Effect of Embedded Strain Gage on the Mechanical Behavior of Composite Structures

Abstract

A B S T R A C TFiber reinforced composites are increasingly used in several fields such as aeronautics and civil engineering due to their increased strength, durability, corrosion resistance, resistance to fatigue and damage tolerance characteristics. The embedding of sensor networks into such composite structures can be achieved. In the present study, glass fiber reinforced Epoxy composite with integrated strain gage was analysed. Firstly, the mechanical behaviour of this material with embedded strain gage is investigated. The as-prepared samples have been tested under tensile and flexural loading in order to study the effects of the strain gage embedding on the structural stiffness and strength of the composite. It was found that the tensile stiffness decreases by 5.8% and the tensile strength decrease by 1.5% when the strain gage embedded in the material. On the other hand, the flexural strength and stiffness is increased, respectively, by 1.5% and 5.5% with an embedded strain gage. The experiments showed that embedded strain gage is functional and demonstrated the successful integration of sensor networks into composite parts. The obtained results confirm that integrated strain gage can be used for the Structural Health Monitoring (SHM) of glass fiber reinforced Epoxy composite.

On the Identification of Local Structural Defects in Composite Thin-Walled Structures

“…The obtained results show the qualitative agreement between the experiment and the numerical analysis (cf. modes 1,4,5,6,8). It can be seen that the frequency changes are non-linear, and they are more prominent the greater the damage (hole) is.…”

“…The task of the measuring system is to provide the right amount of information that is the basis for quick repairs. A similar task must be fulfilled by a concept based on a modal analysis implemented with an impact hammer [4,17,23]. The research was supported by a comparative numerical analysis.…”

Structural Integrity Assessment of Composites Plates with Embedded PZT Transducers for Structural Health Monitoring

“…Currently, composite materials are widely used in the manufacturing of airframes due to their high mechanical performance with lower densities and high resistance to fatigue and corrosion [1][2][3][4][5]. However, they can suffer from unforeseen impact events during their operation and maintenance, which may result in barely visible damages.…”

“…Structural health monitoring (SHM) is a promising nondestructive inspection technique which offers a realtime damage detection under operational and environmental conditions for aircrafts [6][7][8][9]. There are many different types of sensors that can be used in SHM, such as strain gauges [4], optical fibres (OF) [10], carbon nanotube (CNT) sensing networks [11], and piezoelectric lead zirconate titanate (PZT) transducers [12]. These sensors are normally installed on the surface of composites but can also be embedded inside the host structure.…”

“…For strain gauges, Belhouideg et al [4] conducted mechanical tests (tensile, threepoint bending, fatigue tests) when embedding strain gauge into glass fibre reinforced epoxy composites for SHM techniques. They demonstrated that reductions of tensile tests with embedded strain gauges for the tensile stiffness and tensile strength were 5.8% and 1.5%, respectively.…”