Structural health monitoring

About: Structural health monitoring is a research topic. Over the lifetime, 11727 publications have been published within this topic receiving 186231 citations.

Smart sensing skin for detection and localization of fatigue cracks

Abstract: Fatigue cracks on steel components may have strong consequences on the structure’s serviceability and strength. Their detection and localization is a difficult task. Existing technologies enabling structural health monitoring have a complex link signal-to-damage or have economic barriers impeding large-scale deployment. A solution is to develop sensing methods that are inexpensive, scalable, with signals that can directly relate to damage. The authors have recently proposed a smart sensing skin for structural health monitoring applications to mesosystems. The sensor is a thin film soft elastomeric capacitor (SEC) that transduces strain into a measurable change in capacitance. Arranged in a network configuration, the SEC would have the capacity to detect and localize damage by detecting local deformation over a global surface, analogous to biological skin. In this paper, the performance of the SEC at detecting and localizing fatigue cracks in steel structures is investigated. Fatigue cracks are induced in steel specimens equipped with SECs, and data measured continuously. Test results show that the fatigue crack can be detected at an early stage. The smallest detectable crack length and width are 27.2 and 0.254 mm, respectively, and the average detectable crack length and width are 29.8 and 0.432 mm, respectively. Results also show that, when used in a network configuration, only the sensor located over the formed fatigue crack detect the damage, thus validating the capacity of the SEC at damage localization.

Wavelet-based vibration sensor data compression technique for civil infrastructure condition monitoring

Abstract: Civil infrastructure condition monitoring generates large volumes of sensor data. Huge data size impedes fast and reliable distribution of sensor data, especially for wireless sensor networks. Vibration sensor data plays an important role in many useful structural health monitoring methods. This paper presents a vibration sensor data compression technique based on the lifting scheme wavelet transform (LSWT). Real sensor data from a nine-story building as well as a steel truss bridge was used to examine the compression performance of the LSWT-based vibration sensor data compression technique. It is found that the LSWT-based vibration sensor data compression technique can achieve a very high compression ratio while retaining the basic waveform properties of original sensor data. Additionally, LSWT has a feature that supports progressive compression and thus allows for multiresolution data transmission and retrieval.

Electromechanical Impedance-Based Structural Health Monitoring with Evolutionary Programming

Abstract: An impedance-based structural health monitoring technique is presented. By analyzing the in-plane vibration of a thin lead–zirconate–titanate (PZT) patch, the electromechanical impedance of the PZT patch is predicted. The force impedances of a beam and a plate with damage are calculated by Ritz method using polynomial as shape functions. The damage is then identified from the changes of the impedance spectra caused by the appearance of damage. A hybrid evolutionary programming is employed as a global search technique to back-calculate the damage. A specially designed fitness function is proposed, which is able to effectively reduce the inaccuracy in representing the real structure using analytical or numerical models. Experiments are carried out on a beam and a plate to verify the numerical predictions. The results demonstrate that the proposed method is able to effectively and reliably locate and quantify the damage in the beam and the plate.

Multiscale Modeling and Model Updating of a Cable-Stayed Bridge. I: Modeling and Influence Line Analysis

Abstract: Structural health monitoring (SHM) systems have been installed in many long-span bridges to assess bridge performance and safety. However, the number of sensors in a SHM system is always limited; therefore, not all of the bridge components can be directly monitored. To facilitate an effective assessment of stress-related bridge performance and safety, a multiscale finite-element (FE) model with detailed geometry and affordable computation time is needed. This paper presents the details of establishing a multiscale model for the Stonecutters Bridge in Hong Kong, which is a cable-stayed bridge with a 1,018-m main span. The twin-box deck of the bridge is modeled with shell elements in detailed geometry such that all stress responses in the bridge deck can be directly computed; other bridge components are modeled using either beam or truss elements. Each segment of the girder is then condensed into a superelement with the substructuring method in order to reduce the number of degrees of freedom. A se...