Effects of high-amplitude low-frequency structural vibrations and machinery sound waves on ultrasonic guided wave propagation for health monitoring of composite aircraft primary structures

A reliable damage diagnostic by ultrasonic guided wave (GW) based structural health monitoring (SHM) can only be achieved if the physical interactions between wave propagation, the SHM system and environmental factors are fully understood. The purpose of this research was to gain knowledge about the effects of high-amplitude low-frequency...

Test results of lateral load insensitive FBGs embedded in composites to suppress spectral distortion

Composite constructions are indispensable in current and future society. Fiber Bragg Gratings (FBGs) embedded in composite need to be carefully aligned with the material fibers to reduce inhomogeneous lateral load exerted onto the FBG which occurs due to the inhomogeneous nature of composite materials. Inhomogeneous load causes distortion of the...

Influence of asphalt on fatigue crack monitoring in steel bridge decks using guided waves

Asphalt materials generally exhibit temperature-dependent properties, which can influence the performance of fatigue crack inspection and monitoring systems for bridge deck structures. For a non-intrusive fatigue crack sizing methodology applied to steel decks using ultrasonic guided waves, the effect of asphalt has been investigated. A higher...

Parametric Nonlinear Regression Models for Dike Monitoring Systems

Dike monitoring is crucial for protection against flooding disasters, an especially important topic in low countries, such as the Netherlands where many regions are below sea level. Recently, there has been growing interest in extending traditional dike monitoring by means of a sensor network. This paper presents a case study of a set of pore...

A new approach for structural health monitoring by applying anomaly detection on strain sensor data

Structural Health Monitoring (SHM) systems help to monitor critical infrastructures (bridges, tunnels, etc.) remotely and provide up-to-date information about their physical condition. In addition, it helps to predict the structure’s life and required maintenance in a cost-efficient way. Typically, inspection data gives insight in the structural...

Special optical fiber design to reduce reflection peak distortion of a FBG embedded in inhomogeneous material

During the last decades, the use of optical fiber for sensing applications has gained increasing acceptance because of its unique properties of being intrinsically safe, unsusceptible to EMI, potentially lightweight and having a large operational temperature range. Among the different Fiber Optic sensor types, Fiber Bragg Grating (FBG) is most...

Time-frequency methods for structural health monitoring

Detection of early warning signals for the imminent failure of large and complex engineered structures is a daunting challenge with many open research questions. In this paper we report on novel ways to perform Structural Health Monitoring (SHM) of flood protection systems (levees, earthen dikes and concrete dams) using sensor data. We present a...

Structural health monitoring for fatigue life prediction of orthotropic bridge decks

Infrastructure asset owners are more and more confronted with structures reaching the end of their structural life. Structural Health Monitoring (SHM) systems should provide up-to-date information about the actual condition, as well predict the structural life and required maintenance of the assets for more cost effective and reliable operation...

Application of SHM using an autonomous sensor network

Assessment of the condition of a structure in operation and subsequently its remaining maintenance free service time, is of increasing importance for various fields of engineering. The main drivers for this are cost effectiveness, increased system reliability, system safety and reduced environmental impact. The current generation of monitoring...

Performance indicator of a bridge expansion joint

In general the condition of a structure can be assessed in terms of a performance indicator. For example, this can be the strength of a structure. An asset manager is concerned with ensuring that the performance of a structure does not fall below a given minimum level. This can be achieved by inspecting or monitoring the structure. As the...

Nanotechnologies, engineered nanomaterials and occupational health and safety - A review

The significance of engineered nanomaterials (ENM) and nanotechnologies grows rapidly. Nanotechnology applications may have a positive marked impact on many aspects of on human every day life, for example by providing means for the production of clean energy and pure drinking water. Hundreds of consumer nano-based products are already on the...

Fiber Bragg Grating sensors for structural health monitoring of Tsing Ma bridge: Background and experimental observation

The rapid expansion of the optical fiber telecommunication industry due to the explosion of the Internet has substantially driven down the cost of optical components, making fiber optic sensors more economically viable. In addition, the rapid development of fiber-optic sensors, particularly the fiber Bragg grating (FBG) sensors offers many...