不同交联度环氧沥青混合料低温弯曲性能研究

采用交联度分别为75.3%,71.4%,67.3%和58.4%的环氧沥青混合料进行-20℃,-10℃,0℃,10℃温度下小梁三点弯曲性能试验,构建了混合料弯曲强度、弯曲模量、弯曲破坏应变及弯曲应变能密度与温度、交联度的关系方程。结果表明：不同交联度的环氧沥青混合料弯曲强度与模量随着温度的提高而降低,弯曲破坏应变与弯曲应变能密度随着温度的提高而增大;不同交联度的环氧沥青混合料弯曲强度、弯曲模量、弯曲破坏应变及弯曲应变能密度与温度关系基本一致,各弯曲性能参数的温度敏感区间基本相同;温度敏感区间弯曲性能参数变化幅度较大,低于温度敏感区间,则弯曲性能参数变化幅度较小;环氧沥青混合料低温弯曲性能参数与温度、交联度之间具有较好相关性,提出的回归方程可以用于混合料低温弯曲性能预测。     

长途客车制动性能模拟计算分析

针对长途客车行驶过程中频繁出现的由于制动性能而导致的安全隐患,为了进一步完善和提高车辆制动性能参数的设计效率,建立了长途客车整车动力学计算模型,制动系统动力学模型以及轮胎模型,并在Visual C++环境下编写了长途客车制动性能模拟计算系统,通过模拟计算分析获得长途客车制动过程中的制动性能参数及响应曲线,并判断其是否符合相关制动性标准,为制动性能的完善提供了可靠、有效的参考。     

Simulation of active steering control for curving under traction in hauling locomotives

Active steering control in the form of secondary yaw control (SYC) and actuated wheelset yaw (AWY) have been in prototype development. This paper presents a new active steering bogie design, actuated yaw force steering (AY-FS), that is able to steer under high traction loads in tight curves. The AY-FS bogie design is compared with the AWY design. The steering performance AWY under high traction loads has not been previously reported. This paper examines five control methods, three for AWY and two for AY-FS bogies and assesses the traction curving and stability control performance of the alternative designs and control methods compared with each other and to passive steering bogie designs. The curving performance results showed considerable advantage in the proposed AY-FS bogies over the AWY. It was shown that control must be applied to both the yaw angle and the steering angle of the bogie to achieve the best traction steering performance which was not possible with the AWY bogies. The proposed new bogie designs of AY-FS overall give better traction curving and stability performance than the AWY designs.     

A yaw-moment control method based on a vehicle's lateral jerk information

Previously, a new control concept called ‘G-vectoring control (GVC)’ to improve vehicle agility and stability was developed. GVC is an automatic longitudinal acceleration control method that responds to vehicle lateral jerk caused by the driver's steering manoeuvres. In this paper, a new yaw-moment control method, which generates a stabilising moment during the GVC command and has positive acceleration value and the driver's accelerator pedal input is zero, was proposed. A new hybrid control, which comprises GVC, electric stability control and this new control, was constructed, and it was installed in a test vehicle and tested on a snowy surface. The very high potential for improvement in both agility and stability was confirmed.     

基于现场钻芯取样的沥青结构层抗车辙性能评价方法

为了快速检测与评价所铺筑沥青路面结构的抗车辙性能,提高沥青路面施工质量水平,首先设计了圆柱形试件车辙试验所需的试验模具,采用ANSYS软件模拟圆柱形试件和板式试件的车辙试验,分析了圆柱形芯样车辙试验的可行性;其次采用2种基质沥青、1种改性沥青、5种级配的5组沥青混合料,在不同厚度和温度条件下进行圆柱形芯样车辙试验,分析确定了圆柱形芯样车辙试验的条件;最后结合现行规范要求,根据板式试件车辙试验和圆柱形试件车辙试验的相关性,建立了基于现场钻芯取样的沥青路面抗车辙性能检测标准。研究结果表明:可采用70℃下路面圆柱形芯样的车辙试验评价沥青路面高温抗车辙能力,并要求高温性能质量标准下的车辙动稳定度大于2 450次.mm-1;该法可实现对现场沥青路面抗车辙性能的快速检测与评价,有利于提高混合料设计水平与路面施工质量。     

土-结构相互作用的桥梁多尺度建模与分析

考虑土-结构相互作用(SSI)是地震激励下桥梁抗震性能评估的热难点之一.由于考虑土体影响多而建立的结构模型计算耗时极长,为了提高效率,现采用一致多尺度建模方法,将所研究部位建为实体单元,其他部位建为梁单元,单元之间采用适当的方法进行界面连接,保证宏观、精细单元间的变形协调,并对某一桥梁进行分析,验证了该方法的正确性.在...     

高黏改性剂与基质沥青配伍性研究

为了在有限样本条件下得到高黏改性剂优选基质沥青的控制指标,对境内外2种高黏改性剂与4种常用基质沥青进行配伍性试验,并以针入度、软化点、低温延度、60℃动力黏度及170℃布氏黏度为控制指标,从而得出配伍性最佳的基质沥青,然后分别对每种基质沥青进行针入度、软化点、延度等全套常规性能试验和不同老化程度的温度扫描、频率扫描等流...     

木质素纤维对再生透水沥青混合料路用性能研究

通过向透水沥青混合料(OGFC)中引入废弃混合料(再生OGFC)制备出再生OGFC,研究了木质素纤维掺量(0.01％、0.02％和0.03％)对再生透水沥青混合料路用性能(水稳性、高温性能、低温抗裂性能、抗滑性能和内聚强度)的影响.结果表明,引入再生OGFC料对混合料水稳性和低温抗裂性有明显不利影响,且对抗滑性能影响不...     

不同温拌剂对沥青路用性能的影响

为研究不同类型温拌剂对于沥青性能的影响,选择常用降黏型温拌剂Sasobit和发泡型温拌剂Asphamin分别加入到基质沥青和SBS改性沥青中,通过针入度、软化点、延度及黏度试验,研究对比这两类温拌剂对沥青感温性能、高低温性能及黏滞性的影响。由等黏温度定理,推算出部分温拌沥青混合料的施工温度,并以此对比分析其降温效果。结果表明:两类温拌剂均能显著提高沥青高温性能,掺入4%Sasobit和4%Aspha-min能使沥青软化点分别增长48%和31%,均可有效降低沥青的高温黏度和压实温度(降温范围在18～24℃之间)。同时,也能提升沥青的低温黏度(95℃下分别提升278%和14.7%),提高沥青路面抗流动变形的能力。但两种温拌剂对沥青低温性能呈不利影响,且这种不利影响与掺量呈正相关,因此应合理控制温拌剂掺量。     

纯电动物流车电动空气压缩机布置方案研究

电动空气压缩机为纯电动物流车提供压缩气源,以供整车制动及辅助用气装置的使用.文章基于整车性能的受影响程度进行电动空气压缩机布置的多方案分析,从多个维度进行客观评价,选取适合于整车的最优方案.此方法亦可用作其他关键件的布置校核.