Remotely detected vehicle mass from engine torque-induced frame twisting
Abstract. Determining the mass of a vehicle from ground-based passive sensor data is important for many traffic safety requirements. This work presents a method for calculating the mass of a vehicle using ground-based video and acoustic measurements. By assuming that no energy is lost in the conversion, the mass of a vehicle can be calculated from the rotational energy generated by the vehicle’s engine and the linear acceleration of the vehicle over a period of time. The amount of rotational energy being output by the vehicle’s engine can be calculated from its torque and angular velocity. This model relates remotely observed, engine torque-induced frame twist to engine torque output using the vehicle’s suspension parameters and engine geometry. The angular velocity of the engine is extracted from the acoustic emission of the engine, and the linear acceleration of the vehicle is calculated by remotely observing the position of the vehicle over time. This method combines these three dynamic signals; engine induced-frame twist, engine angular velocity, and the vehicle’s linear acceleration, and three vehicle specific scalar parameters, into an expression that describes the mass of the vehicle. This method was tested on a semitrailer truck, and the results demonstrate a correlation of 97.7% between calculated and true vehicle mass.
Shear force–based method and application for real-time monitoring of moving vehicle weights on bridges
A new approach for monitoring the weight of trucks in motion using the bridge response is introduced in this article. The proposed technique is based on the use of strain rosettes for acquisition of shear strains near bridge supports. Bridge weigh-in-motion monitoring using shear force is a new approach that differs from the prevailing techniques based on the measurement of flexural strains. Formulations are introduced using the shear force response of the bridge in the computation of gross vehicle weights. The method requires truck speeds, influence lines, and shear force responses for the computation of gross vehicle weight. All these are acquired by two sets of rosette sensors attached in series on the webs of bridge girders. An experimental program was designed to evaluate the response of the proposed approach in real-time monitoring of moving truck weights. This was accomplished by instrumentation and load testing of a two-span prestressed concrete box girder bridge by a calibrated truck. Field test results are presented and compared with the actual weight of the calibrated truck.
Laminar heat or mass transfer in rectangular channels and in cylindrical tubes for fully developed flow: comparison of solutions obtained for various boundary conditions
Abstract A comparison is made of results obtained with various boundary conditions at the wall of the channels. By comparing blood Sherwood numbers for finite wall resistance with those for constant concentration boundary condition only a small variation is found for various points along the blood channel.