Account of Temperature Change at Calibration of Air Flow Sensor

The article describes of temperature change consideration during the calibration of air flow sensor for a car engine. The sensor uses a blade made of elastic material with strain gauges applied to the front and the back surfaces, the deformation of which is measured and recalculated into a mass flow of air. They suggested the system of equations whose solution makes it possible to determine the mass flow rate and air temperature according to the known signal values at the measuring bridge output and the measuring circuit resistance. The coefficients of equation system are determined during calibration and then are recorded into the memory of the microcontroller sensor.

Damping Effect of a Passing Vehicle for Indirectly Measuring Bridge Frequencies by EMD Technique

The indirect approach for measuring bridge frequencies from a passing vehicle has become an attractive method recently because it provides mobility, reliability, and safety for setting up sensors in comparison with the traditional method for measurement. In the vehicle–bridge interaction system, it is realized that the bridge frequencies can be identified from the spectral analysis of the passing vehicle. However, there exist many factors affecting the identified results of bridge frequencies, and one key factor is the vehicle damping. This study investigates the effect of vehicle damping on the identification of the first bridge frequency for three different levels of road surface roughness by the empirical mode decomposition (EMD) technique. The numerical experimentation shows the following properties that can be utilized in a field measurement: (1) higher vehicle damping tends to suppress the vehicle frequency, and (2) the use of vehicle damping helps to suppress the effect of rough surface roughness and make the first bridge frequency visible.

A Method of Calculation on Balance Resistance of Measuring Bridge in Strain Test

Considering the scattering difference in resistance of the strain gauge which will cause the bridge unbalance, the designers of strain measurement instrument have to add bridge-balance circuit into the design of measuring bridge in order to eliminate the problem of a DC component output caused by the unbalance. Thus, in the design of the bridge-balance circuit, the selection of balance resistances is of great significance. In this paper, through calculation analysis of the balance bridge, we obtained a couple of ideal values of balance resistances and tested them by experiments. In this condition, the experimental results have shown that the circuit has a great ability of regulation equilibrium. In brief, this paper provides the designers an effective method of choosing the balance resistances.

Experimental Study on the Optimal Layering Position of the Piezocomposite Electricity Generating Element Built-in an Innovative Traffic Load-Measuring Bridge Bearing

The bearings of a bridge are indispensable structural members, which support the superstructure, transfer the loads of the superstructure to the substructure and, accommodate the horizontal and vertical motions of the superstructure caused by all types of loads like traffic. Such traffic loads induce the bridge to vibrate but this energy is wasted. Therefore, a piezocomposite electricity generating element (PCGE) has been introduced in the bearing to exploit effectively this vibrational energy. The bridge bearing with built-in PCGE was seen to be effective for measuring the traffic loads and, detecting eventual overloaded or overspeeding vehicles. In a will to optimize the amount of energy generated by this bearing, this study compares experimentally the amount of electricity produced by the PCGE with respect to its position in the bridge bearing through a series of dynamic loading tests to find out the position of the PCGE providing the most efficient electricity generation.