以海泡石为基材的汽车制动摩擦片的研制

为了减少环境污染,充分开发和利用我国的自然资源,研制成功了以海泡石为基材的非金属汽车制动摩擦片。这种摩擦片具有较高的摩擦磨损性能,生产工艺简单,工艺条件与用石棉作为增强纤维时的工艺条件类似。不仅质量轻,而且价格便宜,具有广阔的市场前景。     

AMT车辆制动工况换挡控制策略与试验

提出了根据发动机转速信号来识别不同制动工况的方法,制定了相应的换挡控制策略,并在装有AMT的某重型载货汽车上进行了实车制动试验。试验结果表明,制动上况下的换挡控制策略不仅符合车辆实际行驶工况的需要,而且符合驾驶员的制动意图。     

轻型桥台计算的探讨

轻型桥台是高速公路小桥涵普遍使用的结构型式。采用两种计算模型,对钢筋混凝土轻型桥台的配筋进行比较计算,以了解两种模型的合理性,通过两种模型的偏心受压计算,验证了目前采用的桥台截面满足设计要求。     

长江口深水航道治理工程灯浮系碇配置方案

总结长江口水域灯浮系碇设置和管理的经验,对长江口深水航道治理工程特定水域条件下,对灯浮系碇配置方案可行性进行了设计计算。     

搅拌摩擦点焊技术及在汽车工业应用前景

搅拌摩擦点焊(FSSW)技术是在“线性”搅拌摩擦焊接(FSW)基础上开发的一种新的焊接技术。在焊接铝、镁等轻合金方面,FSSW与传统电阻点焊相比具有焊点强度高、质量好、工艺简单、焊接工具寿命长、节省能源及成本低等优势。对搅拌摩擦点焊的基本原理、工艺特点及在汽车工业中的应用现状及前景进行了阐述。     

制动抖动引起的转向盘振动传递途径分析

建立了基于ADAMS/CAR的多刚体车辆动力学仿真模型,成功再现了制动引起的转向盘振动现象,并与试验结果具有良好的一致性。通过信号时域和频域分析,明确了振动从制动器到转向盘的传递途径,提出了调节橡胶弹性元件刚度的振动控制方法。     

盘式制动器制动抖动现象机理研究

介绍某轿车的制动抖动试验情况,根据实测的制动盘几何特征建立数学模型,从理论分析该车制动时转向盘抖动是因制动盘端面跳动过大。同时还分析制动盘厚薄差和端面跳动对制动抖动的影响。分析结果表明,制动盘厚薄差对制动抖动的影响大于端面跳动的影响,并且两者之间还存在着相位匹配的关系。     

Integrating land use and transport practice through spatial metrics

Despite the growing development of tools that can integrate land use and transport, the desired integration is still illusive in daily practice. To address this gap, the current study uses spatial metrics, a set of methods traditionally used for studying changes in the spatial structure of landscapes, which are translated into the domain of transport planning. It examines how spatial metrics can be integrated into “Land Use Transport” strategy-making, and how useful they are according to the practitioners’ perceptions. A Light Rail Transit corridor in Granada (Spain) provides the empirical focus of this research. Land use characteristics such as: land use mixing, land use diversity and green areas connectivity were successfully studied using spatial metrics, and they were used to map three “Land Use Transport” strategies: (i) proximity dynamics and non-motorised modes; (ii) modal shift from cars to Light Rail Transit system; (iii) shared spaces between motorised and non-motorised modes. Practitioners perceived that spatial metrics could improve the “Land Use Transport” strategy-making process in comparison with traditional methods used in practice. However, certain shortcomings related to the usability of spatial metrics are also highlighted and discussed. This study concludes with a reflection on research challenges for adapting spatial metrics to transport practice.     

Time-based life-cycle assessment for environmental policymaking: Greenhouse gas reduction goals and public transit

As decision-makers increasingly embrace life-cycle assessment (LCA) and target transportation services for regional environmental goals, it becomes imperative that outcomes from changes to transportation infrastructure systems are accurately estimated. Greenhouse gas (GHG) reduction policies have created interest in better understanding how public transit systems reduce emissions. Yet the use of average emission factors (e.g., grams CO₂e per distance traveled) persists as the state-of-the-art masking the variations in emissions across time, and confounding the ability to accurately estimate the environmental effects from changes to transit infrastructure and travel behavior. An LCA is developed of the Expo light rail line and a competing car trip (in Los Angeles, California) that includes vehicle, infrastructure, and energy production processes, in addition to propulsion. When results are normalized per passenger kilometer traveled (PKT), life-cycle processes increase energy use and GHG emissions up to 83%, and up to 690% for smog and respiratory impact potentials. However, the use of a time-independent PKT normalization obfuscates a decision-maker’s ability to understand whether the deployment of a transit system reduces emissions below a future year policy target (e.g., 80% of 1990 emissions by 2050). The year-by-year marginal effects of the decision to deploy the Expo line are developed including reductions in automobile travel. The time-based marginal results provide clearer explanations for how environmental effects in a region change and the critical life-cycle processes that should be targeted to achieve policy targets. It shows when environmental impacts payback and how much reduction is achieved by a policy-specified future year.     

The cost of convenience; Air pollution and noise on freeway and arterial light rail station platforms in Los Angeles

Light rail transit (LRT) systems constitute one of the most sustainable public transportation modes and transit agencies have increasingly constructed LRT lines along the median of roadways to reduce land acquisition costs and traffic conflicts. Despite these conveniences, few studies have examined the air pollution and noise exposures for passengers on LRT station platforms within freeway or arterial medians. In response, we monitored particle number count (PNC) concentrations and noise levels on 17 station platforms in the Los Angeles metro system in summer 2012 and assessed differences between freeway and arterial platforms. We visited each station on average 7 times for approximately 19 min with two teams carrying a full set of instruments. As expected, impacts were higher on green line platforms in the center of a grade-separated freeway compared to blue line platforms in the center of an arterial due to being in close proximity to greater traffic volumes. Overall, freeway-arterial platform differences were 35,100 versus 20,000 particles/cm³ for PNC and 83 versus 62 dBA for noise. This average noise intensity on green line platforms was four times that on blue line stations. We also found that PNC concentrations were significantly higher at open air monitoring platform positions compared to standing under a shade canopy (about 2000 particles/cm³ higher), but that noise levels were significantly lower at open air positions compared to under canopy positions (about 3.2 dBA lower). Results identify important factors for transport planners to consider when locating and designing in-roadway LRT platforms.