基于PID控制技术的卫星有效载荷舱包装箱的反共振实现

结合XX-1型卫星有效载荷舱的特点及功能需求,分析了其包装箱在不同环境、交通方式和路况下的振动工况,采用PID控制技术对其进行了反共振补偿,建立了系统状态方程,并通过反共振振幅控制试验对其抑制能力进行了分析。结果表明:提出的主动隔振措施较好地实现了全频域点的减振效果,对卫星有效载荷舱的勤务运输提供了较为理想的防护。     

基于 MEMS 技术的在运弹药加速度记录仪设计

目的实时、准确获取弹药在道路运输、装卸搬运等环节中的受力状态。方法分析弹药在不同运输环节中的力学环境,确定弹药受力方式与类别。在此基础上利用MEMS技术设计一种可以测量3个不同轴向加速度的电容式微加速度计,通过理论分析和模拟仿真验证其工作原理,推导出加速度与输出信号的关系。以微加速度计为核心进行元器件选型搭配与软件方案设计,制作加速度记录仪,搭建测试平台,进行信号检测。结果该加速度记录仪能够实时检测重力加速度变化。结论利用MEMS技术制作的加速度记录仪可以实现对运弹药受力状态的实时监测。     

危险品及其包装分类

随着国民经济的飞速发展,危险货物的种类、数量在不断地增多。据统计,全世界海运总量的40％以上是危险物,所以针对危险货物作出正确的分类定级是必不可少的,然后再按照分类定级选择相应的危险货物的专用包装,才能确保运输安全。危险货物分类:按危险货物的危险性或最主要的危险性分成9个类别,有些类别可再分成项别,类别和项别的号码顺序并不是危险程度的顺序。     

大件运输车-桥耦合动力学分析

特殊大件运输车货质量可达千吨,在判断大件运输车辆能否安全通过桥梁时,以桥梁跨中挠度作为评判标准关键指标。该文以四川德阳市石亭江大桥为例,采用Auto CAD软件对大桥进行建模,而车辆的模型以尼古拉斯全液压平板车组为模版进行建模,然后在ADAMS软件中对车辆与桥梁进行耦合动力学分析,研究不同轴数、轴距、轴线载荷的大件运输车辆通过桥梁时桥梁跨中挠度的变化情况。建立的模型和分析结果可以用于预估大件运输车辆通过桥梁时的跨中挠度,为大件运输车辆桥梁通过性提供定量分析方法。     

小型电机运输包装形式及其器具

论述小型电机产品运输包装按不同的销售对象、不同包装要求、运输路程的远近、运输和装卸环境条件的差异等包装形式分托盘捆包、花格箱包、满板箱包和刨光面板精细包装四个包装档次     

预制式轨道板的纵向布置对轨道交通中车辆振动特性的影响

在对具有轨道板结构的无碴轨道分析基础上，建立了预制式轨道板结构的力学模型，即刚体模型。通过对分布式轨道板结构不同的纵向布置对车辆系统的振动响应影响分析，得到了高架桥无碴轨道中预制式轨道板的合理布置方式。     

一种改进的SWEEP路径策略

针对需求随机的随机车辆路径问题,提出了一种改进的SWEEP路径策略.建立了基于该策略的车辆任务量分配多目标规划模型,给出了求解该模型的启发式算法.通过24个不同规模的VRP问题的仿真实验,证明了提出的任务分配模型和算法具有较强的适用性;改进的SWEEP策略能充分利用运输资源,减少运输成本.     

苹果–EPS泡沫系统冲击响应分析

目的 分析苹果在运输包装环境中的抗冲击性能，并优化苹果–EPS泡沫缓冲包装设计。方法 以80 mm果径洛川富士苹果为研究对象，通过万能压缩试验机对苹果进行压缩试验，得到应力–应变曲线。通过ABAQUS/Explicit建立苹果运输包装系统有限元模型，并进行有限元仿真分析，其中发泡聚苯乙烯有限元模型采用Crushable Foam模型，苹果采用线弹性力学模型。模拟苹果在沿轴竖直摆放和沿轴水平摆放2种摆放方式下跌落时的冲击响应，并分析不同厚度、密度为28kg/m³的EPS泡沫的缓冲效果。结果 得出苹果的弹性模量为2.44 MPa、屈服极限为0.38 MPa。通过模拟仿真分析可得出，EPS泡沫能有效减缓运输过程中冲击对苹果的损伤，并以此为基础得到了针对该包装系统的缓冲设计。结论 通过与龙格–库塔数值分析法的对比可以得出，本研究以试验为基础，结合仿真分析能为相关果蔬运输提供数据支持和参考。     

网络型甩挂运输车辆调度优化研究

目的 为了更灵活地满足不同企业间的配送需求,以提高运输效率。方法 在智能交通背景下,基于RFID、Compass/GPS、通信技术等,以运输成本最小为目标建立模型,利用改进的遗传算法对网络型甩挂运输车辆调度进行优化。结果 以山东省某网络型运输企业联盟为例进行优化调度,通过与普通货车运输比较,优化后的甩挂运输车辆调度方案空载率降低了4.6%,耗油量降低了10.6%,运输总成本降低了25.4%。结论 基于改进遗传算法的网络型甩挂运输车辆调度方案有效提高了运输效率,降低了运输成本,对于促进企业降本增效及环境保护都具有重要意义。     

关于我国警察巡逻勤务的思考—社会治安防控体系建设研究之一

随着警察巡逻体制的建立和完善，巡逻勤务活动对维护社会治安稳定发挥了重要作用，但是由于受诸多因素的影响，警察巡逻勤务还存在一些问题，如何应对和解决巡逻工作中出现的新情况、新问题，进一步提高巡逻质量，增强动态环境下对社会治安的控制能力，成为警察巡逻工作面临的一个现实问题。     

国内包装件在汽车及推车配送环节的振动对比

目的明确推车配送环节的振动水平(PSD曲线),通过对比实验提供汽车与推车配送环节的振动差异数据,为更好地进行运输包装设计提供可靠依据。方法利用路谱记录仪DER-1000进行实验数据的记录。首先通过准备实验明确推车配送环节的加速度均方根(grms)水平;进而制作轻、重2种包装件原型,先后测量推车配送环节不同道路和不同固定状态下的数据以及日照—上海实测汽车配送数据;最后,通过对比相应的grms和PSD曲线,分别对推车配送环节与汽车公路运输环节进行对比分析。结论推车配送环节的振动水平显著高于汽车运输环节,约为公路运输的10倍,在进行实际包装件设计时必须考虑推车配送环节的振动情况。     

运输包装件低气压振动模拟试验方法

目的 在常温下通过控制低气压和振动双危害因素,研究一种模拟运输的试验方法,用于评估物流包装对产品的保护性能.方法 研发一种低气压振动试验装置,将其与振动系统相结合,在实验室内模拟高原运输或飞机运输中的低气压环境条件.实现一种能够在特定的温湿度下控制低气压和振动综合环境因素的试验方法.结果 低气压振动试验系统能够满足ISTA 3A中的试验要求,根据国内外低气压试验标准和随机振动试验标准,制定了低气压振动综合试验方法.结论 对于评价高海拔卡车、铁路和航空运输包装件的模拟试验提供了可行性依据.     

Vibration and acceleration levels of multimodal container shipping physical environment

In global supply chains, multimodal transportation plays a dominant role in worldwide shipping. The rail, truck, and vessel combination is the most commonly used mode for non‐time sensitive shipments between continents. This study focused on measuring the transportation environment effects (vibration and acceleration levels) in 40‐foot ISO container shipments using multiple modes of transport, originating in Hungary and destined for Mexico, India, and China over several weeks. The study also measured multimodal shipping routes without vessel transportation to China over Trans‐Siberian and Trans‐Manchurian railway lines. The transshipments and handling events in container hubs and terminals were separately analyzed. The results show the comparison of vibration intensity (in PSD) of different route conditions between various continents, and the possibility of acceleration levels during transshipments and handling events. The measured data show that extreme acceleration levels in vertical direction (9.37 G) occur while containers are handled in a seaport, and in lateral (4.45 G) and longitudinal (5.55 G) directions while they are transshipped by truck to rail container terminals. The rail vibration levels in Russia and China showed a lower intensity in the frequency range of 1 to 15 Hz, and higher between 15 and 200 Hz than in Europe; the lowest vibration levels occurred when the containers traveled on the sea, and truck vibration levels were very similar to previous research and ISTA protocols.     

Measurement and analysis of truck transport environment in Brazil

Increasing trade in today's global economy requires packaging to be designed to contain, protect and deliver products without damage during transportation and handling. Vibration forces that occur during transportation are one of the most significant causes of damage during shipping. The objective of this study was to quantify and analyse the vibration that occurs during truck transport in Brazil. The study was done using two types of trucks: small local trucks for local metropolitan distribution areas and larger tractor‐trailers for cross‐country transportation. Ten metropolitan areas in different regions of Brazil were selected for 1‐day trips representing normal delivery. These trips encountered varying road surfaces (asphalt, concrete, stone and dirt). The long distance trips were done on highways that were more than 1200 km long. The vertical vibration levels were higher than the lateral and longitudinal levels as expected. A composite power density spectrum of all trips is provided in this paper to simulate truck transport in Brazil using random vibration test methods. Copyright © 2007 John Wiley & Sons, Ltd.     

Measurement and analysis of truck and rail vibration levels in Thailand

Worldwide increase in trade, foreign direct investment, capital flows, migration and the spread of technology has caused an increased focus to be put on designing packages that can protect goods shipped globally. This requires a wide‐ranging understanding of the distribution environments on a global basis. Several past studies have mapped the vibration levels for surface transportation along the most popular shipment routes in countries such as Brazil, Canada, China, India and the USA. This study was conducted to provide a comprehensive understanding of the vibration levels observed for truck and rail shipments for major transportation routes in Thailand, one of the leading economies in the Southeast Asia region. Data recorders were used to collect the vibration data which were then analysed in terms of power spectral densities. Vibration levels observed from various segments of transportation are presented in the form of power density spectrums. Composite spectrums that can be used to simulate the measured vibration conditions in Thailand are presented. Copyright © 2010 John Wiley & Sons, Ltd.     

Test protocol for simulating truck and rail vibration and rail impacts in shipments of automotive engine racks

A study of the truck and rail transport environments using racks containing Ford engines was conducted to quantify shock and vibration levels during shipment. Tri-axial acceleration data was collected at several locations on the floor of the vehicles and on the racks themselves to determine the severity of shock and vibration input from truck trailers and rail boxcars. Power Spectral Density plots were developed from the data collected and used to simulate truck and rail shipments on an electro-hydraulic vibration table. The results showed that the highest vibration levels in the steel racks occurred at 4 Hz in the vertical direction for truck shipments, and between 12–16 Hz for rail shipments. The vibration levels in the longitudinal and lateral directions were much lower than in the vertical direction for truck shipments. The most severe shock to a rack in rail shipments was 5.7 G peak in the longitudinal direction as a result of coupling.     

Effect of vehicle speed on shock and vibration levels in truck transport

An update on the nature of shock and vibration in truck transport was obtained by measuring and analysing the shock and vibration levels separately that occur during truck transportation in Japan. The effect of truck speed on the shock and vibration levels was mainly analysed. A significant difference was observed between the acceleration of vibration, and the acceleration including shock and vibration as a result of truck speed. The results indicated that the effect of truck speed on root mean square acceleration (Grms), including shock and vibration, was strong at a lower speed, but slight at a higher speed. The highest Grms, including shock and vibration, was found at 45–59.9 km/h on local roads, which was higher than that during highway driving. When the speed was below 45 km/h, the peak power spectral density (PSD) of acceleration including shock and vibration increased as truck speed increased; when the speed was above 45 km/h, no significant changes in peak PSD were found because of truck speed. At the same time, the effect of vehicle speed on the vibration acceleration was also studied. It was found that the higher the vehicle speed, the higher the Grms and peak PSD value of vibration in both the vertical and lateral directions. Copyright © 2010 John Wiley & Sons, Ltd.     

Measurement and analysis of vibration levels for express logistics transportation in South China

Trunk transportation and terminal distribution are two important parts of express delivery in China. Heavy truck and medium truck are two main vehicles of trunk transportation. Mini van and two‐wheel electric bicycle are widely used for terminal distribution. Four vehicles mentioned previously and a sedan car were chosen for vibration level measurement and analysis in this paper. The results revealed that vibration levels were significantly higher in the vertical axis, and decreased with the increase of payload, and increased with the increase of speed again. Similar power spectral density peak frequencies were found in a comparison study with previous results in the low‐frequency region (1‐10 Hz), occurred at approximately 2 Hz in the van and sedan car and at 3 to 4 Hz in the truck and at 4 to 5 Hz in the two‐wheel electric bicycle. Except the two‐wheel electric bicycle, the second peak frequency occurred at approximately 20 to 30 Hz in the sedan car and at 10 to 20 Hz in the mini van and at 20 to 40 Hz in the heavy truck, which were also similar to the previous studies. Vibration levels of the sedan car were the lowest, and the trunk transportation vehicles (heavy truck, medium truck) were the highest. The terminal distribution vehicles (mini van, two‐wheel electric bicycle) were somewhere in the middle.     

Measurement and analysis of truck transport vibration levels and damage to packaged tangerines during transit

The purpose of this study was to measure the vibration levels in commercial truck shipments in Thailand and observe the effects on packaged fruit. The study measured the vibration levels in two of the most commonly used truck types to ship packaged goods as a function of road condition and vehicle speed. The suspension type on the trailers studied was leaf‐spring. The results of damage to packaged tangerine fruit as a function of location in the payload are also presented. The data presented in this study will assist product and package designers to reduce damage in transit. The results showed that vibration levels increased with speed and as a result of road condition. Analysis of variance indicated that three controlling factors, road surface, truck speed and truck type, significantly affected (p ≤ 0.05) peak PSD, PSD* (root mean square) over the frequency range 2–5 Hz, and fruit damage. As expected, based on previous work, an increase in truck speed resulted in an increase in vibration levels and damage to packaged fruit. The laterite road condition produced the highest vibration level for a given truck and travelling speed followed by concrete highway and asphalt road conditions. Fruit damage was found to be greatest in the uppermost container for every combination of road, truck type and travelling speed, which also corresponded to the highest vibration levels recorded. The results showed that a significant amount of damage can occur on unpaved roads (laterite), while the packages are transported from farms and harvesting areas to regional truck terminals. Damage on asphalt road conditions was minimal. This paper provides an updated history of measured and quantified levels of vibration for these specific trucks and road conditions. Copyright © 2005 John Wiley & Sons, Ltd.     

Measurement and analysis of truck and rail shipping environment in India

Free trade agreements have been on the rise in all regions of the world in the past decade. This has allowed for global distribution and marketing of products in an international market. Products once produced for domestic markets must now be able to compete in international markets without trade barriers. Increased international commerce and manufacturing have forced many packaging and logistics engineers to broaden their true understanding of the global distribution environment. India is a recent entrant on the global arena for manufacturing and services. While China's economic developments have dominated global headlines, India's own growth has been impressive as well, with a gross domestic product rising 5% per annum on average since 1990. India is hence primed to follow China as the next low‐cost manufacturing super power. With an increasing interest from multinational corporations in conducting commerce with India, there arises a great need to understand the conditions of the transportation infrastructure there to promote logistical understanding of the distribution environments. This paper provides a brief overview of the road and rail transportation environment in India. It also provides the results of a 2 year study that measured and analysed truck and rail transport vibration for the major freight distribution routes between New Delhi, Bangalore, Mumbai, Chennai, Hyderabad and Kolkatta. Copyright © 2007 John Wiley & Sons, Ltd.