Developing a New Vibration Analysis Calculative Method for Esfahan Subway Train and Railways Design, Manufacturing and Construction
The simulated mass and spring evaluation for subway or railways construction and installation have wide applications in rail industries. This kind of design should be optimize all related parameters to reduce the amount of vibration in cities, residential areas, historical zones and other critical locations. Finite element method used too much to analyze such applications with an excellent accuracy but developing some simple, fast and user friendly evaluation always was required in subway industry. In addition, process parameter optimization required in railways to achieve optimal railways design with maximum safety, reliability and performance. The simple but useful simulated mass and spring evaluation system developed for Esfahan subway construction. This method discussed in this paper. Esfahan subway construction has a historical zone. Historical buildings should protect from harmful vibrations. Polyurethane layer used to reduce vibrations. This layer completely covered by concrete layers in all directions. It is worthy to know that, all the operation criteria like displacement and stress could be adapted with all vibration criteria like natural frequency, operation frequency and damping. Adaptation performed by changing in polyurethane layer thickness. The results showed that if 25-millimeter thickness polyurethane layer covered completely by two concrete layers with 12 millimeter thickness, the amounts of vibrations reduce considerably. In addition, it strongly recommended increasing the polyurethane layer up to 37 millimeter in historical zone to prevent potential harmful effects. The results confirmed by other commercial methods. The calculative method successfully performed. Furthermore, it is important to reduce maintenance costs in any potential design. The process parameter like rail ways dimension, rail ways material, cabins loading, cabins quality, cabins dimension and polyurethane layer thickness properly designed to keep the subway natural frequency around 18 Hz ( less than allowable 20 Hz). Numerical design results will protect all historical buildings, palaces paintings and old bridges in future subway operation times. In addition, some interesting patent and innovation in rail industry like Suspension mass tuned vibration reducer, short sleeper vibration-attenuation fastener and airtight track vibration noise reducing fastener discussed in this paper.
Use of railway track vibration behaviour for design and maintenance
Components applied in a railway track structure (e.g. rails, fastening systems and supports) are significantly influencing the vibration behaviour of this so-called ‘superstructure’. Superstructures for trams, metros and trains can be classified on the impact that the vibration behaviour has on the wheel-rail interaction and on sound radiation. Methods for recording, simulation and analysis have been developed to perform an assessment, which supplies track managers with arguments on track design and track maintenance.
Variability of Reflectance Measurements with Sensor Altitude and Canopy Type
Data were acquired on canopies of mature corn planted in 76 cm rows, mature soybeans planted in 96 cm rows with 71 percent soil cover, and mature soybeans planed in 76 cm rows with 100 percent soil cover. A LANDSAT band radiometer with a 15 degree field of view was used at ten altitudes ranging from 0.2 m to 10 m above the canopy. At each altitude, measurements were taken at 15 cm intervals also a 2.0 m transect perpendicular to the crop row direction. Reflectance data were plotted as a function of altitude and horizontal position to verify that the variance of measurements at low altitudes was attributable to row effects which disappear at higher altitudes where the sensor integrate across several rows. The coefficient of variation of reflectance decreased exponentially as the sensor was elevated. Systematic sampling (at odd multiples of 0.5 times the row spacing interval) required fewer measurements than simple random sampling over row crop canopies.