计中的热点问题。本文综合考虑总纵弯曲应力和局部载荷的相互作用,研究加强筋的许用应力折减系数(C_s)的影响因素与合理取值方法。通过分析加强筋的力学模型、对比不同规范中的C_s取值,以及用非线性有限元软件Abaqus计算一系列加筋板模型,拟合C_s曲线并与规范对比,并验证剖面对称性和局部载荷作用方向对C_s取值的影响方式,丰富了舰船局部强度校核方法的技术背景,为板架设计、舰船三维局部校核程序开发提供借鉴。     

船用厨房和具有烹调设备的配餐室的通风计算及空气处理方法

本文介绍了ISO 9943-2009国际标准和GBT 20846-2007中国国家标准中对船用厨房和具有烹调设备的配餐室的通风计算及空气处理中提出的送风量的计算方法，提出另一种更易于大家理解和接受的简易计算方法和空气处理过程，供工程技术及设计研究人员参考。     

Modeling free-flow speed according to different water depths—From the viewpoint of dynamic hydraulic pressure

In this paper, we propose a method of modeling free flow speed from the viewpoint of hydroplaning. First, the lift forces for different water depths were estimated using Bernoulli’s equation. Compared with the result of the experimental test performed by the Japan Automobile Research Institute, the hydrodynamic pressure coefficient was determined to be 0.03 (tf s²/m⁴). The validation of the predicted lift force is found in another published paper. A very good match is found between the computed values by the proposed numerical model and the data in other published papers. Then, the loss of contact force is considered to evaluate the hydroplaning performance of a tire. To simulate the hydroplaning speed, a tire-sliding model was utilized to obtain the traction and friction forces between the road surface and the tire. The observation data obtained in Japan in 2009 is compared with the physically computed hydroplaning speed, yielding the conclusion that the traction force at the measured desired speed is, on average, 23.4% of the traction force at hydroplaning speed. The analytical model offers a useful tool to quantitatively show that the free flow speed changes as the water depth increase.