Structural Health Monitoring Methods
Traditional non-destructive testing methods such as ultrasonic, X-Ray have been used for many years for the detection of damages in composite materials. However, these methods are difficult to use due to complex materials, intensive and long labor, high costs and damage detection in certain areas. In addition, maintenance costs are high due to the materials and equipment used (Cai et al., 2012).
In the classical SHM method, different types of sensors are integrated into the structures to detect changes such as strain, temperature, vibration, and stress. For this, resistance change sensors, fiber optic sensors, piezoelectric sensors, eddy current sensors and microelectromechanical system (MEMS) sensors are used. The use of the classical SHM methods in composite materials is by active and passive ways, depending on the use of actuators (Cuc et al., 2007). In passive SHM, it is formed as a result of processing and interpreting the signals obtained by simply listening to the irregularities caused by various situations without any intervention (Figure 1- a). In the active SHM method, the data is created by the actuators and obtained as a result of the interpretation of the data by means of sensors (Figures 1-b).
With the SHM method, accurate and reliable damage determination of the whole material can be made instantly and cheaper with the right designs. In the following, it has been investigated that the electrical conductivity of an insulating material by adding nanoparticles to glass fiber reinforced epoxy matrix materials and the damage progression of an insulating material by SHM method, in the whole part, with instant data. The electrical resistance changes of the network formed as a result of the addition of different types of nanoparticles (such as carbon nanotube, graphene, carbon black) into the epoxy matrix was investigated by structural health monitoring.