Structural Engineering Research Centre

About: Structural Engineering Research Centre is a facility organization based out in Chennai, India. It is known for research contribution in the topics: Finite element method & Fracture mechanics. The organization has 520 authors who have published 703 publications receiving 7298 citations.

Studies on Using FBG Sensor as a Tool for Identifying Corrosion in Pipelines

Abstract: Structural health monitoring techniques have captured much interest and attention of researchers owing to their potential in providing spatial and quantitative information regarding structural damage and the performance of a structure. Integrated health monitoring of structures with advances in sensor technology can improve structural reliability, system performance, and safety. Pipelines exist for the transport of crude/refined petroleum, oil, natural gas, and biofuels. These pipelines are made from steel which are usually buried. These pipelines are prone to natural and man-made damages. Hence, monitoring of these buried pipelines becomes essential. Leakages of oil and gas from pipeline are dangerous for people and environment. Detection of leakage along the pipeline network is an essential part of the maintenance activity which is always a difficult task. The experimental studies carried out on using FBG sensors for monitoring corrosion in buried pipelines has been described in this paper. In this study, the FBG sensor is used for measuring the hoop strain variation in the pipeline and from the variation of hoop strain corrosion is identified. Hence, the FBG sensor technology can be adopted for monitoring corrosion in the buried oil and gas pipelines.

Studies on Behaviour of Steel Tubular Compression Members Subjected to Accelerated Corrosion

Abstract: The performance of steel structural components is strongly influenced by the damage due to atmospheric corrosion, whose control is a key aspect for design and maintenance of both new and existing structures. In extreme situations, it can lead to catastrophic failure of structural components. This paper presents experimental and numerical studies on corroded compression members under stressed and unstressed conditions. Experimental studies are carried out on corroded members with different percentage in thickness and weight loss. A methodology has been developed numerically to simulate three types of corrosion cases by using finite element method, namely (1) uniform corrosion, (2) pitting corrosion and (3) uniform and pitting corrosion. The failure modes and the ultimate load carrying capacity of the specimen are determined numerically and validated with experimental results. A significant reduction in load carrying capacity is observed for all corroded specimens compared to uncorroded control specimen. The failure modes and load carrying capacity of corroded members for uniform, pitting and combined effect of uniform and pitting corrosion are discussed. In the light of experimental results, it is inferred that the failure of the members is due to localised axisymmetric imperfections induced in the tubular members due to corrosion.

A Novel Hybrid Technique to Identify the Minor Cracks in the Structure During Online Health Monitoring

Abstract: The basic hypothesis of a structural health monitoring (SHM) system is that the global parameters like stiffness, mass, and damping of a structure are modified by damage and so the dynamic response. Nevertheless, in the case of subtle incipient damage, the changes in the dynamic characteristics of the structures developed in the structure alter only a few modal responses that too in a very mild manner, while all other modal responses remain intact. The damage features present in the modal responses of those few modes will be hidden in the measured total raw dynamic signatures. Often they get buried in the measurement noise. Keeping this in view, in this paper, a hybrid damage diagnostic algorithm combining a multivariate analysis technique called blind source separation (BSS) with time series analysis to identify and locate the minor cracks in structures is proposed. BSS decomposes the measured acceleration time-history responses into modal responses. We use an automated algorithm to isolate the modal responses which are sensitive to the presence of minor/subtle damages. These isolated modal responses are then reconstructed using the mixing matrix to obtain a new time-history data which is enriched with the minor damage features. The presence and spatial location of damage are obtained by processing the reconstructed time-history data using autoregressive–autoregressive with exogenous input (AR-ARX) model, using a Density Function of Probability (PDF), of the prediction errors. Both the numerical simulation studies and experimental studies are carried out to test and evaluate the proposed damage diagnostic algorithm and their capability in identifying minor/incipient damage like subtle cracks under noisy measurements.

Stiffened Rectangular Cantilever Shell Subjected to a Corner Load

Abstract: Stiffened plates and shells find extensive application in the engineering industry. Continuous efforts are being made to devise improved and economical models for predicting their structural behaviour under different types of loads. In view of the complexity of the problem, it is desirable that the performance of theoretical models be checked by comparison with experimental results. It is hard to find in the literature results of experimental investigations on stiffened shells subjected to unsymmetric static lateral loads. This motivated the authors to conduct an experimental investigation on a rectangular cantilever stiffened cylindrical shell subjected to a concentrated load at one of the free corners. This was analysed earlier by Kohnke and Schnobrich. This paper describes the test conducted on a model of a shell using holographic interferometry for obtaining whole-field displacements with high accuracy. After presenting a brief review of the theoretical models used to analyse the shell, the results obtained by experimental and theoretical investigations are discussed.