Abstract
This paper develops a high-sensitivity flexible eddy current array (HS-FECA) sensor for crack monitoring of welded structures under varying environment. Firstly, effects of stress, temperature and crack on output signals of the traditional flexible eddy current array (FECA) sensor were investigated by experiments that show both stress and temperature have great influences on the crack monitoring performance of the sensor. A 3-D finite element model was established using Comsol AC/DC module to analyze the perturbation effects of crack on eddy currents and output signals of the sensor, which showed perturbation effect of cracks on eddy currents is reduced by the current loop when crack propagates. Then, the HS-FECA sensor was proposed to boost the sensitivity to cracks. Simulation results show that perturbation effect of cracks on eddy currents excited by the HS-FECA sensor gradually grows stronger when the crack propagates, resulting in much higher sensitivity to cracks. Experimental result further shows that the sensitivity of the new sensor is at least 19 times that of the original one. In addition, both stress and temperature variations have little effect on signals of the new sensor.
Highlights
Crack damage has become the main factor to the safety of structures, and connection parts of metal structures are generally stress-concentration areas where cracks are most likely to occur
This paper mainly investigates flexible eddy current array (FECA) sensors for crack monitoring of welded structures under stress and temperature interference
Experimental results show that the sensitivity of the sensor to cracks is so low that stress and temperature variations have great influences on the crack monitoring process
Summary
Crack damage has become the main factor to the safety of structures, and connection parts of metal structures are generally stress-concentration areas where cracks are most likely to occur. Magnetometer (MWM) sensors for damage detection and quality evaluation of metal structures, including blades, turbine pressure vessels, oil pipelines other[15,16,17,18,19]. The of influence of the service environment the sensor output has not vessels, oil pipelines and other structures with complexofcurved surfaces.changes the sensor been studied. In a previous paper [20], the on the output signal of the sensor by affecting the conductivity and permeability of the structures influence of temperature changes on signals of a rosette eddy current sensor is studied. A finite model was the influence of stress, temperature, and crack the output signal element of a traditional established to study the effect of crack perturbation on eddy currents distribution and output signals. The sensitivity of the sensor to cracks was studied using finite element simulation and
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