A Novel Strain Measurement System in Strong Electromagnetic Field

As a new approach to shale gas exploitation, electrical explosion shock wave has become a research hotspot in recent years. Strain measurement plays an essential part in electrical explosion research. However, in conventional strain measurement, the spatial electromagnetic interference produced by the discharge could affect the measurement accuracy, or even damage experimental instruments. For strain measurement in a strong electromagnetic field, a novel strain measurement system, based on resistance strain gauges and a designed conditioning circuit, was tested and evaluated. The compensation method was used to eliminate the intense interference, and a five-order Butterworth low-pass filter was designed and implemented to remove high-frequency noise. Simulation and experimental results showed that the strain could be expediently figured out by measuring the output voltage of the conditioning circuit. And in the strong electromagnetic field, dynamic strains varied from 860 με to 1400 με were measured by the novel system in both axial and circular directions.

I. Introduction

With the development of global economy, energy structure changes constantly. Shale gas resources, as a kind of resource-rich environmentally friendly energy, possess high economic value [1]. Based on the high-power pulse technology and application of the electrical pulse devices to counter electrohydraulic effects [2], electrical explosion shock wave (EESW) is serving as a new method of shale gas exploitation.