Strain gauges debonding fault detection for structural health monitoring

Abstract

Physical redundancy is a common approach in applications with safety-critical systems. But that is not always possible in some structural health monitoring (SHM) applications whether for economic, spatial, or safety reasons. Many SHM sensor validating applications only rely on analytical redundancy. In such circumstances, sensor faults and structural damage need to be assuredly discriminated. A self-diagnosis strain sensor operating in a continuous online SHM scenario is considered. The sensor is based on a full electric resistance strain gauge Wheatstone bridge. The state of the art shows that such a sensorhas not yet been developed. The loop current step response (LCSR) is a wellknown method to detect strain gauge debonding. However, applying the LCSR method to a full strain gauge Wheatstone bridge has some limitations analyzed in this paper. Two new methods for detecting strain gauge debonding are proposed and evaluated. These methods are based on consistency checking of the strain gauges grids temperature measurements-employing an array of (a) digital contact temperature sensors or (b) quasi-contact microelectromechanical system thermopile sensors. The experimental results reveal that both methods are suitable for application in an SHM self-diagnosis sensor scenario. However, the quasi-contact measuring method showed to be more sensitive to the strain gauge grid debonding fault though.KEYWORDS loop current step response (LCSR) method, self-diagnosis sensor, strain measurement, temperature measurement, thermal sensors

Measurement of Acceleration Response Functions with Scalable Low-Cost Devices. An Application to the Experimental Modal Analysis

“…Certain specific SHM applications require the use of other types of sensors. For example, strain gauges are widely used to monitor strain and stress variations [ 19 , 20 ]. Displacements can be measured by means of Linear Variable Differential Transformers (LVDTs) [ 21 ], or in certain situations, a combination of accelerometers and a Global Position System (GPS) [ 22 , 23 ].…”

“…Displacements can be measured by means of Linear Variable Differential Transformers (LVDTs) [ 21 ], or in certain situations, a combination of accelerometers and a Global Position System (GPS) [ 22 , 23 ]. Finally, sensor hybridization techniques are also interesting to detect potential sensor damage or failure [ 20 ].…”

Critical Experiments for Structural Members of Micro Image Strain Sensing Sensor Based on Smartphone and Microscope

“…The structural strain plays a significant role in the structural health monitoring (SHM) system, as it could intuitively reflect the local characteristics of the structure and easily perform the structural safety assessment [1][2][3][4]. Currently, the strain sensors for SHM commonly include electrical resistance strain gages (ESGs) [5][6][7], fiber optic strain sensors (FOSs) [8][9][10][11], vibrating wire strain gages (VWSGs) [12,13], and digital imaging correlation (DIC) [14][15][16][17]. Among these sensors, ESGs are usually required to form a measurement circuit with wires, which would cause complicated situations when there are many measurement points and is subject to electromagnetic signal interference.…”

New Sensing and Radar Absorbing Laminate Combining Structural Damage Detection and Electromagnetic Wave Absorption Properties

“…In general, SHM systems use various types of sensors. Among them, foil strain gauges are widely used [ 14 ], although they have limitations in terms of 2D-spatial deformation detection, sensitivity to temperature variation, and fatigue cycles. Another class of sensors are those based on optical-fiber technology, in particular fiber Bragg grating (FBG) [ 15 ].…”