Journal articles: 'Damage Indicators'

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Nanda, Bharadwaj, Aditi Majumdar, Damodar Maity, and Dipak K. Maiti. "Performance Comparison among Vibration Based Indicators in Damage Identification of Structures." Applied Mechanics and Materials 592-594 (July 2014): 2081–85. http://dx.doi.org/10.4028/www.scientific.net/amm.592-594.2081.

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A simple and robust methodology is presented to identify damages in a structure using changes in vibration data. A comparison is made among damage indicators such as natural frequencies, mode shape data, curvature damage factors and flexibility matrices to study their efficacy in damage assessment. Continuous ant colony optimization (ACOR) technique is used to solve the inverse problem related to damage identification. The outcome of the simulated results demonstrates that the flexibility matrix as a damage indicator provides better damage identification.

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Hu, Chuan Shuang, Wei Wen, and Hong Yun. "Damage Detection of Wood Beams Using the Modal Flexibility Curvatures." Advanced Materials Research 538-541 (June 2012): 1815–20. http://dx.doi.org/10.4028/www.scientific.net/amr.538-541.1815.

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Local damages such as knots, decay, and cracks can be translated into a reduction of service life due to mechanical and environmental loadings. In wood construction, it is very important to evaluate the weakest location and detect damage at the earliest possible stage to avoid the future catastrophic failure. In this study, modal testing was conducted on wood beams to generate the first two mode shapes. A novel statistical algorithm was proposed to extract the damage indicator by computing the modal flexibility curvature before and after damage in timbers. Different damage severities, damage locations, and double damages were simulated by removing mass from intact beams to verify the algorithm. The results have shown that the proposed statistical algorithm is effective and suitable to the designed damage scenarios. The proposed algorithm can qualitatively identify the damage existence and its location although there is no linear correlation between damage indicators and damage severities. The peak values of the damage indicators increase when the losses of the second axial moment of area increases. It is also reliable to detect multiple damages.

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Weiss, Volker, and Anindya Ghoshal. "On the search for optimal damage precursors." Structural Health Monitoring 13, no. 6 (November 2014): 601–8. http://dx.doi.org/10.1177/0725513614554732.

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A new approach to predict the service life of critical components via study of damage precursors is emerging and is the topic of this article. To date, most service life predictions are based on measurements of damage indicators and their growth toward criticality or failure, for example, fatigue crack length and material loss due to corrosion or wear. This makes lifetime estimates based on measurements of damage, for example, around half-life, or even at 80% life, difficult and inaccurate. To improve the accuracy and reliability of lifetime prediction, efforts are now underway to determine the state awareness of a critical component during service, based on property characterizations, in addition to the measurements of the direct damage indicators, such as crack length, acoustic emission, ultrasound signals, and eddy current measurements. These characterizations will include indirect damage indicators, that is, precursors and allied or affiliated damage indicators. For affiliated damage indicators, residual stress relaxation or development, phase changes, electrical property (resistivity, dielectric constant, permeability), and microstructural characterization must be considered. The selection of the optimal combination of direct and indirect damage indicators will be application specific. It is proposed to assess the efficacy of damage indicators on the basis of their Di/Df versus Ni/Nf, that is, damage ratio versus life fraction curves (referred to as damage indicator ratio curves), searching for indicators with damage indicator ratio curves that best meet the needs of the application.

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Müller, W. U., and C. Streffer. "Biological Indicators for Radiation Damage." International Journal of Radiation Biology 59, no. 4 (January 1991): 863–73. http://dx.doi.org/10.1080/09553009114550771.

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Mani, A., M. Tabesh, and M. R. Zolfaghari. "Hydraulic performance of post-earthquake water distribution networks based on head driven simulation method." Water Supply 13, no. 5 (September 1, 2013): 1281–88. http://dx.doi.org/10.2166/ws.2013.141.

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Water distribution networks are one of the most important infrastructures in urban areas. Evaluating their real hydraulic performance after being damaged by earthquake loadings is crucial for future planning. In this study, pipeline damage caused by seismic wave propagation is modelled using relationships obtained from 1994 Northridge earthquake. Damaged network is hydraulically analysed using the head driven simulation method (HDSM). This analysis helps to obtain actual performance of the water distribution network damaged by seismic waves, without the usual need to handle negative nodal pressures generated from demand driven simulation method. Pressure performance indicator and the total leakage of the network are used as indicators to show the hydraulic performance of the system. Comparison of the damages from different seismic scenarios and the hydraulic indicators of the network, illustrate the probable condition of the water distribution network after the earthquake. The proposed methodology is applied on a reservoir zone of the Tehran water distribution network. The results indicate the degree of damage in terms of pipe burst and leak points in this network.

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Khatir, Samir, Magd Abdel Wahab, Samir Tiachacht, Cuong Le Thanh, Roberto Capozucca, Erica Magagnini, and Brahim Benaissa. "Damage identification in steel plate using FRF and inverse analysis." Frattura ed Integrità Strutturale 15, no. 58 (September 25, 2021): 416–33. http://dx.doi.org/10.3221/igf-esis.58.30.

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Metaheuristic algorithms have known vast development in recent years. And their applicability in engineering projects is constantly growing; however, their deferent exploration and exploitation techniques cause the engineering problems to favor some algorithms over others. This paper studies damage identification in steel plates using Frequency Response Function (FRF) damage indicator to detect and localize the healthy and damaged structure. The study is formulated as an inverse analysis, investigating the performance of three new metaheuristic algorithms of Wild Horse Optimizer (WHO), Harris Hawks Optimization (HHO), and Arithmetic Optimization Algorithm (AOA). The objective function is based on measured and calculated FRF damage indicators. The results showed that the case of four damages with different damage severity levels presented a good challenge where the HWO algorithm was shown to have the best performance. Both in convergence speed and CPU time.

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ZHU, XINQUN, and HONG HAO. "DAMAGE DETECTION OF RC SLABS USING NONLINEAR VIBRATION FEATURES." International Journal of Structural Stability and Dynamics 09, no. 04 (December 2009): 687–709. http://dx.doi.org/10.1142/s0219455409003247.

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Studied herein are the signatures of nonlinear vibration characteristics of damaged reinforced concrete structures using the wavelet transform (WT). A two-span RC slab built in 2003 was tested to failure in the laboratory. Vibration measurements were carried out at various stages of structural damage. The vibration frequencies, mode shapes, and damping ratios at each loading stage were extracted and analyzed. It is found that the vibration frequencies are not sensitive to small damages, but are good indicators when damage is severe. The dynamic responses are also analyzed in the time–frequency domain by WT and the skeleton curve is constructed to describe the nonlinear characteristics in the reinforced concrete structures. The results show that the skeleton curves are good indicators of damage in the reinforced concrete structures because they are more sensitive to small damages than vibration frequencies.

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Liu, Wei Feng, Shu Xia Zhang, Wei Liu, and Ling Ling Zhou. "Study of Ecological Environment on Assessment Model of Ecosystem Damage Caused by Oil Spill in Ocean." Advanced Materials Research 908 (March 2014): 392–95. http://dx.doi.org/10.4028/www.scientific.net/amr.908.392.

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An ecosystem damage assessment model is built in the paper based on the features of marine ecosystem service damages caused by oil spill and traits of ecosystem service after restoration. The ecosystem damages caused by oil spill are mainly reflected in the following six services, namely, the fishery resource supply, gas regulation, waste disposal, disaster defense, entertainment and biodiversity conservation as well as the restoration expense of respective damage. The damage degree of oil spill to each service of marine ecosystem differs, and the recovery time and speed of respective service also vary. According to the change of service value after being damaged, the damage amount of each service is expressed as an integral function of original value, damage degree and recovery speed. Based on the natures and features of each assessment indicators, the method of environmental economics which can judge its original value is selected, and the ecological scale which can measure the damage degree and recovery speed is determined. Expense statistics method is adopted to monetize ecological restoration indicators.

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Bao, Rui, Tao Li, Xinyi Zhang, Xiao Fu, Yu Zhao, Mingfang Tang, and Hongbing Deng. "Study on forest ecosystem damage assessment system and management system." Sustainable Forestry 5, no. 2 (November 19, 2022): 50. http://dx.doi.org/10.24294/sf.v5i2.1628.

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Ecological environment damage events will destroy or damage the balance between animal and plant habitats and ecosystems, and even pose a threat to China’s ecological security. However, at present, there are some problems in the identification and evaluation of forest ecosystem damage, such as imperfect evaluation system, insufficient quantitative evaluation methods, imperfect damage compensation management system, and lack of analysis of the overall damage of the interaction between human activities and forest ecosystem. Based on the damaged object, the system involves a total of four first-class indicators, including physical damage, mental damage, economic forest fruit loss, forest by-products loss, processing and manufacturing loss, forest tourism loss, scientific research literature and history loss, soil conservation loss, water conservation loss, wind prevention and sand fixation loss, carbon fixation and oxygen release loss, atmospheric purification loss. There are 14 secondary indicators of emergency treatment fee and investigation and evaluation fee, as well as 22 tertiary indicators, and the value quantification method of each indicator is clarified by using market value method, alternative cost method, shadow engineering method, recovery cost method and other methods. The article also discusses the management system of forest ecosystem damage from the two aspects of forestry technology department and judicial administration department. The purpose is to provide reference for the quantification and standardization of forest ecosystem damage assessment technology and the improvement of management system.

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Lakshmanan, N., B. K. Raghuprasad, K. Muthumani, N. Gopalakrishnan, and D. Basu. "Wavelet analysis and enhanced damage indicators." Smart Structures and Systems 3, no. 1 (January 25, 2007): 23–49. http://dx.doi.org/10.12989/sss.2007.3.1.023.

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Le, Thanh-Cao, Duc-Duy Ho, Chi-Thien Nguyen, and Thanh-Canh Huynh. "Structural Damage Localization in Plates Using Global and Local Modal Strain Energy Method." Advances in Civil Engineering 2022 (May 18, 2022): 1–16. http://dx.doi.org/10.1155/2022/4456439.

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This paper presents an improvement to the modal strain energy (MSE) method for identifying structural damages in plate-type structures. A two-step MSE-based damage localization procedure, including a global step and a local step, is newly proposed to enhance the accuracy of detecting the location of structural damage. Firstly, the global step uses the mode shape data on the whole plate to locate the potentially damaged areas. Then, MSE is applied with a more dense mesh size on these local areas to detect damage in more detail. The proposed procedure’s feasibility is verified by analyzing an aluminum plate with various damaged scenarios. This study uses finite element analysis to acquire the plate's natural frequencies and mode shapes in intact and damaged states. A set of two damage detection capacity indicators are also newly presented to evaluate the precision of the proposed procedure. The diagnostic results demonstrate that the proposed approach uses less modal data than the original MSE method and accurately identifies the damage's locations in the plates with various edge conditions. Moreover, the combination of three first mode shapes and a damage threshold of 40% of the maximum normalized damage index gives the best results of damage localization.

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Behtani, Amar, Samir Tiachacht, Tawfiq Khatir, Samir Khatir, Magd Abdel Wahab, and Brahim Benaissa. "Residual Force Method for damage identification in a laminated composite plate with different boundary conditions." Frattura ed Integrità Strutturale 16, no. 59 (December 22, 2021): 35–48. http://dx.doi.org/10.3221/igf-esis.59.03.

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The strongest point about damage identification based on the dynamic measurements, is the ability perform structural health evaluation globally. Researchers in the last few years payed more attention to damage indicators based on modal analysis using either frequencies, mode shapes, or Frequency Response Functions (FRFs). This paper presents a new application of damage identification in a cross-ply (0°/90°/0°) laminated composite plate based on Force Residual Method (FRM) damage indicator. Considering single and multiple damages with different damage levels. As well as investigating the SSSS and CCCC boundary conditions effect on the estimation accuracy. Moreover, a white Gaussian noise is introduced to test the challenge the technique. The results show that the suggested FRM indicator provides accurate results under different boundary conditions. Favouring the SSSS boundary condition than the CCCC for 3% noise.

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Erduran, Emrah, Frida Kristin Ulla, and Lone Næss. "A Framework for Long-Term Vibration-Based Monitoring of Bridges." Sensors 21, no. 14 (July 11, 2021): 4739. http://dx.doi.org/10.3390/s21144739.

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A new framework for long-term monitoring of bridges is proposed in order to negate (i) the impact of measurement uncertainties on damage detection in vibration-based structural health monitoring and (ii) the low sensitivity of damage indicators to low levels of damage. The framework is developed using three vibration-based damage indicators that have an intuitive physical correlation with damage: modal curvature, modal strain energy and modal flexibility. The article first quantifies the efficacy of these damage indicators when based on two observations, one from the undamaged state and one from the monitored state, in detecting and locating damage for different damage levels that are simulated on an 84-m long railway bridge. A long-term monitoring framework based on a new parameter defined as the frequency of the damage indicator exceeding the threshold value within a population of observations is developed. Impact of several factors including the damage location, damage indicator used in the framework, and the noise level on the success of the developed framework was investigated through numerical analysis. The new parameter, when used together with modal strain energy, was shown to provide a very clear picture of damage initiation and development over time starting from very low damage levels. Furthermore, the location of the simulated damage can be identified successfully at all damage levels and even for very high noise levels using the proposed framework.

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Ga¨nser, H. P., A. G. Atkins, O. Kolednik, F. D. Fischer, and O. Richard. "Upsetting of Cylinders: A Comparison of Two Different Damage Indicators." Journal of Engineering Materials and Technology 123, no. 1 (February 15, 2000): 94–99. http://dx.doi.org/10.1115/1.1286186.

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Two damage indicators for ductile failure, as proposed by Hancock–Mackenzie–Gunawardena and Atkins, are compared with experimental results from literature for the upsetting process of cylindrical specimens. It is shown, for this specific example, that quite similar results can be obtained from highly different damage indicators as long as they allow for the accumulation of damage proportional both to the equivalent strain and to the stress triaxiality; the specific mathematical structure of the indicator seems to be of minor importance. These findings give some guidelines for the practical choice of a damage indicator for the simulation of industrial forming processes, and suggest the use of the void growth based Hancock–Mackenzie–Gunawardena indicator even for a certain class of bulk forming processes. In addition, a slight geometry dependence of the failure lines obtained by the Hancock–Mackenzie–Gunawardena indicator is obtained that has so far neither been reported by experimentalists, nor can it be reproduced in a comparable manner by the Atkins indicator. A surprising correlation is found between these results and those obtained from an entirely different micromechanical analysis proposed recently by one of the authors.

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Cao, Hui, and Tong Liu. "Damage Identification of Beams Based on Improved Element Damage Variable with Reconstructed Modal Rotations." International Journal of Computational Methods 12, no. 04 (August 2015): 1540007. http://dx.doi.org/10.1142/s0219876215400071.

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Damage identification of structures is always attractive to researchers because it plays an important role in the health monitoring in many civil engineering structures. When carrying out a health monitoring, sensors are usually laid on a beam to record acceleration signals, in which the modes of the beam can be extracted to construct indicators for detecting damage of the investigated beam. It should be noted that it is difficult to measure rotational signals of the beam at a position where sensors are laid, thus only the modal translations are available. Although the modal translations can be used to construct indicators without modal rotations and often it is the case, an indicator taking into account modal rotations is suggested in application to resist the effect of noise on the accuracy of measurement. In this paper, modal rotations were reconstructed by modal translations using the principle of static condensation and QR decomposition. Then both modal translations and rotations were used to build an indicator based on element modal strain energy with the help of data fusion theory. The modal translations were extracted from accelerations recorded on a beam using stochastic subspace identification (SSI). Studies were carried out on choosing values of parameters in SSI in order to eliminate the effect of noise as nearly as possible. The simulation given by a FEM model and analyses of accelerations recorded on a reinforced concrete beam show that the proposed damage indicator with the efforts of eliminating noise is able to detect the locations of damage in the investigated beams.

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Zhou, Yun-Lai, and Magd Abdel Wahab. "Cosine based and extended transmissibility damage indicators for structural damage detection." Engineering Structures 141 (June 2017): 175–83. http://dx.doi.org/10.1016/j.engstruct.2017.03.030.

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Park, Sang-Eun, and Yoon Taek Jung. "Detection of Earthquake-Induced Building Damages Using Polarimetric SAR Data." Remote Sensing 12, no. 1 (January 1, 2020): 137. http://dx.doi.org/10.3390/rs12010137.

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Remote sensing, particularly using synthetic aperture radar (SAR) systems, can be an effective tool in detecting and assessing the area and amount of building damages caused by earthquake or tsunami. Several studies have provided experimental evidence for the importance of polarimetric SAR observations in building damage detection and assessment, particularly caused by a tsunami. This study aims to evaluate the practical applicability of the polarimetric SAR observations to building damage caused by the direct ground-shaking of an earthquake. The urban areas heavily damaged by the 2016 Kumamoto earthquake in Japan have been investigated by using the polarimetric PALSAR-2 data acquired in pre- and post-earthquake conditions. Several polarimetric change detection approaches, such as the changes of polarimetric scattering powers, the matrix dissimilarity measures, and changes of the radar scattering mechanisms, were examined. Optimal damage indicators in the presence of significant natural changes, and a novel change detection method by the fuzzy-based fusion of polarimetric damage indicators are proposed. The accuracy analysis results show that the proposed automatic classification method can successfully detect the selected damaged areas with a detection rate of 90.9% and false-alarm rate of 1.3%.

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Zhou, Yun-Lai, Nuno M. M. Maia, Rui P. C. Sampaio, and Magd Abdel Wahab. "Structural damage detection using transmissibility together with hierarchical clustering analysis and similarity measure." Structural Health Monitoring 16, no. 6 (December 15, 2016): 711–31. http://dx.doi.org/10.1177/1475921716680849.

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Maintenance and repairing in actual engineering for long-term used structures, such as pipelines and bridges, make structural damage detection indispensable, as an unanticipated damage may give rise to a disaster, leading to huge economic loss. A new approach for detecting structural damage using transmissibility together with hierarchical clustering and similarity analysis is proposed in this study. Transmissibility is derived from the structural dynamic responses characterizing the structural state. First, for damage detection analysis, hierarchical clustering analysis is adopted to discriminate the damaged scenarios from an unsupervised perspective, taking transmissibility as feature for discriminating damaged patterns from undamaged ones. This is unlike directly predicting the structural damage from the indicators manifestation, as sometimes this can be vague due to the small difference between damaged scenarios and the intact baseline. For comparison reasons, cosine similarity measure and distance measure are also adopted to draw out sensitive indicators, and correspondingly, these indicators will manifest in recognizing damaged patterns from the intact baseline. Finally, for verification purposes, simulated results on a 10-floor structure and experimental tests on a free-free beam are undertaken to check the suitability of the raised approach. The results of both studies are indicative of a good performance in detecting damage that might suggest potential application in actual engineering real life.

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Klyovina, Mariya V. "Comparative analysis of material damage from the occurrence of risky events at industrial enterprises and costs on preventive measures (on the example of the regions of the Volga Federal District)." Vestnik of Samara University. Economics and Management 13, no. 2 (July 20, 2022): 41–50. http://dx.doi.org/10.18287/2542-0461-2022-13-2-41-50.

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The article examines the indicators of material damage from the occurrence of man-made emergencies at industrial enterprises of the Russian Federation, indicators of the costs of preventive measures in the Russian Federation. The forecast of a time series with an oscillatory component of material damage from the occurrence of man-made emergencies at industrial enterprises has been carried out. The probability of occurrence of a risk event at the enterprise is calculated based on data on the number of man-made emergencies and the number of enterprises in the region. To assess the impact of the values of indicators of material damage from the occurrence of man-made emergencies at industrial enterprises, as well as indicators of the costs of preventive measures for each subject of the Volga Federal District on the size of this indicator throughout the Federal District, a regression analysis was carried out. Based on it, a model has been developed for the PFD of the relationship of material damage from the occurrence of man-made emergencies and the costs of preventive measures. As a result of the analysis of the components included in the model, it was revealed that the indicators of the costs of preventive measures for the occurrence of man-made emergencies in the Volga Federal District are most influenced by the indicators of the Republic of Bashkortostan, Tatarstan and the Orenburg region. The indicators of the Republics of Mordovia, Tatarstan, as well as the Nizhny Novgorod and Orenburg regions have the greatest impact on the indicator of material damage from the occurrence of man-made emergencies in the Volga Federal District.

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Xiang, Chang Sheng, Yu Zhou, Sheng Kui Di, Li Xian Wang, and Jian Shu Cheng. "Detection Indicator of Structural Nondestructive Damage Based on Flexibility Curvature Difference Rate." Applied Mechanics and Materials 744-746 (March 2015): 46–52. http://dx.doi.org/10.4028/www.scientific.net/amm.744-746.46.

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Applied to the structural damage identification, Modal Flexibility is better than the Modal Frequency and Modal Displacement, the indicators of Flexibility Curvature are effective and sensitive. This paper proposes a new detection indicator which is Flexibility Curvature Difference Rate (FCDR) that by using the change rate of diagonal elements of flexibility curvature difference when before and after damage. The numerical examples of a simple beam, a continuous beam and a frame with the damage conditions of the different positions and different degrees are used to verify FCDR. The result shows that FCDR can well identify the numerical examples damages, and sensitively diagnose the damage near the supports of beam and the nodes of framework.

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Ahmadian, H., J. E. Mottershead, and M. I. Friswell. "Damage location indicators from substructure mode shapes." Inverse Problems in Engineering 8, no. 4 (August 2000): 309–23. http://dx.doi.org/10.1080/174159700088027733.

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Lofrano, E., A. Paolone, G. Ruta, and A. Taglioni. "Perturbation damage indicators based on complex modes." Procedia Engineering 199 (2017): 1949–54. http://dx.doi.org/10.1016/j.proeng.2017.09.297.

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Duvnjak, Ivan, Domagoj Damjanović, Marko Bartolac, and Ana Skender. "Mode Shape-Based Damage Detection Method (MSDI): Experimental Validation." Applied Sciences 11, no. 10 (May 18, 2021): 4589. http://dx.doi.org/10.3390/app11104589.

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The main principle of vibration-based damage detection in structures is to interpret the changes in dynamic properties of the structure as indicators of damage. In this study, the mode shape damage index (MSDI) method was used to identify discrete damages in plate-like structures. This damage index is based on the difference between modified modal displacements in the undamaged and damaged state of the structure. In order to assess the advantages and limitations of the proposed algorithm, we performed experimental modal analysis on a reinforced concrete (RC) plate under 10 different damage cases. The MSDI values were calculated through considering single and/or multiple damage locations, different levels of damage, and boundary conditions. The experimental results confirmed that the MSDI method can be used to detect the existence of damage, identify single and/or multiple damage locations, and estimate damage severity in the case of single discrete damage.

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Brandon, J. A., A. E. Stephens, E. M. O. Lopes, and A. S. K. Kwan. "Spectral indicators in structural damage identification: A case study." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 213, no. 4 (April 1, 1999): 411–15. http://dx.doi.org/10.1243/0954406991522365.

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A pre-loaded cracked cantilever beam was excited vising a random vibration signal. Excitation levels were within the range of amplitudes that caused no suspicion of non-linear behaviour in an undamaged specimen of identical dimensions and material. Spectral signatures were acquired which made it possible to discriminate between open crack, closed crack and breathing conditions. Systematic effects relating to variations in resonant frequency were largely consistent with the literature for a lightly damaged beam but were unsupported for a beam with more severe damage.

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Krysztofik, Józef. "Evaluation of Damage Degree of Inconel 718 using Nondestructive Indicators of Damage." Fatigue of Aircraft Structures 2016, no. 8 (June 1, 2016): 55–64. http://dx.doi.org/10.1515/fas-2016-0003.

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Abstract This paper presents the results of the quantitative evaluation of the degree of damage caused by plastic strain accumulated in static tensile tests and creep tests. To detect changes in the structure of the material and in order to determine the degradation of the materials, nondestructive methods were used, namely the ultrasonic and eddy current methods. In ultrasonic testing, attenuation and acoustic birefringence were used as damage indicators. In the case of the eddy current method, changes in the phase angle of impedance were observed in the material. The material tested was Inconel 718 alloy. Inconel alloys are often find application in extreme working conditions including in the power engineering industry, aviation and aerospace. A new type of specimen with the variable cross-sectional area of the measuring part was used in the tests. This allowed researchers to obtain a continuous distribution of plastic strain and enabled analysis of the material with respect to different damage degrees. The correlation between the degree of damage, expressed by the measure of deformation, and the value of nondestructive indicators was determined. On the basis of it, the dependence indicating the ability to nondestructive evaluation of the degradation degree of the material, subjected to loads exceeding the yield limit was obtained.

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Zhao, Mingjie, Guoyin Wu, and Kui Wang. "Comparative Analysis of Dynamic Response of Damaged Wharf Frame Structure under the Combined Action of Ship Collision Load and Other Static Loads." Buildings 12, no. 8 (July 30, 2022): 1131. http://dx.doi.org/10.3390/buildings12081131.

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In the long-term service, the wharf structure can be damaged by ship impact, wave load, and even earthquake, which will affect the safe production and smooth operation of the port. Based on the theory of structural dynamic response analysis and wavelet packet analysis principle, this paper established the damage identification index of the wharf frame structure. Combining with the finite element method and the dynamic response theory of the wharf frame structure, it set up a finite element analysis model of the dynamic response of the wharf frame structure under the action of multiple loads, with the impact load of the ship as the dynamic load under the non-damaged state and the different damaged states. In addition, the characteristic response point location was drawn up. Furthermore, the transient dynamic analysis and damage index analysis of the frame structure in the non-damaged and damaged state were conducted respectively. In addition, the model test and numerical simulation results were combined to compare and analyze the identification of damage indicators, so as to verify the identification effect of the established damage identification indicators on the structural damage, which lays a foundation for the next step of structural damage identification.

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Kecik, Krzysztof, Krzysztof Ciecielag, and Kazimierz Zaleski. "Damage detection by recurrence and entropy methods on the basis of time series measured during composite milling." International Journal of Advanced Manufacturing Technology 111, no. 1-2 (September 30, 2020): 549–63. http://dx.doi.org/10.1007/s00170-020-06036-9.

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Abstract This paper presents methods for damage detection in machined material on the basis of time series measured during milling of glass-fiber–reinforced polymer (GFRP). Recurrence methods and different types of entropy have emerged as useful tools for detecting subtle non-stationarities and/or changes in nonlinear signals. In this research, a recurrence plot, recurrence quantifications, an approximate entropy, and sample entropy are used. By identifying changes in the cutting force measured during the composite milling process, the damage occurrence has been detected. Firstly, the damage has been modelled as the intentionally introduced hole with different diameters and depths in order to estimate the size detectable damages and to select proper recurrence measures as damage indicators. Next, the experiments with the real damage have been performed and the damage indicators have used.

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Clarkson, P. M., W. C. Byrnes, J. S. White, L. P. Turcotte, and K. M. McCormick. "MUSCLE DAMAGE INDICATORS AFTER TWO ECCENTRIC EXERCISE BOUTS." Medicine & Science in Sports & Exercise 18, supplement (April 1986): S42. http://dx.doi.org/10.1249/00005768-198604001-00207.

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WANG, Z., F. T. K. AU, and Y. S. CHENG. "STATISTICAL DAMAGE DETECTION BASED ON FREQUENCIES OF SENSITIVITY-ENHANCED STRUCTURES." International Journal of Structural Stability and Dynamics 08, no. 02 (June 2008): 231–55. http://dx.doi.org/10.1142/s0219455408002636.

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A statistical method using frequencies of structures under control is proposed for detecting damage. In the study, feedback control based on independent modal space control is first used to assign the pole of the system under detection intentionally. Then the prescribed characteristic frequencies of the structure under control, which may be more sensitive to damage, are obtained and further employed to constitute a sensitivity-enhanced damage indicator (SEDI). The principle of sensitivity-enhancing feedback control for damage detection of multi-degree-of-freedom systems is elaborated. To overcome the effect of measurement noise on modal frequencies, a hypothesis test involving the t-test that utilizes the SEDI is employed to estimate the occurrence of damage, while a statistical pattern recognition method that uses the feature vectors including the SEDI is employed to locate damage. Based on the perturbation theory, the feature vectors are normalized in order to eliminate the effect of damage extent on damage localization. The proposed method is verified by examples including a three-span continuous beam with a single damaged element and the IASC-ASCE benchmark structure with a single damaged brace. Simulation results show that, by using the frequencies of the structures under control, the proposed damage indicators are more sensitive to damage and are capable of detecting and locating small damage of structures.

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Lei, Jiayan, Yiguan Cui, and Wei Shi. "Structural damage identification method based on vibration statistical indicators and support vector machine." Advances in Structural Engineering 25, no. 6 (March 6, 2022): 1310–22. http://dx.doi.org/10.1177/13694332221073983.

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This study presents a support vector machine (SVM) based structural damage detection approach for a steel frame model. Totally 10 structural scenarios including one undamaged and nine damaged cases (D1–D9) are defined by replacing different column elements to reduce the lateral stiffness between layers. Sensors are laid out at each layer of the frame structure to pick up acceleration response stirred up by the simulated white noise excitations. Statistical analysis is carried out and three damage indictor features are extracted from 800 samples of record duration. Subsequently, the SVM classifiers are developed to conduct a series of indictor fusion schemes to identify multiple damage states. The results indicate that the approach has good identification performance with damage features from three indicators, especially for a high dimensional input eigenvector. Meanwhile, acceptable detection accuracy can be obtained in situations with incomplete measurement; the robustness in terms of the resistance against noise is also discussed.

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Song, Young Seok, and Moo Jong Park. "Development of Damage Prediction Formula for Natural Disasters Considering Economic Indicators." Sustainability 11, no. 3 (February 7, 2019): 868. http://dx.doi.org/10.3390/su11030868.

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Damage caused by natural disasters produces the difference of damage size not only according to damage volume or size, but a national economic level. In addition, budgets and aids should be constantly acquired for disaster management since natural disasters sporadically or irregularly occur. This study proposed disaster management methods by countries considering natural disaster damage documents and economic indicators from 1900 to 2017 among 187 countries in the world. It developed a damage prediction formula considering damage documents of previous natural disasters, economic indicators by countries, and basic indicators as disaster management methods by countries. Independent variables of the damage prediction formula include GDP, population, and area. It applied multiple regression analysis and calculated average human losses due to death, human losses affected, and damage costs by countries. Regarding the adjusted R² of the natural disaster damage prediction formula, the human losses from deaths mean was 0.893, the human losses affected mean was 0.915, and the damage costs mean was 0.946, which had higher explanatory powers. Therefore, results from this study are considered to calculate quantitative damage sizes considering uncertain damage sizes of natural disasters, economic indicators by countries, and are used as indicators for disaster management.

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Ngo, Han-Cuong, Tuan Minh Ha, Saiji Fukada, and Duc-Duy Ho. "Study on detecting deterioration in beam structure stiffness using deformed shape." IOP Conference Series: Materials Science and Engineering 1289, no. 1 (August 1, 2023): 012038. http://dx.doi.org/10.1088/1757-899x/1289/1/012038.

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Abstract This study presents a diagnostic technique for identifying the loss of stiffness of homogeneous beams using only the deformed shape in an effort to develop more effective building health monitoring instruments. Method based on a correlation between beam deformation at two damaged and undamaged selection states. Diagnostic indicators such as the correlation coefficient (CC) and the absolute value of the mean deviation ratio (MAPD) are extensively used to determine the presence of decreased stiffness. Using an approach based on finite element analysis, the deformation line data is computed. Various failure scenarios are proposed to evaluate the beam damage detection sensitivity of the indicators. In the case of beam damage, the CC index value is less than 1, and in the absence of damage, it is equal to 1. Similarly, for the MAPD index, the value is greater than 0 in the case of damage to the beam and 0 in the case of no assumed failure. The result demonstrates that the deformed line data can be used to calculate the assessment indicators for determining the onset of damage in homogeneous beams. Indicators that have not yet determined the location of the local stiffness decline on the beam when using input data are the deformed shape corresponding to the survey examples in this study.

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Indutnyi, Volodymyr, Nina Merezhko, and Kateryna Pirkovich. "Assessment of damage to national and world cultural heritage due to damage or destruction of archaeological monuments." InterConf, no. 34(159) (June 20, 2023): 80–95. http://dx.doi.org/10.51582/interconf.19-20.06.2023.008.

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A methodology for practical assessment of the level of financial losses of world and national cultures caused by the damage or destruction of archaeological monuments is presented. It is based on author's algorithms for the analysis of the state of the market of cultural values and the calculation of the "evaluation base", as well as the indicator of the level of the average annual expenditure of citizens to meet their own humanitarian needs. An example of the evaluation of a unique monument of archeology and a table of value indicators are provided, which greatly simplifies the work of professional appraisers.

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Cheng, Yin, Hongmei Lu, Yani Qian, Quanfeng Li, Bing He, and Chengnong Guan. "Monitoring Simulation of Athlete Dynamic Injury Based on NoSQL Database and Localization Algorithm." Mobile Information Systems 2022 (October 11, 2022): 1–10. http://dx.doi.org/10.1155/2022/1518258.

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This article analyzes NoSQL databases, including three NoSQL data models, and analyzes the principles of two NoSQL representative products, Redis and MongoDB. Secondly, dynamic damage monitoring was introduced into the development of a Redis-based question-and-answer system. After proper improvement, certain noise and reverberation can also have relatively good positioning accuracy, which can be widely used in the system. The identification and classification of damage are based on the corresponding standards of the sports federation’s damage monitoring system. Through expert interviews and investigations, the effectiveness and adequacy of physiological and biochemical indicator monitoring are understood to ensure a better evaluation of athletes’ performance indicators. The method of experimental observation was used to monitor the physical function of athletes. During winter training, indicators were monitored, data were recorded, test conditions were recorded, and dynamic injury monitoring mathematical statistics were used for experimental analysis to objectively evaluate the physiological and biochemical indicators of athletes. This article mainly introduces the NoSQL database and sound source localization to dynamic damage monitoring so as to promote its continuous development.

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Gautier, G., R. Serra, and J. M. Mencik. "Roller Bearing Monitoring by New Subspace-Based Damage Indicator." Shock and Vibration 2015 (2015): 1–11. http://dx.doi.org/10.1155/2015/828093.

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A frequency-band subspace-based damage identification method for fault diagnosis in roller bearings is presented. Subspace-based damage indicators are obtained by filtering the vibration data in the frequency range where damage is likely to occur, that is, around the bearing characteristic frequencies. The proposed method is validated by considering simulated data of a damaged bearing. Also, an experimental case is considered which focuses on collecting the vibration data issued from a run-to-failure test. It is shown that the proposed method can detect bearing defects and, as such, it appears to be an efficient tool for diagnosis purpose.

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Xu, Xiang Feng, Feng Zhang, and Wen Xin Zhu. "Damage Detection of Continuous Box Girder Based on Modal Flexibility Curvature Method." Advanced Materials Research 671-674 (March 2013): 1016–20. http://dx.doi.org/10.4028/www.scientific.net/amr.671-674.1016.

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The modal flexibility was more effective than structural frequency and displacement mode on damage detection of structures, it could be calculated easily based on low order mode of box girder. The damage detection method was proposed based on the modal flexibility curvature in this article, this indicator considered the impact of length difference of adjacent elements on modal flexibility matrix. Damage sensitivities of indicators is contrasted. Calculating results show that flexibility curvature difference has good detection effect on single point damage, multi-point damage and side element damage. The method in this article has good effect on damage detection of box girder.

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Sun, Hong Chun, and Yuan Cheng You. "Overview of the Diagnostic Methods of Engineering Components Damage Based on Modal Analysis." Applied Mechanics and Materials 229-231 (November 2012): 410–14. http://dx.doi.org/10.4028/www.scientific.net/amm.229-231.410.

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This article describes the history of the development of structural damage, and an overview of current research status at home and abroad based on modal analysis of structural damage identification, reviewed in recent years the structure of the early damage recognition technology, from the application point of view of definition of indicators and indicators on the current some indicators of a comprehensive analysis and evaluation, further analysis of the feasibility of several modes of indicators to identify structural damage diagnosis, pointing out that the modal parameters of structural indicators to the validity and accuracy of damage identification and the need to further address the problem. The research will provide a reference for the application of modal analysis method to detect structural damage diagnosis in order to ensure early discovered the damage and accurately identify the site of injury repair in a timely manner.

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Song, Youngseok, Heesup Lee, Jinbok Kim, Jongun Park, and Moojong Park. "Developing Drought Damage Prediction Equation Considering Economic Indicators and Basic Indicators of Asian Countries." Journal of the Korean Society of Hazard Mitigation 19, no. 7 (December 31, 2019): 451–61. http://dx.doi.org/10.9798/kosham.2019.19.7.451.

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Huang and Zang. "Damage Detection Using Modal Rotational Mode Shapes Obtained with a Uniform Rate CSLDV Measurement." Applied Sciences 9, no. 23 (November 20, 2019): 4982. http://dx.doi.org/10.3390/app9234982.

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With the rapid development of a continuously scanning laser Doppler vibrometer (CSLDV) technique, the full-field mode shapes of structures with high accuracy can be obtained. In this paper, a novel damage detection method using modal rotational mode shapes obtained with a uniform rate CSLDV measurement is proposed. The modal rotational damage indicators considering the changes of modal rotational mode shapes between the damaged and the undamaged states are established. Because the modal rotational mode shapes are obtained through the derivative of the detailed displacement mode shapes of transitional degree-of-freedoms (DOFs) with respect to the orthogonal directions, they are more sensitive than the normal displacement mode shapes. The uniform rate CSLDV measurement is essentially a uniform straight-line scanning technique and the measured mode shapes can be directly obtained through the demodulation of vibration signals. Besides, taking it for granted that a priori knowledge of the undamaged structure is not known, the undamaged mode shapes can be reconstructed from the measured damaged data using the fitted polynomial functions in which the minimum number of polynomial function coefficients are determined by a fit value threshold. The proposed method is firstly demonstrated by numerical simulation of the crack plate and then a plate structure with three damaged cases is taken as an example for further experimental study. The experimental results indicate the following: (1) The uniform rate CSLDV measurement can obtain the high accuracy modal rotational mode shapes with the advantage of eliminating the contaminated noise in the measurement; (2) the modal rotational damage indicators of the torsional modes are the most sensitive to the crack damage and they can clearly identify single, multiple damages and locations of the plate, and even slight crack damage, respectively. The effectiveness of the method paves the way for practical applications, such as ultra-light or composite structures.

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Rich, Tina, Livia B. Henderson, David L. Becker, Hannah Cornell, and Janet C. Patterson-Kane. "Indicators of replicative damage in equine tendon fibroblast monolayers." BMC Veterinary Research 9, no. 1 (2013): 180. http://dx.doi.org/10.1186/1746-6148-9-180.

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Heitner, Barbara, Eugene J. OBrien, Franck Schoefs, Thierry Yalamas, Rodrigue Décatoire, and Cathal Leahy. "Probabilistic Modelling of Bridge Safety Based on Damage Indicators." Procedia Engineering 156 (2016): 140–47. http://dx.doi.org/10.1016/j.proeng.2016.08.279.

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Dannecker, Erin A., Ying Liu, R. Scott Rector, Tom R. Thomas, Stephen P. Sayers, Christiaan Leeuwenburgh, and Bimal K. Ray. "The effect of fasting on indicators of muscle damage." Experimental Gerontology 48, no. 10 (October 2013): 1101–6. http://dx.doi.org/10.1016/j.exger.2012.12.006.

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Prasad, B. K. Raghu, N. Lakshmanan, K. Muthumani, and N. Gopalakrishnan. "Enhancement of damage indicators in wavelet and curvature analysis." Sadhana 31, no. 4 (August 2006): 463–86. http://dx.doi.org/10.1007/bf02716787.

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Fischer, F. D., O. Kolednik, G. X. Shan, and F. G. Rammerstorfer. "A note on calibration of ductile failure damage indicators." International Journal of Fracture 73, no. 4 (1995): 345–57. http://dx.doi.org/10.1007/bf00027274.

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AitAmeur, L., M. Zude, G. Trystram, and I. Birlouez-Aragon. "Hydroxymethylfurfural: an indicative parameter of heat damage in cereal products." Czech Journal of Food Sciences 22, SI - Chem. Reactions in Foods V (January 1, 2004): S99—S101. http://dx.doi.org/10.17221/10626-cjfs.

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The main chemical changes occurring during biscuit cooking result from two complex reactions involving reducing sugars: the Maillard reaction and caramelisation, both of them being responsible for non enzymatic browning. These reactions were assessed by determinations of furosine (Fu), hydroxymethylfurfural (HMF), and colour at different times (each 2 min) of the cooking process (10 min). The surface colour of biscuits was carried out with L* a* b* parameters, and the global browning development was measured by the reflectance of the whole biscuit in powder. Simultaneous formation of HMF, Fu and browning were investigated to evaluate the correlation between parameters during cooking and identify the best indicators of the biscuit quality. Fu was almost stable during the first 4 min before decreasing in the last 6 min. In contrast, HMF exponentially increased after 4 min, when the water activity reached 0.6. Reflectance was linearly correlated to cooking time and was well correlated to HMF. We conclude that HMF could be a useful indicator for controlling the cooking process of biscuits.

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Gouda, K., P. Rycerz, A. Kadiric, and GE Morales-Espejel. "Assessing the effectiveness of data-driven time-domain condition indicators in predicting the progression of surface distress under rolling contact." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 233, no. 10 (March 27, 2019): 1523–40. http://dx.doi.org/10.1177/1350650119838896.

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Condition monitoring of machine health via analysis of vibration, acoustic and other signals offers an important tool for reducing the machine downtime and maintenance costs. The key aspect in this process is the ability to relate features derived from the recorded sensor signals to the physical condition of the monitored asset in real time. This paper uses simple machine learning techniques to examine the ability of specific time-domain features obtained from vibration signals to predict the progression of surface distress in lubricated, rolling-sliding contacts, such as those found in rolling bearings and gears. Controlled experiments were performed on a triple-disc rolling contact fatigue rig using seeded-fault roller specimens where micropitting damage was generated and its progression directly observed over millions of contact cycles. Vibration signals were recorded throughout the experiments. Features known as condition indicators were then extracted from the recorded time-domain signals and their evolution related to the observed physical state of the associated specimens using simple machine learning techniques. Five time-domain condition indicators were examined, peak-to-peak, root-mean-square, kurtosis, crest factor and skewness, three of which were found not to be redundant. First, a classification model using KNN nearest neighbor was built with the three informative condition indicators as training data. The cross-validation results indicated that this classifier was able to predict the presence of micropitting damage with a relatively high precision and a low rate of false positives. Secondly, a k-means clustering analysis was performed to measure the significance of each condition indicator by leveraging patterns. The peak-to-peak condition indicator was found to be a good predictor for progression of micropitting damage. In addition, this indicator was able to distinguish between micropitting and pitting failure modes with a high success rate. Finally, the condition indicator response was correlated with the predicted damage state of the test specimen obtained through an existing physics-based surface distress model in order to illustrate the potential of hybrid models for improved prognostics of damage progression in rolling-sliding tribological contacts.

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Payan, C., V. Garnier, and J. Moysan. "Potential of Nonlinear Ultrasonic Indicators for Nondestructive Testing of Concrete." Advances in Civil Engineering 2010 (2010): 1–8. http://dx.doi.org/10.1155/2010/238472.

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In the context of a growing need for safety and reliability in Civil Engineering, acoustic methods of nondestructive testing provide answers to a real industrial need. Linear indicators (wave speed and attenuation) exhibit a limited sensitivity, unlike nonlinear ones which usually have a far greater dynamic range. This paper illustrates the potential of these indicators, and evaluates its potential for in situ applications. Concrete, a structurally heterogeneous and volumetrically, mechanically damaged material, is an example of a class of materials that exhibit strong multiple scattering as well as significant elastic nonlinear response. In the context of stress monitoring in pre-stressed structures, we show that intense scattering can be applied to robustly determine velocity changes at progressively increasing applied stress using coda wave interferometry and thereby extract nonlinear coefficients. In a second part, we demonstrate the high sensitivity of nonlinear parameters to thermal damage as regard with linear ones. Then, the influence of water content and porosity on these indicators is quantified allowing to uncouple the effect of damage from environmental or structural parameters.

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Dzuba A.S., Eleonsky S.I., Pisarev V.S., and Yashutin A.G. "Influence of artificial notch length in composite material on damage indicator values." Technical Physics 68, no. 3 (2023): 345. http://dx.doi.org/10.21883/tp.2023.03.55808.272-22.

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Novel experimental method, which provides visualization of interference fringe patterns caused by inserting of artificial notch of prefixed length in composite material, is developed. Deformation response to local material removing is measured by electronic speckle-pattern interferometry. Interferogram interpretation in terms of in-plane displacement components produces determination of two deformation parameters. These parameters represent current damage indicators, which are essential for quantitative description of damage accumulation inherent in fatigue loading of specimens with stress concentrators. Both damage indicators are derived on a base of direct physical measurements by fringe order counting. Analysis of uncertainties in damage indicators determination, which are connected with incorrect prescribing of artificial notch length, is presented. Keywords: composite materials, speckle-pattern interferometry, artificial notch, damage indicators.

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Carminati, M., and S. Ricci. "Structural Damage Detection Using Nonlinear Vibrations." International Journal of Aerospace Engineering 2018 (September 25, 2018): 1–21. http://dx.doi.org/10.1155/2018/1901362.

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Nonlinear vibrations emerging from damaged structures are suitable indicators for detecting defects. When a crack arises, its behavior could be approximated like a bilinear stiffness. According to this scheme, typical nonlinear phenomena as the presence of superharmonics in the dynamic response and the variation of the oscillation frequency in time emerge. These physical consequences give the opportunity to study damage detection procedures with relevant improvements with respect to the typical strategies based on linear vibrations, such as high sensitivity to small damages, no need for an accurate comparison model, and behavior not influenced by environmental conditions. This paper presents a methodology, which aims at finding suitable nonlinear phenomena for the damage detection of three contact-type damages in a panel representing a typical aeronautical structural component. At first, structural simulations are executed using MSC Nastran models and reduced dynamic models in MATLAB in order to highlight relevant nonlinear behaviors. Then, proper experimental tests are developed in order to look for the nonlinear phenomena identified: presence of superharmonics in the dynamic response and nonlinear behavior of the lower frequency of vibration, computed using the CWT (continuous wavelet transform). The proposed approach exhibits the possibility to detect and localize contact-type damages present in a realistic assembled structure.

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Islam, Hamidul, Muhammed Bhuiyan, Quddus Tushar, Satheeskumar Navaratnam, and Guomin Zhang. "Effect of Star Rating Improvement of Residential Buildings on Life Cycle Environmental Impacts and Costs." Buildings 12, no. 10 (October 4, 2022): 1605. http://dx.doi.org/10.3390/buildings12101605.

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A diagnostic framework is proposed to assess the influence of star rating improvement for residential buildings on life cycle environmental impacts and life cycle costs (LCEI and LCC) using life cycle assessment (LCA) and life cycle costing methods, respectively, on all life cycle phases (i.e., construction, operation, maintenance, and disposal). A reference house was modified on the basis of six alternative designs to deliver a particular star rating in order to demonstrate the analysis framework. Two LCIA methods (i.e., material flows/add masses and eco-indicator 99 Australian substances) were used to estimate ten LCEI indicators under two categories: seven from problem-oriented (i.e., raw material, air emission, water emission, eco-toxicity, acidification/eutrophication potential, ozone depletion, and climate change) and three from damage-oriented (i.e., resource depletion, ecosystem quality, and effect on human health) categories. The three damage-oriented indicators were combined to evaluate environmental and economic wellbeing on a single eco-point basis. All these combinations of impact indicators can offer three lines of analytical options along with star rating: problem-oriented, damage-oriented, and a variety of problem and damage-oriented LCEIs with LCCs. Hence, the optimum house selection is-based not only on cost or star rating, but also on LCEIs.

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Journal articles on the topic 'Damage Indicators'

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