The degradation of steel structure due to corrosion is a common problem found especially in the marine structure due to exposure to the harsh marine environment. In order to ensure safety and reliability of marine structure, the damage assessment is an indispensable prerequisite for plan of remedial action on damaged structure. The main goal of this paper is to discuss simple vibration measurement on plated structure to give image on overview condition of the monitored structure. The changes of vibration response when damage was introduced in the plate structure were investigated. The damage on plate was simulated in finite element method as loss of thickness section. The size of damage and depth of loss of thickness were varied for different damage cases. The plate was excited with lower order of resonance frequency in accordance estimate the average remaining thickness based on displacement response obtain in the dynamic analysis. Significant reduction of natural frequency and increasing amplitude of vibration can be observed in the presence of severe damage. The vibration analysis summarized in this study can serve as benchmark and reference for researcher and design engineer.
This paper presents the overview of aArtificial Neural Network (ANN) in the scope of civil engineering application. ANN is one of the artificial intelligence (AI) applications which are currently one of the effective methods used by engineers and researchers to solve technical problems in many scopes of engineering field. One of the explicit criteria of ANN is the ability of the network to deal with the incomplete data and have the capability of learning from experience. This network is also able to adapt to new and changing situation or environment.
Anticipating the progressive damage and strength of an anisotropic and interbedded rock mass is challenging, due to the overwhelming variables which need to be considered. Therefore, the strength and progressive damage of each rock material is not a realistic model, which can be used to define the deformation of the interbedded anisotropic rock mass. In this research, weathered (sandstone-shale-sandstone) composite samples under unconfined compressive stresses were assessed using acoustic emission (AE) and ultrasonic pulses, concurrently. The deformation behavior was derived following (velocity, amplitude and energy) responses of both the ultrasonic wave, and the AE wave. The optimal reactivity toward progressive deformation was mapped out using the AE intensity energy. Although the ultrasonic velocity was only sensitive toward the macro-deformation or specimen failure, the ultrasonic parameters (i.e., amplitude and energy) reflected a substantial shift, specifically during the micro and macro-deformation. The crack initiation (CI), and the crack damage (CD), which was indicated by the ultrasonic parameters, were addressed as alternative novel approaches for determining the plastic deformation of composite specimens. The CI commenced at 43% - 80%, 53% - 78%, 35% - 55% of the peak stress, whereas the CD occurred at 84% - 97%, 78% - 95%, and 75% - 94% of the peak stress for the weathered sandstone, weathered shale, and composite, respectively. Assuming a significant material strength difference between the interbedded rocks, the current study's findings may assist in the estimation of the deformation behavior of the interbedded rock masses using the ultrasonic technique.
Recently, lightweight composite slabs have become increasingly popular. Lightweight composite slabs are an innovation that provides a better and more convenient construction method for floor systems. Under dynamic loads, lightweight composite slabs may experience meagre inertia forces due to poor stiffness or low mass. Compared to conventional composite slabs, lightweight composite slabs are 40% lighter and more susceptible to structural resonance. Therefore, the vibration behaviour must be controlled to avoid discomfort issues. This study investigates the natural frequency of lightweight composite slabs through experimental study and numerical modelling. In the experimental study, lightweight composite slabs were prepared for the hammer-impact test. The slab thickness ranges from 100 mm to 200 mm. In numerical modelling, lightweight composite slabs were modelled in SAP2000 using a unique technique called the simplified equivalent plate model. The effective material properties were derived from the rule of mixtures and depend exclusively on elastic properties with strength characteristics. The results of the experimental study and numerical modelling agree positively. The natural frequency decreased with slab thickness, signifying that the natural frequency is dominated by mass rather than stiffness. Overall, the natural frequency of lightweight composite slabs is around 27.23Hz to 31.45Hz.
Evaluation methods such as acoustic emission (AE) are required for assessing the deterioration on concrete structures.This paper gives a brief on the evaluations of the acoustic emission to the health monitoring of reinforced concrete structure beam.Small scale size beam have been used for this investigation and the AE signal processing are the main principal data in this work for assessing by using the statistical technique, which is known as intensity analysis method (IA).This technique is capable to quantify and evaluate the damage severity on concrete structures.Eventually, by using the AE signal strength data, the results indicates are greater instruments in determining the damage mechanism level on concretes structure.
Abstract Structural health monitoring (SHM) systems have been developed to evaluate structural responses to extreme events such as natural and man-made hazards. Additionally, the increasing volume of users and vehicle sizes can lead to the sudden damage and collapse of bridge structures. Hence, structural monitoring and dynamic characteristic analyses of bridge structures are critical and fundamental requirements for bridge safety. SHM can overcome the weaknesses of visual inspection practices, such as lack of resolution. However, because of computational limitations and the lack of data analysis methods, substantial quantities of SHM data have been poorly interpreted. In this paper, the SHM of bridges based on dynamic characteristics is used to assess the "health state" of bridge structures. A comprehensive SHM system using vibration-based techniques and modal identification for bridge structures are well defined. Some advanced concepts and applications regarding bridge safety evaluation methods, including damage detection and load-carrying capacity, are reviewed. For the first time, the pros and cons of each vibration technique are comprehensively evaluated, providing an advantage to the authority or structural owner when developing a bridge management database. This information can then be used for continuous structural monitoring to access and predict the bridge structure condition.
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