Shape optimization of rubber isolators in automotive cooling modules for the maximization of vibration isolation and fatigue life

Rubber isolators are mounted between a cooling module and a carrier to isolate the car body from vibration due to the rotation of the cooling fan. The isolators should be durable against fatigue loads originating from fan rotation and road disturbance. Thus, the design of rubber isolators is required to maximize both vibration isolation and fatigue life. In this study, the shapes of the rubber isolators are optimally designed using a process integration and design optimization (PIDO) tool that integrates the various computer-aided engineering (CAE) tools necessary for vibration and fatigue analyses, automates the analysis procedure and optimizes the design solution. In this study, we use CAE models correlated to the experimental results. A regression-based sequential approximate optimizer incorporating Process Integration, Automation and Optimization (PIAnO), a commercial PIDO tool, is employed to handle numerically noisy responses with respect to the variation in design variables. Using the analysis and design procedure established in this study, we successfully obtained the optimal shapes of the rubber isolators in two different cooling modules; these shapes clearly have better vibration isolation capability and fatigue lives than those of the baseline designs used in industry.     

Dynamic analysis of spiral bevel geared rotor systems applying finite elements and enhanced lumped parameters

The dynamics of spiral bevel gears like most high-speed precision gears employed in motor vehicles and off highway equipments are substantially affected by the structural characteristics of the shafts and bearings. The lumped parameter model is one of the common tools applied to perform gear dynamic analysis. Even though the lumped parameter approach is computationally fast and conveniently efficient, it typically uses limited number of coordinates and may not fully account for the shaft-bearing structural characteristics accurately. In this analysis, the finite element formulation, that can generally represent more complete characteristics of the shaft-bearing assembly, is employed to enhance the current lumped parameter synthesis theory using the concept of effective mass and inertia elements. Computational output shows that the enhanced lumped parameter synthesis model is capable of predicting sufficiently accurate dynamic response when compared to the direct dynamic finite element calculations, and much more precise response than previous lumped parameter results, especially when the gear dynamics are associated with the pinion or gear bending modes. Even though this analysis focuses primarily on the spiral bevel geared rotor systems, the proposed methodology and analysis results can be easily extended to other types of gears.     

Investigation of particle emission characteristics from a diesel engine with a diesel particulate filter for alternative fuels

Particle number measurement is a new approach to determine emission, which may be more accurate at very low emission levels than when using gravimetric measurements. An experimental study was performed to investigate the effect of fuel properties on the performance, combustion process, regulated gaseous emissions and particle number emissions of a diesel engine with an uncatalyzed diesel particulate filter (DPF). The effect of the filter on the particle size distribution was reported. The DPF number-based filtration efficiency in terms of number efficiency and fractional efficiency for petroleum diesel fuel and two alternative fuels, BTL and GTL, were analyzed. For nearly all test modes, the filter had a higher number efficiency for diesel than for BTL and GTL. The DPF fractional efficiency showed it was highly dependent on fuel type and varied widely at each size range. For diesel, the filter fractional efficiency was sufficiently high and behaved as predicted by filtration theory. For BTL and GTL, the fractional performance of the filter decreased when unexpectedly low efficiencies within the nuclei mode were exhibited. This research will be helpful in understanding DPF number-based filtration performance for alternative fuels and will provide information for the development of particulate emission control technology.     

Technology analysis and low-cost design of automotive radar for adaptive cruise control system

Recently, the advanced driver assistance system (ADAS), which helps mitigate car accidents, has been developed using environmental detection sensors, such as long and short range radar, lidar, wide dynamic range cameras, ultrasonic sensors and laser scanners. Among these detection sensors, radars can quickly provide drivers with reliable information about the velocity, distance and direction of a target obstacle, as well as information about the vehicle in changing weather conditions. In the adaptive cruise control system (ACCS), three radar sensors are usually needed because two short range radars are used to detect objects in the adjacent lane and one long range radar is used to detect objects in-path. In this paper, low-cost radar based on a single sensor, which can detect objects in both the adjacent lane and in-path, is proposed for use in the ACCS. Before designing the proposed radar, we analyzed the world-wide radar technology and market trends for ACCS. Based on this analysis, we designed a novel radar sensor for the ACCS using radar components, such as an antenna, transceiver module, transceiver control module and signal processing algorithm. Finally, target detection experiments were conducted. In the experimental results, the proposed single radar can successfully complete the detection required for the ACCS. In the conclusion, the perspective and issues in the future development of the ACCS radar are described.     

俄罗斯中部地区在国际运输走廊发展中的角色

许多理论研究以及实践结果表明,中部地区的地理位置可以在全球经济市场和一体化的运输体系中成为该地区的主要竞争优势,认识不足或忽视空间地域因素在经济发展中起到的作用,将导致在管理决策上作出错误的判断.本文研究乌拉尔联邦区作为俄罗斯联邦中部地区在国际运输走廊发展中的角色.     

Solving Nonlinear Differential Equation Governing on the Rigid Beams on Viscoelastic Foundation by AGM

In the present paper a vibrational differential equation governing on a rigid beam on viscoelastic foundation has been investigated. The nonlinear differential equation governing on this vibrating syst...     

电喇叭振动疲劳分析

通过振动疲劳试验规范得到功率谱密度数据,以此作为输入,利用频响分析和疲劳分析等CAE分析方法,对该车型电喇叭及其支架在试验功率谱谱作用下的振动疲劳寿命进行分析计算,同时与试验结果进行对比。     

Developing MPA Effectiveness Indicators: Comparison Within and Across Stakeholder Groups and Communities

Shared expectations about marine protected areas (MPAs) might be expected to enhance their effectiveness. This study determined whether members of local communities had common or divergent views about the objectives and indicators of MPA effectiveness. In the central Philippines we used unconstrained and constrained methods to interview people in five stakeholder groups (elders, fishers, leaders, women, and youth) associated with each of 10 community-based no-take MPAs that had been protected between 0 and 21 years. Respondents identified multiple MPA objectives, the most frequently mentioned of which was restoring and sustaining fish populations. The results suggest that MPA age accounts for the greatest level of variation across communities. When unconstrained, progress in enforcement was identified as a key indicator among respondents from younger MPAs while respondents from older MPAs identified increased fish abundance and catch. Although consensus can be reached more easily under constrained conditions, the results derived from unconstrained methods are more revealing of the needs and aspirations of communities. These are likely to contribute more to the search for appropriate management interventions, particularly given that MPAs evolve over time. Hence, the development of MPA effectiveness indicators must be an iterative community-informed process to ensure timely and relevant management interventions.     

Towed-Diver Surveys,a Method for Mesoscale Spatial Assessment of Benthic Reef Habitat: A Case Study at Midway Atoll in the Hawaiian Archipelago

An integrated method for benthic habitat assessment is described, in which divers maneuver boards equipped with digital video, temperature, and depth recorders while being towed behind a small boat. The tow path is concurrently recorded by a GPS receiver, and a layback model is applied to more accurately map the data. Percent cover of salient benthic categories is quantified by whole-image analysis of still frames sampled at 30-s intervals. The results of 15 towed-diver surveys at Midway Atoll in the Hawaiian Archipelago during a mass coral bleaching event are presented to exemplify the method and are compared to results derived from conventional methods. Towed-diver surveys bridge a gap between large-scale mapping efforts using satellite data and small-scale, roving diver assessments, providing a mesoscale spatial assessment of reef habitats. The spatial coverage of towed-diver surveys provides comprehensive data to managers concerning the extent, intensity, differential taxonomic response, and bathymetric correlates of bleaching.     

The role of the Federal Government in US marine transportation

The United States meets the world shipping crisis of the 1970s with a high-cost merchant fleet and a national maritime policy which needs clearer articulation. This paper examines the objectives, rationale and methods of implementation of the Us maritime programme with attention, finally, to the question of governmental reorganization.