| Keep on developing of nation economy, the government increases investment of main highway year by year. From the 1988 Shenyang-Dalian, Shanghai-Jiaxing expressway opening, our country realizes breakthrough in expressway. Government invested 218.8 billion in 1998, meanwhile expressway mileage reached 6258 km by that time. There are 19 thousand km statistics according to the Ministry of Transportation & Communications.When the vehicle is driven, the roughness of the road will increase the automotive vibration. When this kind of vibration gets the certain degree, will make passenger feeling uncomfortable with tired, or make the goods damage that carry. At same time, the motion load that road arises will reduce vehicle life and friction coefficient. The motion load also affects vehicle's steering and handing performance. Increasing vehicle operating speed is an important path to increase transportation efficiency, but this will make vehicle vibration worse. If transportation meet the need of comfortable,reliability and safety at same time, we have to adopt the valid measurement: Firstly we must improve quality of highway surface in order to reduce source of vibration, secondly the performance of vehicle comfortable is good. The vehicle engineering side only consider excitation caused roughness of road so that all of the excitation should be accounted into roughness, then road class divides according to roughness. Highway class set off by road operation condition in our country. There are not direct relation between roughness and road class. When vehicle is running, vibration and active load caused by road roughness, these add transportation cost. Road roughness is both important parameter of Present Serviceability Index, abbreviation is PSI and important reference drawing running criterion of proving ground. Using vertical section real profilometer made by Chang-Chun automobile research institute, select a section of a representative highway of Beijing to tianjin expressway, Beijing to shijiazhuang expressway, proving ground for highway and traffic of MOC. ,Hai-nan proving ground, measured road profile roughness data and meanwhile collected most power spectrum data about Hai-Nan expressway and ShenYang-Dalian expressway .According ISO/DIS 8608 road profile-report method of measurement standard ,data parameter expressing power spectrum. It include frequency structure of power spectrum ,different frequency range . Afterward collection data ,data integral, pre-processing analyzing, Statistic analyzing, gained road profile chart, cumulative curve ,distance power spectrum density and international road index. Conclusion indicate relation between highway macro quality and power spectrum, , w, international road index etc. Conclusion as underside:Paper analysis power spectrum of 13 high grades highway or expressway, Power density and IRI are important method for highway surface quality evaluation. Result include power density curve,road profile and accumulation curve.Although they are high grade highway, their road surface quality is different. We can see the difference from road profile diagram. The best sample(figure is 3 mm) is high speed track of proving ground of MOC. The worst sample(figure is 15.6mm) is high speed track of Hai-nan proving ground. The roughness of same road is quite variable, because of different sample. Roughness of Three different sample in Shenyang-Dalian expressway is same level. Max value is between 4 and 5mm .The other sample is very different. For example , the roughness of Hainan freeway is from 5.6to 15.6 . When pretreatment data (sample length)is different, max value is different and we don't ignore these. Displacement Power density and accumulation curve include same information, linearity coordinate and accumulation is very easy analysis. Several curves can plot in a picture so that analysis is convenient.According to figure 4 to 5, total power of highway surface is under C line. Most of power is between A and B line. It indicates that measurement and ana...
|
PDF Full Text Request