scholarly journals Damage Detection in Fiber-Reinforced Foamed Urethane Composite Railway Bearers Using Acoustic Emissions

2020 ◽  
Vol 5 (6) ◽  
pp. 50 ◽  
Author(s):  
Pasakorn Sengsri ◽  
Chayut Ngamkhanong ◽  
Andre Luis Oliveira de Melo ◽  
Mayorkinos Papaelias ◽  
Sakdirat Kaewunruen

To a certain degree, composite railway sleepers and bearers have been recently employed as a replacement for conventional timber sleepers. Importantly, attributed to the rise in traffic demand, structural health monitoring of track structural members is essential to improve the maintenance regime and reduce risks imposed by any structural damage. A potential modern technique for detecting damage in railway components by using energy waves is called acoustic emission (AE). This technique has been widely used for concrete structures in other engineering applications, but the application for composites is relatively limited. Recently, fiber-reinforced foamed urethane (FFU) composites have been utilized as railway sleepers and bearers for applications in the railway industry. Neither does a design standard exist, nor have the inspection and monitoring criteria been properly established. In this study, three-point bending tests were performed together with using the AE method to detect crack growth in FFU composite beams. The ultimate state behaviors are considered to obtain the failure modes. This paper is thus the world’s first to focus on damage detection approaches for FFU composite beams using AE technology, additionally identifying the load-deflection curves of the beams. According to the experimental results, it is apparent that the failure modes of FFU composite beams are likely to be in brittle modes. Through finite element method, the results were in good agreement with less than 0.14% discrepancy between the experimental and numerical data. The attractive insights into an alternative technique for damage assessment of the composite components will help railway engineers to establish structural monitoring guidelines for railway composite sleepers and bearers.

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
U. Baneen ◽  
J. E. Guivant

This paper presents a method for the detection of damage present in composite beam-type structures. The method, which successfully detected damage in steel beams, is applied to a glass fiber-reinforced beam in order to verify its suitability for composite structures as well. The damage indices were obtained using the gapped-smoothing method (GSM), which does not require a baseline model in order to detect damage. Despite the advantage of avoiding the need for a reference model altogether, unavoidable measurement errors make GSM rather ineffective. The proposed method uses the damage indices that GSM provides for synthesizing a set of likelihood functions that is processed under a Bayesian approach in order to reduce the effect of the noise and other uncertainty sources. The quality of the damage detection was examined by investigating an optimal sampling size analytically, and it was demonstrated through numerical simulation. This paper details the theory of the noise suppression method based on Bayesian data fusion, includes an analysis of the optimal sampling size, and presents the experimental results for two glass fiber-reinforced composite beams with a narrow and wide delamination, respectively. A noise-addition process was applied to the simulated data considering two different noise distributions. The composite beam was modeled in ANSYS, and harmonic analysis was used to obtain the frequency response functions at different beam locations. The results were obtained by adding 5, 10, and 15% noise in the simulated data, and they were then validated from the experimental results.


2006 ◽  
Vol 111 ◽  
pp. 63-66 ◽  
Author(s):  
K. Mohan ◽  
Tick Hon Yip ◽  
Idapalapati Sridhar ◽  
H.P. Seow

Aluminum foams are very popular material for structural applications because of its attractive combination of properties. Structural performance of those foams can be enhanced by bonding them between strong and stiff face sheets such as carbon fiber reinforced plastics (CFRP). The response of hybrid sandwich panels comprising aluminum foam core and CFRP face sheets were investigated under three-point bending and measured response is verified with finite element numerical simulations. Core indentation and core shear, failure modes are identified. Experimentally measured elastic stiffness and failure load of thee tested beams were found to be in good agreement with the numerical simulation and analytical predictions.


2018 ◽  
Vol 1148 ◽  
pp. 43-47 ◽  
Author(s):  
Vemu Vara Prasad ◽  
Javisseti Nageswara Rao

Among various composites available for use, carbon fiber reinforced composite is unique in its Nature. Carbon fiber is an extremely strong thin fiber made by pyrolyzing synthetic fibers, such as rayon, until charred. High Strength Composites are made from this fiber by using appropriate matrix material mostly Epoxy resins are used. High Strength, stiffness, light weight and high thermal conductivity are the main advantages over the other composites. Making products with one single composite sheet is not possible always. Some of the intricate or complex shape making is required for joining of two composite sheet. The composites joining can be done in three ways mainly Adhesive, Riveting and Hybrid. Based on the Review among all these joints adhesive joining gives better economic solution in joining. Experimental results point to significant influence of fibre on mechanical properties of sample. The tensile test of the acoustic signal emission (AE) to identify the current state of material integrity in real time. Acoustic system signal correlated to damage events. The carbon fiber composite characteristic failure mechanisms are initiated on the microscale and result in a spontaneous release of elastic energy in terms of mechanical stress waves, the so-called acoustic emissions.


Sensors ◽  
2019 ◽  
Vol 19 (12) ◽  
pp. 2799
Author(s):  
Fengjiang Qin ◽  
Zhigang Zhang ◽  
Bo Xie ◽  
Rui Sun

The use of engineered cementitious composite (ECC) has attracted extensive attention in recent years because of the highly enhanced ductility owing to its unique strain-hardening behavior. In this paper, an electromechanical impedance-based technique is used to monitor the structural damage of RC beams strengthened with an ECC layer at the tensile zone. To achieve this purpose, three specimens are tested under bending loads to evaluate the proposed damage detection methodology. Five externally bonded PZT transducers are uniformly distributed at the surface of the ECC layer of the beams to measure the output conductance signatures in a healthy state and in different damage scenarios induced by different load levels. Test results showed that discrepancies exist between the signals measured in the intact state and each damage state, which can be used to evaluate the structural integrity changes. To assess the damage of ECC-concrete composite beams quantitatively, the statistical scalar index-root mean square deviation (RMSD) is used as the index, which can be calculated from the variations of conductance measurements of PZT sensors. The damage index values of the uniformly distributed PZT sensors provided cogent evidence of damage and revealed the evolution of structural damage. The crack patterns of beams at different damage levels are compared with the damage index values, and it shows the damage location can be derived from the measured conductance signatures of an array of PZT transducers.


Author(s):  
Xudong Yang ◽  
Lingyu Sun ◽  
Lijun Li ◽  
Cheng Zhang

Assembly Fiber-Reinforced Thermoplastic Polymer (AFRTP) is a hybrid material manufactured by injection overmolding of short/long fiber-reinforced thermoplastic resin on the back of continuous fiber-reinforced laminate preformed by thermal stamping to achieve both high mechanical properties and complex geometries. This new technique has attracted large attention from industry recently. The difficulty in applying AFRTP is the progressive damage prediction of heterogeneous interface because the difference in mechanical properties result from materials and process may lead to the interface separation when subjected to bending or tension loads that reduce the bending resistance capability of AFRTP plates. In this paper, the interfacial cohesive parameters of AFRTP structure are identified based on the published experimental data. Additionally, the low-speed impact under three-point bending loads is simulated and the interface stress distribution and failure modes reveal the damage mechanisms of AFRTP interface under shear stress.


2013 ◽  
Vol 831 ◽  
pp. 53-57
Author(s):  
Run Hua Xiao ◽  
Jian Chun Li ◽  
Ri Jun Shrestha

In recent years, research trend on structural condition assessments have largely shifted toward utilizing vibration based methods for structural damage detection and evaluation. On the other hand, research and applications on use of fiber reinforce polymer (FRP) on timber for strengthening or repair damaged timber members in various types of timber structures has also become increasingly popular. Although the application of FRP for repair and/or strengthening of structures has been researched for a long time, research on non-destructive assessment or evaluation of the effectiveness and reliability after FRP repairing or strengthening is yet to be carried out. In this paper, the authors made an attempt on investigation of such issue utilizing Damage Index method, which is a robust vibration-based approach for damage detection. The investigation was aiming at localizing and quantifying damage in timber beams and, more importantly evaluating the effectiveness after the damage was repaired. An experimental program was carried out on five laminated veneer lumber (LVL) beams. Various damage scenarios (i.e. severe, medium, light damage) are introduced on these beams and then repaired with carbon fiber reinforced polymer (CFRP). Experimental results indicate that the use of CFRP was effective in repairing the damaged timber beams. Utilizing Damage Index method can accurately detect the damage location. However, the investigation also shows that direct application of the Damage Index for evaluation of the effectiveness of rehabilitation of the damaged timber beam is not satisfactory. Further investigation and modification of the Damage Index method will be carried out in next stage research.


2019 ◽  
Vol 23 (1) ◽  
pp. 277-286
Author(s):  
Dominik Banat

Abstract The subject of this article is the finite element method (FEM) simulation of the multi-layered rectangular composite beam subjected to three-point bending test. The study is focused on the composite beams made of glass or carbon fibre-reinforced laminates (glass fibre-reinforced polymer [GFRP] and carbon fibre-reinforced polymer [CFRP]) for which different laminate stacking were addressed. Three beam geometries with various length-to-thickness ratios included short beam shear (SBS) test, provided the beam is short relative to its thickness, which maximised the induced shear stresses. Simulation included the application of Tsai–Hill, Hoffman, Tsai–Wu, Hashin and Puck failure criteria to perform the composite beam failure analysis wherein the matrix and fibre failure were considered separately. Numerical failure studies also aimed to verify the beam failure modes and the participation of stress tensor elements in material failure.


2017 ◽  
Vol 2017 (9) ◽  
pp. 5-16
Author(s):  
Andrzej Katunin ◽  
Michał Zuba

AbstractDamage detection and identification is one of the most important tasks of proper operation of technical objects and structures. It is, therefore, essential to develop efficient and sensitive methods of early damage detection. Delamination is the type of damage occurring in laminated composites that is one of the most dangerous and most difficult to detect. In this paper, the computational study was performed on the numerical data of the modal shapes of laminated composite beams with simulated delaminations in order to detect them using a fractal dimension-based approach. The obtained results allowed for improvement of detection accuracy as compared to previously applied wavelet-based approach. An additional benefit was decreasing the computational time. Basing on the obtained results it is reasonable to consider the presented approach as a promising alternative to currently applied signal processing methods used for supporting non-destructive testing of structures.


2019 ◽  
Vol 3 (3) ◽  
pp. 452 ◽  
Author(s):  
Du Dinh-Cong ◽  
Linh Vo-Van ◽  
Dung Nguyen-Quoc ◽  
Trung Nguyen-Thoi

Modal kinetic energy (MKE) feature has been mostly employed for optimal sensor layout strategies; nevertheless, little attention is paid to use the feature to the field of structural damage detection. The article presents the extensive applicability of MKE change ratio (MKECR), a good damage sensitive parameter, to damage localization and quantification of laminated composite beams. The formulation of the parameter is based on the closed-form of element MKE sensitivity. The performance of the offered damage detection method is numerically verified by a clamped-clamped composite beam and a two-span continuous composite beam with different hypothetical damage scenarios. The influence of incomplete mode shapes, various noise levels as well as damage magnitudes on damage prediction results are also investigated. The obtained results from these numerical examples indicate that the offered method reliably localize the actually damaged elements and approximately estimate their severities, even under incomplete measurements at a high noise level.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium provided the original work is properly cited. 


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