Artykuły w czasopismach na temat „Damage”
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Vafaei, Mohammadreza, Azlan bin Adnan i Mohammadreza Yadollahi. "Seismic Damage Detection Using Pushover Analysis". Advanced Materials Research 255-260 (maj 2011): 2496–99. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.2496.
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Inter-story drift ratio is a general damage index which is being used to detect damaged stories after severe ground motions. Since this general damage index cannot detect damaged elements also the severity of imposed damages on elements, a new real-time seismic damage detection method base on artificial neural networks was proposed to overcome this issue. This approach considers nonlinear behaviour of structures and not only is capable of detecting damaged elements but also can address the severity of imposed damages. Proposed algorithm was applied on a 3-story concrete building .The obtained results confirmed accuracy and robustness of this method.
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Ma, Hang, Ping Lu, Tao Jiang, Sheng Feng Shi, Jian Bin Wei i Jing Bo Duan. "Research on Feasibility and Applicability of Delamination Localization Methods for Composite Laminated Beams". Applied Mechanics and Materials 599-601 (sierpień 2014): 92–95. http://dx.doi.org/10.4028/www.scientific.net/amm.599-601.92.
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The feasibility and applicability of delamination damages localization methods with various defined damage indexes for the damaged composite laminated beam were studied. The results indicate that, for the modal strain energy method, damage indexes defined by strain energy difference are more effective to locate the delamination damage than that of strain energy ratio. For energy response method, damage index defined by the second difference can effectively locate the delamination damage in the composite laminated beams.
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Gunji, Yukio-Pegio, Tomohiro Shirakawa, Takayuki Niizato, Taichi Haruna i Igor Balaz. "Life Driven by Damaged Damage". Progress of Theoretical Physics Supplement 173 (2008): 26–37. http://dx.doi.org/10.1143/ptps.173.26.
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Liu, Wei Ran, Shou Jun Du i Li Mei Zhang. "Damage Identification of Plane Truss Structure According to Square Difference in Elemental Modal Strain". Applied Mechanics and Materials 724 (styczeń 2015): 22–27. http://dx.doi.org/10.4028/www.scientific.net/amm.724.22.
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A method based on the square difference of elemental modal strain was proposed to determine the damage location and damage degree. The square difference of elemental modal strain was expressed damage before and after. Simulation results show that: this method is effective to locate the single, multiple damages and light, severe damage with low-order modal information. Damage degrees can be initially determined by the values of the square difference of damaged-element modal strain. Furthermore, the result also shows that this method can accurately identify the damage location of plane truss structures with noise.
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Junior, Valdir Mariucci, Luciana Harumi Shigueoka, Carlos Theodoro Motta Pereira, Fernando Cesar Carducci, Tumoru Sera i Gustavo Hiroshi Sera. "Resistance to frost in Arabica coffee lines introgressed with Coffea racemosa Lour. genes". March 2022, nr 16(03):2022 (1.03.2022): 338–42. http://dx.doi.org/10.21475/ajcs.22.16.03.p2925.
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The aim of this study was to assess resistance to frost in Arabica coffees with introgression of Coffea racemosa. The field experiment (Londrina, Paraná, Brazil) was assessed after two consecutive frosts in June 2011. Eleven F2BC5 Arabica coffee lines with introgression of C. racemosa were assessed 52 months after planting. C. arabica cultivars IAPAR 59, Tupi IAC 1669-33, Catuaí Vermelho IAC 99 and Mundo Novo IAC 376-4 were used as sensitive controls. Foliar damages assessments were carried out 20 days after exposure to freezing temperatures. Foliar damages were scored using grades ranging from 1 to 5, where: grade 1 = no damage; and 5 grade = from 75.01 to 100.00% damaged leaf area. Levels of foliar damage (e.g. no damage – very severe damages) were classified according to the mean grades of the assessments. Severe leaf damage was observed in the controls, while nine lines showed moderate damage. H0107-32 line is the most resistant to frost, and is the only one which presented slight leaf damage
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Guo, Jiamin, Jiongliang Wu, Junhua Guo i Zhiyu Jiang. "A Damage Identification Approach for Offshore Jacket Platforms Using Partial Modal Results and Artificial Neural Networks". Applied Sciences 8, nr 11 (6.11.2018): 2173. http://dx.doi.org/10.3390/app8112173.
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This paper presents a damage identification method for offshore jacket platforms using partially measured modal results and based on artificial intelligence neural networks. Damage identification indices are first proposed combining information of six modal results and natural frequencies. Then, finite element models are established, and damages in structural members are assumed by reducing the structural elastic modulus. From the finite element analysis for a training sample, both the damage identification indices and the damages are obtained, and neural networks are trained. These trained networks are further tested and used for damage prediction of structural members. The calculation results show that the proposed method is quite accurate. As the considered measurement points of the jacket platform are near the waterline, the prediction errors keep below 8% when the damaged members are close to the waterline, but may rise to 16.5% when the damaged members are located in deeper waters.
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Yuan, Xiaoqing, Naqash Azeem, Azka Khalid i Jahanzeb Jabbar. "Vibration Energy at Damage-Based Statistical Approach to Detect Multiple Damages in Roller Bearings". Applied Sciences 12, nr 17 (26.08.2022): 8541. http://dx.doi.org/10.3390/app12178541.
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This study proposes a statistical approach based on vibration energy at damage to detect multiple damages occurring in roller bearings. The analysis was performed at four different rotating speeds—1002, 1500, 2400, and 3000 RPM—following four different damages—inner race, outer race, ball, and combination damage—and under two types of loading conditions. These experiments were performed on a SpectraQuest Machinery Fault Simulator™ by acquiring the vibration data through accelerometers under two operating conditions: with the bearing loader on the rotor shaft and without the bearing loader on the rotor shaft. The histograms showed diversity in the defected bearing as compared to the intact bearing. There was a marked increase in the kurtosis values of each damaged roller bearing. This research article proposes that histograms, along with kurtosis values, represent changes in vibration energy at damage that can easily detect a damaged bearing. This study concluded that the vibration energy at damage-based statistical technique is an outstanding approach to detect damages in roller bearings, assisting Industry 4.0 to diagnose faults automatically.
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Kizha, Anil Raj, Evan Nahor, Noah Coogen, Libin T. Louis i Alex K. George. "Residual Stand Damage under Different Harvesting Methods and Mitigation Strategies". Sustainability 13, nr 14 (8.07.2021): 7641. http://dx.doi.org/10.3390/su13147641.
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A major component of sustainable forest management are the stands left behind after the logging operation. Large mechanized harvesting equipment involved in current forest management can inflict damage on residual trees; and can pose a risk of mortality from diseases, natural calamities, and/or degrade future economic value. The primary objective of this study was to evaluate the residual stand damage under different harvesting methods and silvicultural prescriptions i.e., crop tree release (CTR), diameter limit cut (DLC), and overstory removal (OSR). The second objective was to evaluate the intensity and frequency of damage occurring on the bole, canopy, and root at tree and stand level. The third objective was to document strategies adopted globally to minimize stand damage due to timber harvesting. Five harvest blocks implementing three silvicultural prescriptions, were selected as the treatments across two different industrial timberlands in central and northern Maine (Study Site (SS) I and II, respectively). A hybrid cut-to-length (Hyb CTL) and whole-tree (WT) harvesting method were employed for conducting the harvest in SS I and II, respectively. Systematic transect sampling was employed to collect information on type, frequency, and intensity of damages. The inventory captured 41 and 8 damaged trees per hectare with 62 and 22 damages per hectare from SS I and SS II respectively. Bole damage was the most frequent damage across all treatments. The Hyb CTL had lower damage density (damage per ha) and severity compared to WT. The average number of trees damaged per ha was higher for CTR prescriptions compared to DLC. There were no significant differences in the height of the damages from the ground level between treatments within each study site; however, there was a significant difference between the study sites. Species damaged was directly related to the residual trees left behind and was dominated by American beech, yellow birch, sugar maple, and eastern hemlock. Finally, the study provides strategies that can be adopted at different forest managerial phases to mitigate residual stand damage.
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Dhokane, Mr Rahul. "CAR DAMAGE DETECTION USING CNN". INTERANTIONAL JOURNAL OF SCIENTIFIC RESEARCH IN ENGINEERING AND MANAGEMENT 08, nr 04 (12.04.2024): 1–5. http://dx.doi.org/10.55041/ijsrem30508.
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In today's modern society, automobiles play a crucial role, and the automatic classification of car damages holds particular significance for the auto insurance industry. Our proposed solution involves the implementation of two Convolutional Neural Network (CNN) models. Specifically, the VGG16 model is employed to identify and assess the location and severity of car damage, while the Mask R-CNN is utilized to accurately mask the damaged regions. Both models collectively provide valuable insights into the extent. The CNN models effectively filter out images without damages, allowing only those with identified damage to be passed on to the object detection model. This strategic approach enhances the overall performance of the model. The core objective of this research project is to achieve maximum accuracy through the utilization of CNN models. TensorFlow, Key Words: E-commerce, Car Damage, Detection, Classification, VGG, Mask RCNN, Severity, Location, Masking
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Dhakal, Rajesh P. "Damage to non-structural components and contents in 2010 Darfield earthquake". Bulletin of the New Zealand Society for Earthquake Engineering 43, nr 4 (31.12.2010): 404–11. http://dx.doi.org/10.5459/bnzsee.43.4.404-411.
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This paper describes the performance of (or damage to) non-structural components and contents in buildings during the 4th September 2010 Darfield (Canterbury) earthquake and the subsequent aftershocks. Even in buildings with little damage to their structural systems, non-structural and content damages were significant; and these damages were reported to have increased during the aftershocks (especially those of magnitude 5 and higher). Most commonly damaged non-structural components were brick chimneys, parapets, ceilings, facades, internal walls and windows. The nature and extent of damages in each of these components are discussed in this paper with the help of typical damage photos taken after the earthquake. The extent of content damage in a building was dependent on its usage; typically buildings using racks/shelves for displaying commodities (such as library, departmental stores, liquor shops etc) suffered significantly greater loss from content damage than residential houses, office buildings and other types of commercial buildings.
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Meshkova, Valentyna L., Iryna M. Sokolova, Serhii O. Yeroshenko i Lesya M. Koval. "Effect of buds manually removal and their damage by large pine weevil (Hylobius abietis L.) on Scots pine seedlings in Siversky Donets river valley". Наукові праці Лісівничої академії наук України, nr 17 (25.10.2018): 113–20. http://dx.doi.org/10.15421/411826.
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Large pine weevil (Hylobius abietis L.) damages different organs of Scots pine (Pinus sylvestris L.) seedlings in unclosed plantations, including foliage, buds, stem bark and roots. Simulated damage of respective organs, particularly debudding is one of the ways to evaluate qualitative and quantitative influence of such damage on tree condition.
The aim of research was to evaluate the dependence of Scots pine seedlings mortality and height increment on artificial and large pine weevil caused bud damage.
The growth of apical shoots of Scots pine seedlings was registered since the beginning of May to the end of June. Development of new shoots in seedlings with manually bud removal or large pine weevil damage started in beginning of May and continued in July.
Mortality of Scots pine seedlings with 20% of lateral buds damaged did not differ from that in undamaged plants. The seedlings with apical and lateral buds manually removed as well as with apical and over 70% lateral buds damaged by large pine weevil have died in the year of treatment or damage. The seedlings with apical buds damaged as well as with apical and over 50% lateral buds damaged died in the 4th year after damage.
Removal or damage up to 50% lateral buds did not affect the growth of Scots pine seedlings. Height increment of seedlings with apical buds manually removed or damaged by large pine weevil did not differ significantly in May and June of the year of treatment or damage. In July the height increment was statistically greater in the variant with manually removal of apical bud.
Previously suggested scale of Scots pine seedlings bud damage satisfactory reflects the score of large pine weevil injuriousness.
We can suggest that height increment in the next years after bud damage does not depend on damage way and intensity but mainly on ecological conditions.
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C. Santos, Juliana, Marcus V. G. de Morais, Marcela R. Machado, Ramon Silva, Erwin U. L. Palechor i Welington V. Silva. "Beam-like damage detection methodology using wavelet damage ratio and additional roving mass". Frattura ed Integrità Strutturale 16, nr 62 (22.09.2022): 349–63. http://dx.doi.org/10.3221/igf-esis.62.25.
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Early damage detection plays an essential role in the safe and satisfactory maintenance of structures. This work investigates techniques use only damaged structure responses. A Timoshenko beam was modeled in finite element method, and an additional mass was applied along their length. Thus, a frequency-shift curve is observed, and different damage identification techniques were used, such as the discrete wavelet transform and the derivatives of the frequency-shift curve. A new index called wavelet damage ratio(WDR) is defined as a metric to measure the damage levels. Damages were simulated like a mass discontinuity and a rotational spring (stiffness damage). Both models were compared to experimental tests since the mass added to the structure is a non-destructive tool. It was evaluated different damage levels and positions. Numerical results showed that all proposed techniques are efficient techniques for damage identification in Timoshenko's beams concerning low computational cost and practical application.
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Duvnjak, Ivan, Domagoj Damjanović, Marko Bartolac i Ana Skender. "Mode Shape-Based Damage Detection Method (MSDI): Experimental Validation". Applied Sciences 11, nr 10 (18.05.2021): 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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Fauzan, B. Istijono, F. A. Ismail, Y. Narny i Y. S. Putra. "Non-engineering house damage after the February 25th, 2022 West Pasaman Earthquake". IOP Conference Series: Earth and Environmental Science 1244, nr 1 (1.09.2023): 012020. http://dx.doi.org/10.1088/1755-1315/1244/1/012020.
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Abstract The earthquake that occurred on February 25, 2022 with a magnitude of M6.2 in West Pasaman Regency, West Sumatera has resulted in many losses such as casualties and damages to infrastructure, especially residential buildings. To determine the level of damage to community houses due to the earthquake, a rapid visual assessment survey was conducted with the National Agency for Disaster Countermeasure (BNPB) and 100 Civil Engineering students. The Method used in this survey is based on the Public Work Minister Regulation, which categorizes the damaged houses into 3 categories, namely light, moderate and heavy damage. Based on the results of the assessment, the damage generally occurred on the walls and structural elements of the houses. The damages is caused by human error factors such as lack of planning, poor construction implementation, site selection and selection of quality building materials that were not in accordance with earthquake safe house building standards. One of the efforts to overcome the problem of the damage is to strengthen the house using a ferrocement layer. The level of buildings damage based on the distance from the earthquake center and the implementation of retrofitting on the damaged houses are also discussed in this paper.
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Raj, R. Melvin, Jyosthna R, Ramya Madhuri N, Akshay Sunny R i Pratima A. "Damage Detection of An Automobile". International Journal of Engineering Research in Computer Science and Engineering 9, nr 10 (13.10.2022): 61–64. http://dx.doi.org/10.36647/ijercse/09.10.art014.
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As a result of the proliferation of automobile in- dustries today. There have been an increasing number of car accidents, not all of which are serious, but the automobile is damaged. Detecting automobile damage at the site of an accident using images is exceptionally beneficial as it may significantly lower the cost of processing the insurance reimbursement process while also providing more convenience to automobile users. In most cases, this damage is detected and assessed manually from the car’s images during the car evaluation process. In this paper, we worked on the problem of automation of vehicle damage detection which can be used by insurance companies to automate the process of vehicle insurance claims in a rapid fashion. The recent advances in computer vision largely due to the adoption of fast, scalable, and end-to-end trainable Convolutional Neural Networks make it technically feasible to recognize vehicle damages using semantic segmentation. We manually collected and annotated images from various online sources containing different types of vehicle damages and we used U-NET architec- ture to detect the damage of an automobile.
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Mahendran, G., Chandrasekaran Kesavan i S. K. Malhotra. "Damage Detection in Laminated Composite Beams, Plates and Shells Using Dynamic Analysis". Applied Mechanics and Materials 787 (sierpień 2015): 901–6. http://dx.doi.org/10.4028/www.scientific.net/amm.787.901.
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Vibration-based technique to detect damage in laminated composite beams, rectangular plates and cylindrical shells is presented in this paper.A parameter called damage indicator calculated based on mode shape curvature isused in this studyto detect the location and size of small damages accurately in laminated composite structures. Through numerical analysis of laminated compositecantilevered beam, plate and cylindrical shell models with edge crack as damage, the absolute change inthe damage indicator is localized in the region of damage. Thechange in damage indicatorincreases withincreasing size of damage. Thisinformationis obtained by considering two cases of damage sizes (case-1 and case-2)in the structures. Finite element methodbased commercial analysis package ANSYSis used to obtain thenormalized displacement mode shapesof the three models both for intact and damaged states and then the damage indicator is calculated from the mode shapes data.The numerical analysis to detect damage is followed by validation by experimental modal testing.
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Le, Thanh-Cao, Duc-Duy Ho, Chi-Thien Nguyen i Thanh-Canh Huynh. "Structural Damage Localization in Plates Using Global and Local Modal Strain Energy Method". Advances in Civil Engineering 2022 (18.05.2022): 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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He, Guo Jing, Fei Xie i Lan Xie. "The Methods of Damage Localization and Assessment for Long-Span Reinforced Concrete Arch Bridge". Applied Mechanics and Materials 90-93 (wrzesień 2011): 1785–90. http://dx.doi.org/10.4028/www.scientific.net/amm.90-93.1785.
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The increase in axle load and speed, the worse of service environment and the deterioration of existing bridges result in various of damages in structures. In order to ensure the safety of the structure, it is essential to assess the performance of the structure. In this paper, based on the frequency changes of the damaged and undamaged structure, damage positioning indicator method was used to locate the damage of the structure. Damage assessment method (SSZD) based on modified modal strain energy method was used to assess the extent of structural damage. The results show that this method can be used to locate and assess the structural damage accurately.
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Halilović, Velid, Dalibor Ballian, Besim Balić, Mario Šarić, Jelena Knežević i Jusuf Musić. "Istraživanje mehaničkih oštećenja stabala jele i drugih vrsta tijekom eksploatacije – Slučaj Šumarije „Glamoč“". Šumarski list 144, nr 3-4 (30.04.2020): 149–58. http://dx.doi.org/10.31298/sl.144.3-4.4.
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Mechanisation used in forest utilisation has an impact on the occurrence of damage in stand and on forest land. The research in this work had the objective of determining damage on fir trees and other tree species during felling and processing of trees and their skidding using the forest cable-skidder. The research wasconducted in mixed beech and fir forests in the area of FMA “Glamočko”, M.U. “Hrbinje-Kujača”. The following data were gathered on damaged trees: tree type, breast height diameter, economic importance of the tree, amount of damage, location of damage, cause of damage, types of damage. Damage was recorded on a total of 305 trees, 133 trees of silver fir (Abies alba), 130 trees of European beech (Fagus sylvatica), 33 trees of European spruce (Picea abies), 8 trees of rowan/mountain-ash (Sorbusaucuparia) and one tree of sycamore (Acer pseudoplatanus). The overall damage intensity was 18.7%, but together with the old damages, the overall number of ‘wounds’ is 496. According to this, when the old damage isalso considered, then the intensity of damage amounts to 30.6%. The largest amount of damage is in the diameter sub-class ranging from 10 to 14.99 cm. According to the cause of damage, the largest amount of damage occurred during the wood extraction phase (217 trees), while during the felling phase, 88 trees or 29% were damaged. Since the wood extraction phase is divided into the winching and skidding phases, the total number of damaged trees during the winching phase amounted to 157 or 52%, while during the skidding phase, the number of damaged trees was 60 or 19%. To reduce damage to the trees during following operations in forest utilisation, it is necessary to perform more frequent training of all employees working on forest utilisation, to increase controls in execution of operations during forest utilisation, modernise machines used during forest exploitation, and in quality manner open compartments with forest road infrastructure.
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Bhargav Sai, Cherukuri, i D. Mallikarjuna Reddy. "Dynamic Analysis of Faulty Rotors through Signal Processing". Applied Mechanics and Materials 852 (wrzesień 2016): 602–6. http://dx.doi.org/10.4028/www.scientific.net/amm.852.602.
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In this study, an effective method based on wavelet transform, for identification of damage on rotating shafts is proposed. The nodal displacement data of damaged rotor is processed to obtain wavelet coefficients to detect, localise and quantify damage severity. Because the wavelet coefficients are calculated with various scaled indices, local disturbances in the mode shape data can be found out in the finer scales that are positioned at local disturbances. In the present work the displacement data are extracted from the MATLAB model at a particular speed. Damage is represented as reduction in diameter of the shaft. The difference vectors between damaged and undamaged shafts are used as input vectors for wavelet analysis. The measure of damage severity is estimated using a parameter formulated from the distribution of wavelet coefficients with respect to the scales. Diagnosis results for different damage cases such as single and multiple damages are presented.
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Yoon, Junho, Jeongyun Lee i Won Jong Yoo. "Removal of Plasma-Induced Physical Damage Formed in Nanoscale Three-Dimensional FinFETs". Nano 12, nr 08 (sierpień 2017): 1750099. http://dx.doi.org/10.1142/s1793292017500990.
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During plasma etching for fin patterning in the three-dimensional (3D) FinFET structure, the exposure of the Si surface to plasma with reactive ions can induce physical damages, resulting in the degradation of electrical properties of the device. In this study, we evaluated the damage with a measurable value by simulation and surface damage analyses using HR-TEM and RBS. As a result, the degree of the damaged layer was strongly dependent on the energy of the ions bombarding the Si substrate during plasma etching. The damage was quantified with the interface defect density measured by the charge pumping method. Plasma etching with high ion energy showed approximately one order of magnitude higher defect density than that with low ion energy and/or wet etching with no ion bombardment. We introduced Si soft treatment (with very low ion energy) to remove the damaged layer. The Si soft treatment was very effective to remove the damage on a highly damaged silicon surface. However, the Si soft treatment itself increased the number of defects for a low damage silicon surface.
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Stoykov, Stanislav, Emil Manoach i Maosen Cao. "Vibration Based Damage Detection of Rotating Beams". MATEC Web of Conferences 148 (2018): 14008. http://dx.doi.org/10.1051/matecconf/201814814008.
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The early detection and localization of damages is essential for operation, maintenance and cost of the structures. Because the frequency of vibration cannot be controlled in real-life structures, the methods for damage detection should work for wide range of frequencies. In the current work, the equation of motion of rotating beam is derived and presented and the damage is modelled by reduced thickness. Vibration based methods which use Poincaré maps are implemented for damage localization. It is shown that for clamped-free boundary conditions these methods are not always reliable and their success depends on the excitation frequency. The shapes of vibration of damaged and undamaged beams are shown and it is concluded that appropriate selection criteria should be defined for successful detection and localization of damages.
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Zhang, Ning, Zhuo Bin Wei i Sen Wu. "Experimentation Study of Damage Identification for Steel-Frame Structure Based on AR Model". Advanced Materials Research 490-495 (marzec 2012): 334–38. http://dx.doi.org/10.4028/www.scientific.net/amr.490-495.334.
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By using the AR (Auto-regressive) self-regression model, structure acceleration data are fitted. By using fitted coefficients, the characteristic vector of structure damage is constructed. Based on the Mahalanobis distance of the characteristic vectors under different states, the index of structure damage is designed. By comparing the characteristic index of healthy structures and the damaged ones, damages can be detected. By an experiment of damage identification on steel-frame structure model, the effectiveness of the method is validated.
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NASERALAVI, S. S., S. GERIST, E. SALAJEGHEH i J. SALAJEGHEH. "ELABORATE STRUCTURAL DAMAGE DETECTION USING AN IMPROVED GENETIC ALGORITHM AND MODAL DATA". International Journal of Structural Stability and Dynamics 13, nr 06 (2.07.2013): 1350024. http://dx.doi.org/10.1142/s0219455413500247.
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This paper addresses a proficient strategy for detection of structural damages in details using the variations of eigenvalues and eigenvectors. There are two concerns in this study. First, the severity of damage can vary within the damaged elements; second, it is possible that the damage extents do not exactly match the pre-generated finite element mesh. The first concern forms the motivation for employing the proper damage functions to model the elemental damages, and the second for considering the nodal positions as design variables. To obtain the design variables, an improved genetic algorithm is introduced in which two new operators are embedded. This strategy is applied to a beam and a plate structure as the cases of study. The results demonstrate the applicability and efficiency of the proposed algorithm in elaborate damage detections.
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Hu, Zhixiang, i Peiguan Zhang. "Damage Identification of Structures Based on Smooth Orthogonal Decomposition and Improved Beetle Antennae Search Algorithm". Advances in Civil Engineering 2021 (27.02.2021): 1–14. http://dx.doi.org/10.1155/2021/8857356.
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A novel damage identification method that utilizes the smooth orthogonal decomposition (SOD) combined with the improved beetle antennae search algorithm (BAS) presented by previous scholars is proposed. Firstly, the damage index which can track the curvature changing of mode shape identified by the SOD method is generated by an adaptive polynomial fit method. The locations of structure damages are determined according to the damage index. Thus, the number of possible damaged elements needed to be taken into account can be reduced when calculating the degree of damage. Then, the reduction in the stiffness at the damage location of the structure is calculated by the improved BAS in which the fitness function is constructed by calculated frequencies of the damaged structure in each iteration and the modal frequencies obtained by SOD. The BAS algorithm is improved through a fusion strategy of simulated annealing theory. Thus, the improved BAS algorithm is efficient and adaptive. The effect of this combined application in damage identification has been verified by numerical examples of a simply supported beam with single damage and a cantilever beam with double damage. The numerical results show that this combined algorithm exhibits high reliability in damage identification of beam-like structures.
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Shpylova, Yuliia, Oleh Bendasiuk i Volodymyr Lagodiienko. "FOREIGN PRACTICES OF DAMAGE ASSESSMENT FOR POST-WAR ENVIRONMENTAL RESTORATION". Innovation and Sustainability, nr 1 (31.03.2023): 140–49. http://dx.doi.org/10.31649/ins.2023.1.140.149.
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The article examines in detail the experience of the Iraq-Kuwait war in terms of receiving compensation for the damage caused by the war to the surrounding natural environment. In particular, the "Habitat Equivalency Analysis" methodology, which was used to determine the amount of compensatory restoration to cover losses in ecological services that were provided by natural resources before their damage. The methodology aims to estimate the total loss of services provided by a damaged or lost habitat. The FAO methodology for damage and loss assessment in agriculture was also analyzed. In which the focus is on the continuous collection of data on damage and loss in agriculture, recording the smaller and localized effects of disasters. The focus in the review of the methodology is focused on the determination of damages and losses in forestry. Such components as: damages and losses of forestry; loss of forestry production; loss of forestry products; damage to forestry assets. It was established that the considered methodology is suitable for determining the damage caused by military actions for forest resources in the part that directly concerns the forest cover.
One of the areas of damage assessment in the nature management sector is the determination of options for primary (restoration) recovery. This stage refers to actions aimed at restoring the damaged resource and, if possible, returning it to the basic level (before the war), which involves establishing recovery goals; determination of primary restoration options; selection of primary restoration options; assessment of intermediate damages, etc. The choice of primary restoration options should be the result of an evaluation process based on the following criteria, but not limited to cost of implementation; the length of time it will take for the recovery to be effective; probability of success, etc.
The next steps should be a large-scale damage assessment in accordance with generally accepted methods, development of ways to restore the natural environment and identification of funds to minimize or eliminate the damage caused to the elements of the environment or natural resources.
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Meng, Lijun, Zhengang Guo i Chenglong Ma. "Research on multiple damage localisation based on fusion of the Lamb wave ellipse algorithm and RAPID algorithm". Insight - Non-Destructive Testing and Condition Monitoring 66, nr 1 (1.01.2024): 34–40. http://dx.doi.org/10.1784/insi.2024.66.1.34.
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Current damage localisation methods often require many sensors and complex signal processing methods. This paper proposes a fusion algorithm based on elliptical localisation and the reconstruction algorithm for probabilistic inspection of damage (RAPID) to locate and image multiple damages. Experimental verification of the damage algorithm was conducted. An ultrasonic probe was used to excite Lamb signals on an aluminium alloy plate, the ultrasonic response signals at different positions within the plate under multiple damages were measured and the constructed algorithm was employed to image the damage location. In the experiment, this method improved localisation efficiency by excluding invalid sensing paths in the sensor network, saving 31.32% of computational time. When some sensors in the sensor network were damaged, this algorithm ensured a positioning accuracy with a positioning error of 5.83 mm. Finally, the algorithm was used to locate multiple damages in the sensor network and the results showed the good robustness of the algorithm.
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Pagar, Prof Nilima. "Survey Paper on Road Damage Detection and Reporting System Using Fully Connected CNN". INTERANTIONAL JOURNAL OF SCIENTIFIC RESEARCH IN ENGINEERING AND MANAGEMENT 08, nr 01 (8.01.2024): 1–10. http://dx.doi.org/10.55041/ijsrem27939.
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Many rural and metropolitan towns, as well as road authorities, encounter challenges in mapping surface damages resulting from numerous sources such strong rains, natural catastrophes, or other events that cause cracks and holes to emerge on the road surface. These organizations or private entities look out for solutions to implement automated methods of reporting damages on a surface of the road. The majority of the time, they lack the equipment needed to map the damage to the roadways. One of the main issues facing commuters is the numerous damaged road portions they must navigate. This causes riders to often reduce their pace, losing a great deal of time and energy and lengthening the time it takes them to reach their destinations. When driving at a faster speed and suddenly encountering a damaged section of the road, road damage can frequently be fatal. Furthermore, it is capable of identifying recurring bottlenecks, determining their cause, and suggesting remedies. The majority of the time, these traffic jams are brought on by road damage, which forces commuters to go far slower than is ideal. Keywords: Smart road damage detection, classification, Machine Learning, Image segmentation, CNN, fully connected CNNs, RDD System (Road Damage Detection System).
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Khan, Mehran, Swarup Mahato, Darius Eidukynas i Tomas Vaitkunas. "Influence determination of damage to mechanical structure based on modal analysis and modal assurance criterion". Vibroengineering PROCEDIA 42 (16.05.2022): 27–32. http://dx.doi.org/10.21595/vp.2022.22554.
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Mechanical damages in structures changes its geometry in various ways. However, if damage size comparing to structure size is small, thus observation of this damage could be hard or even impossible in some cases. For this reason, changes in structure’s vibration responses are investigated nowadays. The objective of this research is to investigate the influence of damage size to the vibration response of the mechanical structure – aluminum alloy plate. To achieve this aim, modal analysis of a reference, i.e. health, and multiple damaged structures using ANSYS Workbench, and calculation of modal assurance criterion (MAC) using Matlab were carried out in this research. During this research 6 different damage sizes were modelled and its vibration response was compared to the health one. Obtained results revealed that the bending modes rarely shows any trend towards damages scenario. But, when observing the MAC values matrices, the values related to torsional modes even on the diagonal of the matrices decrease as the damage size increases, which indicates that the damage has more influence on the torsional modes.
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Liu, Wei Feng, Shu Xia Zhang, Wei Liu i Ling Ling Zhou. "Study of Ecological Environment on Assessment Model of Ecosystem Damage Caused by Oil Spill in Ocean". Advanced Materials Research 908 (marzec 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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Lee, Eun-Taik, i Hee-Chang Eun. "Disassembling-Based Structural Damage Detection Using Static Measurement Data". Shock and Vibration 2019 (31.10.2019): 1–12. http://dx.doi.org/10.1155/2019/6073828.
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Damage detection methods can be classified into global and local approaches depending on the division of measurement locations in a structure. The former utilizes measurement data at all degrees of freedom (DOFs) for structural damage detection, while the latter utilizes data of members and substructures at a few DOFs. This paper presents a local method to detect damages by disassembling an entire structure into members. The constraint forces acting at the measured DOFs of the disassembled elements at the damaged state, and their internal stresses, are predicted. The proposed method detects locally damaged members of the entire structure by comparing the stress variations before and after damage. The static local damage can be explicitly detected when it is positioned along the constraint load paths. The validity of the proposed method is illustrated through the damage detection of two truss structures, and the disassembling (i.e., local) and global approaches are compared using numerical examples. The numerical applications consider the noise effect and single and multiple damage cases, including vertical, diagonal, and chord members of truss structures.
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Huang, Ming-Chih, Yen-Po Wang i Ming-Lian Chang. "Damage Detection of Structures Identified with Deterministic-Stochastic Models Using Seismic Data". Scientific World Journal 2014 (2014): 1–14. http://dx.doi.org/10.1155/2014/879341.
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A deterministic-stochastic subspace identification method is adopted and experimentally verified in this study to identify the equivalent single-input-multiple-output system parameters of the discrete-time state equation. The method of damage locating vector (DLV) is then considered for damage detection. A series of shaking table tests using a five-storey steel frame has been conducted. Both single and multiple damage conditions at various locations have been considered. In the system identification analysis, either full or partial observation conditions have been taken into account. It has been shown that the damaged stories can be identified from global responses of the structure to earthquakes if sufficiently observed. In addition to detecting damage(s) with respect to the intact structure, identification of new or extended damages of the as-damaged counterpart has also been studied. This study gives further insights into the scheme in terms of effectiveness, robustness, and limitation for damage localization of frame systems.
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Hajeb, Masoud, Sadra Karimzadeh i Masashi Matsuoka. "SAR and LIDAR Datasets for Building Damage Evaluation Based on Support Vector Machine and Random Forest Algorithms—A Case Study of Kumamoto Earthquake, Japan". Applied Sciences 10, nr 24 (14.12.2020): 8932. http://dx.doi.org/10.3390/app10248932.
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The evaluation of buildings damage following disasters from natural hazards is a crucial step in determining the extent of the damage and measuring renovation needs. In this study, a combination of the synthetic aperture radar (SAR) and light detection and ranging (LIDAR) data before and after the earthquake were used to assess the damage to buildings caused by the Kumamoto earthquake. For damage assessment, three variables including elevation difference (ELD) and texture difference (TD) in pre- and post-event LIDAR images and coherence difference (CD) in SAR images before and after the event were considered and their results were extracted. Machine learning algorithms including random forest (RDF) and the support vector machine (SVM) were used to classify and predict the rate of damage. The results showed that ELD parameter played a key role in identifying the damaged buildings. The SVM algorithm using the ELD parameter and considering three damage rates, including D0 and D1 (Negligible to slight damages), D2, D3 and D4 (Moderate to Heavy damages) and D5 and D6 (Collapsed buildings) provided an overall accuracy of about 87.1%. In addition, for four damage rates, the overall accuracy was about 78.1%.
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Yang, X. H., Y. Zhang, Y. T. Hu i C. Y. Chen. "Continuum Damage Mechanics for Thermo-Piezoelectric Materials". Journal of Mechanics 22, nr 2 (czerwiec 2006): 93–98. http://dx.doi.org/10.1017/s172771910000438x.
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AbstractWith rapidly increasing use of piezoelectric materials in high-temperature environment, it is becoming increasingly important for reliable design of piezoelectric devices to study thermo-electroelastic damage and fracture mechanism. As the first step, a thermo-piezoelectric damage constitutive model is presented from continuum damage mechanics and effective properties of a damaged material are connected with both damages and the initial coefficients according to the theorem of energy equivalence in this paper. Then the finite element equations for a thermo-electroelastic damage problem are given by use of the virtual work principle. Finally, as a numerical illustration example, damage fields around a crack-tip in a three-point bending PZT-5H beam subjected to different thermal loads are calculated and analyzed. It is shown from both the damage curves and contours that influence of environmental temperature on the mechanical damage distribution is great but slight on the electrical damage.
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Cao, Jiayu, Jianbin Liao, Jin Yan i Hongliang Yu. "Enhancing Damage Localization in GFRP Composite Plates: A Novel Approach Using Feedback Optimization and Multi-Label Classification". Processes 12, nr 2 (18.02.2024): 414. http://dx.doi.org/10.3390/pr12020414.
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Damage localization in GFRP (glass-fiber-reinforced polymer) composite plates is a crucial research area in marine engineering. This study introduces a feedback-based damage index (DI) combined with multi-label classification to enhance the accuracy of damage localization and address scenarios involving multiple damages. The research begins with the creation of a modal database for yachts’ GFRP composite plates using finite element modeling (FEM). A method for deriving a feedback-weighted matrix, based on the accuracy of the DI, is then developed. Sensitivity analysis reveals that the feedback DI is 50% more sensitive than the traditional DI, reducing false positives and missed detections. The associated feedback-weighted matrix depends solely on the structural shape, ensuring its transferability. To address the challenge for localizing multiple damages, a multi-label classification approach is proposed. The synergy between the feedback optimization and multi-label classification enables the rapid and precise localization of multiple damages in GFRP composite plates. Modal testing on damaged GFRP plates confirms the enhanced accuracy for combining the feedback DI with multi-label classification for pinpointing damage locations. Compared with traditional methods, this feedback DI method improves sensitivity, while multi-label classification effectively handles multiple damage scenarios, enhancing the overall efficiency of the damage diagnosis. The effectiveness of the proposed methods is validated through experimentation, offering robust theoretical support for composite plate damage diagnostics.
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Zhao, Bingchao, Pan Chen, Jingbin Wang, Jingui Zhang i Di Zhai. "A Comprehensive Evaluation and Analysis of Ground Surface Damage Due to Mining under Villages Based on GIS". Applied Sciences 13, nr 18 (8.09.2023): 10136. http://dx.doi.org/10.3390/app131810136.
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This paper aims to evaluate the severities and causes of ground surface building and cropland damages after coal mining in a better way, and to clarify the correlation between the damage assessment indexes that influence mining. Against the backdrop of multi-seam mining in certain coal mines in China, the estimated results of each displacement and deformation were analyzed using GIS technology. The damage range determined for each deformation index is divided according to the displacement and deformation combined with the virtue of damage judgment threshold. The damage ranges on the ground surface based on the comprehensive value of each displacement and deformation index were obtained through superimposing those ranges delineated by each displacement and deformation index, and the law on influence from displacement indexes upon various levels of damage was analyzed in a quantitative manner accordingly. The results showed that coal mining destroyed 14 buildings and a cropland area of 11.96 hm2; among them, building damage was only associated with displacement indexes E (horizontal deformation) and T (inclined deformation). Seven buildings were solely destroyed by T alone; five buildings were solely damaged by E; two buildings were damaged jointly by E and T; and, moreover, with the aggravation in building damage level, the proportion of building damage due to E decreased while the proportion of building damage under the same level due to T increased. Regarding cropland destruction, the damage due to T accounted for 33.48% while the damage jointly caused by W (Subsidence), E and T accounted for 30.45%. Moreover, the proportion of damaged cropland area due to inclined deformation T was positively correlated with cropland damage level. These findings can provide a reference for rational judgment regarding civilian building and cropland destruction on the ground surface after coal mining.
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Yang, Qun, i Dejian Shen. "Learning Damage Representations with Sequence-to-Sequence Models". Sensors 22, nr 2 (7.01.2022): 452. http://dx.doi.org/10.3390/s22020452.
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Natural hazards have caused damages to structures and economic losses worldwide. Post-hazard responses require accurate and fast damage detection and assessment. In many studies, the development of data-driven damage detection within the research community of structural health monitoring has emerged due to the advances in deep learning models. Most data-driven models for damage detection focus on classifying different damage states and hence damage states cannot be effectively quantified. To address such a deficiency in data-driven damage detection, we propose a sequence-to-sequence (Seq2Seq) model to quantify a probability of damage. The model was trained to learn damage representations with only undamaged signals and then quantify the probability of damage by feeding damaged signals into models. We tested the validity of our proposed Seq2Seq model with a signal dataset which was collected from a two-story timber building subjected to shake table tests. Our results show that our Seq2Seq model has a strong capability of distinguishing damage representations and quantifying the probability of damage in terms of highlighting the regions of interest.
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Ai, Demi, Hui Luo i Hongping Zhu. "Diagnosis and validation of damaged piezoelectric sensor in electromechanical impedance technique". Journal of Intelligent Material Systems and Structures 28, nr 7 (28.07.2016): 837–50. http://dx.doi.org/10.1177/1045389x16657427.
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Piezoelectric sensor diagnosis and validity assessment as a prior component of structural health monitoring system are necessary in the practical application of electromechanical impedance technique. This article proposed an innovative sensor self-diagnosis process based on extracting the characterization of the real admittance (inverse of impedance) signature within a high-frequency range, which covered both diagnosis on damaged sensor after its installation and discrimination of sensor and structural damages during structural health monitoring process. Theoretical analysis was derived from the impedance model of piezoelectric-bonding layer-structure dynamic interaction system. Experimental investigations on piezoelectric sensor-bonded steel beam involved with structural damages of mass addition and notch damage were conducted to verify the process. It was found that the real admittance was reliable and critical in sensor diagnosis, and sensor faults of debonding, scratch, and breakage can be identified and differentiated from structural damage. Validity assessment of the diagnosed damaged sensor was addressed through resonant frequency shift method. The results showed that the validity of damaged sensor for structural health monitoring was inordinately depreciated by sensor damage. This article is expected to be useful for structural health monitoring application especially when damaged piezoelectric sensors existed.
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Drapikovskyi, Oleksandr, i Iryna Ivanova. "Property Damage Assessment Methods and Models due to Armed Aggression". Real Estate Management and Valuation 31, nr 3 (1.09.2023): 32–43. http://dx.doi.org/10.2478/remav-2023-0019.
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Abstract The paper deals with the conceptualization of the gross development value to assess direct damages and the restoration needs of lost, destroyed and damaged real estate as a result of armed aggression. A critical review of the existing practice of assessing property damage has been carried out. The measurement units of direct damages and the restoration needs, the evidence base used, the valuation methods for the determination of property damage are analyzed. The methodological potential of compounded cash flow models and the criteria for assessing their reliability is substantiated. A system of valuation models for calculating direct damages and restoration needs is proposed, depending on the category of real estate and market conditions at the valuation date. These valuation models are relatively simple to implement and understandable to the intended users of property damage valuation reports.
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Kim, Ju-Won, Kassahun Demissie Tola, Dai Quoc Tran i Seunghee Park. "MFL-Based Local Damage Diagnosis and SVM-Based Damage Type Classification for Wire Rope NDE". Materials 12, nr 18 (7.09.2019): 2894. http://dx.doi.org/10.3390/ma12182894.
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Wire ropes used in various applications such as elevators and cranes to safely carry heavy weights are vulnerable to breakage or cross-sectional loss caused by the external environment. Such damage can pose a serious risk to the safety of the entire structure because damage under tensile force rapidly expands due to concentration of stress. In this study, the magnetic flux leakage (MFL) method was applied to diagnose cuts, corrosion, and compression damage in wire ropes. Magnetic flux signals were measured by scanning damaged wire rope specimens using a multi-channel sensor head and a compact data acquisition system. A series of signal-processing procedures, including the Hilbert transform-based enveloping process, was applied to reduce noise and improve the resolution of signals. The possibility of diagnosing several types of damage was verified using enveloped magnetic flux signals. The characteristics of the MFL signals according to each damage type were then analyzed by comparing the extracted damage indices for each damage type. For automated damage type classification, a support vector machine (SVM)-based classifier was trained using the extracted damage indices. Finally, damage types were automatically classified as cutting and other damages using the trained SVM classifier.
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Nguyen, V. H., J. Mahowald, S. Maas i J. C. Golinval. "Use of Time- and Frequency-Domain Approaches for Damage Detection in Civil Engineering Structures". Shock and Vibration 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/872492.
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The aim of this paper is to apply both time- and frequency-domain-based approaches on real-life civil engineering structures and to assess their capability for damage detection. The methodology is based on Principal Component Analysis of the Hankel matrix built from output-only measurements and of Frequency Response Functions. Damage detection is performed using the concept of subspace angles between a current (possibly damaged state) and a reference (undamaged) state. The first structure is the Champangshiehl Bridge located in Luxembourg. Several damage levels were intentionally created by cutting a growing number of prestressed tendons and vibration data were acquired by the University of Luxembourg for each damaged state. The second example consists in reinforced and prestressed concrete panels. Successive damages were introduced in the panels by loading heavy weights and by cutting steel wires. The illustrations show different consequences in damage identification by the considered techniques.
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Elyiğit, Belkıs, i Cevdet Emin Ekinci. "A RESEARCH ON STRUCTURAL AND NON-STRUCTURAL DAMAGES AND DAMAGE ASSESSMENT IN REINFORCED CONCRETE STRUCTURES". NWSA Academic Journals 18, nr 2 (25.04.2023): 19–42. http://dx.doi.org/10.12739/nwsa.2023.18.2.1a0485.
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Zhang, Qing Xia, Zhong Dong Duan i Lukasz Jankowski. "Substructure Damages and Excitations Identification Using Measured Response". Applied Mechanics and Materials 501-504 (styczeń 2014): 843–46. http://dx.doi.org/10.4028/www.scientific.net/amm.501-504.843.
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This paper proposes a methodology on simultaneous identification of substructure excitation and damage. Structural damages are simulated by virtual distortions which are computed together with unknown excitations using the measured responses through the intact isolated substructure model; the damage extent and type is then recovered by a comparison of the virtual and actual distortions. Unknown factors are reduced greatly which allows the method to be applied on practical complex structure. The computational cost is cutoff sharply. A damaged nonlinearity aluminum beam is used in the experimental verification. Both load and damage are successfully identified.
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Ghaffarian, S., i N. Kerle. "TOWARDS POST-DISASTER DEBRIS IDENTIFICATION FOR PRECISE DAMAGE AND RECOVERY ASSESSMENTS FROM UAV AND SATELLITE IMAGES". ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W13 (4.06.2019): 297–302. http://dx.doi.org/10.5194/isprs-archives-xlii-2-w13-297-2019.
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<p><strong>Abstract.</strong> Often disasters cause structural damages and produce rubble and debris, depending on their magnitude and type. The initial disaster response activity is evaluation of the damages, i.e. creation of a detailed damage estimation for different object types throughout the affected area. First responders and government stakeholders require the damage information to plan rescue operations and later on to guide the recovery process. Remote sensing, due to its agile data acquisition capability, synoptic coverage and low cost, has long been used as a vital tool to collect information after a disaster and conduct damage assessment. To detect damages from remote sensing imagery (both UAV and satellite images) structural rubble/debris has been employed as a proxy to detect damaged buildings/areas. However, disaster debris often includes vegetation, sediments and relocated personal property in addition to structural rubble, i.e. items that are wind- or waterborne and not necessarily associated with the closest building. Traditionally, land cover classification-based damage detection has been categorizing debris as damaged areas. However, in particular in waterborne disaster such as tsunamis or storm surges, vast areas end up being debris covered, effectively hindering actual building damage to be detected, and leading to an overestimation of damaged area. Therefore, to perform a precise damage assessment, and consequently recovery assessment that relies on a clear damage benchmark, it is crucial to separate actual structural rubble from ephemeral debris. In this study two approaches were investigated for two types of data (i.e., UAV images, and multi-temporal satellite images). To do so, three textural analysis, i.e., Gabor filters, Local Binary Pattern (LBP), and Histogram of the Oriented Gradients (HOG), were implemented on mosaic UAV images, and the relation between debris type and their time of removal was investigated using very high-resolution satellite images. The results showed that the HOG features, among other texture features, have the potential to be used for debris identification. In addition, multi-temporal satellite image analysis showed that debris removal time needs to be investigated using daily images, because the removal time of debris may change based on the type of disaster and its location.</p>
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Todoroki, Akira, Masahito Ueda i Yoshinobu Shimamura. "Damage Monitoring of Thick CFRP Beam Using Electrical Impedance Changes". Key Engineering Materials 353-358 (wrzesień 2007): 1298–301. http://dx.doi.org/10.4028/www.scientific.net/kem.353-358.1298.
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Electrical resistance change method has been applied to monitor a delamination crack of a thin CFRP laminate. For a thick CFRP laminate, multiple delamination cracks are made with many matrix cracks, and the electric current in the thick CFRP laminate may not flow in the thickness direction due to the strong orthotropic electrical conductivity. The present study employs an electric impedance change method for the identification of damage location and dimension of the damaged area; applicability of the method is investigated experimentally using thick beam-type specimens fabricated from cross-ply laminates of 36 plies. After making the damage, electrical impedance was decreased. A residual stress relief model was proposed to explain the decrease. From the measured electrical impedance changes, the relationships between the electrical impedance changes and damages are obtained by means of response surfaces. The response surfaces estimated the damage location and dimension of the damaged area exactly even for the thick CFRP laminates. The electrical impedance change method can be used as an appropriate sensor for measurement of residual stress relief due to damages of thick CFRP laminates.
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Kim, Moon-Jeong, i Hee-Chang Eun. "Identification of damage-expected members of truss structures using frequency response function". Advances in Mechanical Engineering 9, nr 1 (styczeń 2017): 168781401668791. http://dx.doi.org/10.1177/1687814016687911.
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A damaged member in a truss structure leads to a variation in the initial responses of its adjacent members. A flexibility-based approach extracting from the modal data should be implemented as one of the structural damage detection methods. The frequency response function data as dynamic measurements provide more information on the system characteristics compared with modal data. Proper orthogonal modes from the frequency response functions extracted in the given frequency ranges and their modified forms can be utilized as damage indices to detect damages. This study considers damage detection of a truss structure using a frequency response function–based approach transformed to the proper orthogonal modes and a flexibility-based approach using the first few modal data for undamaged and damaged states. The utilization of these two methods is compared through numerical experiments on truss structures. The methods can rarely detect the damaged member accurately, but a group of damage-expected members is detected despite the existence of external noise. It is shown that the frequency response function–based approach can be utilized more explicitly than the flexibility-based approach.
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Yan, Wei, Wan Chun Li i Wei Wang. "Finite Element Model for Damage Detection in Three-Dimensional Cube Structures". Advanced Materials Research 430-432 (styczeń 2012): 1468–71. http://dx.doi.org/10.4028/www.scientific.net/amr.430-432.1468.
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Based on three-dimensional finite element method (FEM), an accurate electro-mechanical impedance (EMI) model for a damaged cube structure is established in the paper. The damages are simulated by the reduction in Young’s modulus in the certain area of the cube structure. A coupled structural system consisting of PZT patch, bond layer and host structure is taken into account. Both the effects of the damage severity and damage propagation on EMI signatures are then investigated. The numerical computation indicates that the present EMI model can be employed to detect the damages in the structures.
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Jin, Wei Min, Qiu Wei Yang, Xue Shen i Fang Jun Lu. "Damage Identification for Truss Structures Using Eigenvectors". Advanced Materials Research 753-755 (sierpień 2013): 2351–55. http://dx.doi.org/10.4028/www.scientific.net/amr.753-755.2351.
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This paper presents a two-stage structural damage identification method using the incomplete measured modal parameters. The first stage locates damages preliminary by using the generalized energy change of each structural element, which is defined as the inner product of the mode shape with the elemental stiffness connectivity vector. After the suspected damaged elements are determined in the first stage, the first order sensitivity of the structural eigenvector is used to identify damages more precise in the second stage. The significant advantage of the proposed method is that it is economical in computation and is simple to implement. A truss structure is analyzed as a numerical example to verify the present method. Results show that the proposed method performs well even if the measurement errors inevitably make the damage assessment more difficult. It has been shown that the presented methodology may be a promising tool to be used by research groups working on experimental damage localization.
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Evtushenko, Sergej, i Timofey Krakhmalnyy. "DEFECTS AND DAMAGES OF METAL COLUMNS OF INDUSTRIAL BUILDINGS". Construction and Architecture 9, nr 2 (2.06.2021): 11–15. http://dx.doi.org/10.29039/2308-0191-2021-9-2-11-15.
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This article is a continuation of the series of articles by the authors about the characteristic defects and damage to the building structures of industrial buildings. In earlier articles, there were descriptions of defects in ground foundations, damage to foundations, as well as arti-cles about damage to reinforced concrete columns and facades. The article presents a sys-tematization of defects and damage to metal columns of industrial buildings, based on the analysis of the results of the survey of many objects. The possible consequences of the de-velopment of the identified defects and damages are described. Recommendations for the assessment of the technical condition of damaged structures and recommendations for the elimination of identified defects and damage are given. The unique damages associated with the operation of lifting and transport equipment, road and rail transport are also given. The article concludes with an analysis of the characteristic zones of defect formation in the met-al columns of buildings for the created automated system for monitoring the state of indus-trial facilities.
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Luo, Shuai, Zhenxin Zhuang, Wei Wang i Ping Jiang. "Residual Mode Vector-Based Structural Damage Identification with First-Order Modal Information". Advances in Materials Science and Engineering 2021 (3.07.2021): 1–10. http://dx.doi.org/10.1155/2021/5526171.
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Damage identification based on the change of dynamic properties is an issue worthy of attention in structure safety assessment, nevertheless, only a small number of discontinuous members in existing structure are damaged under service condition, and the most remaining members are in good condition. According to this feather, we developed an effective damage location and situation assessment algorithm based on residual mode vector with the first mode information of targeted structure, which utilized the quantitative relationship between first natural modes of global structure with the change of the element stiffness. Firstly, the element damage location is determined with exploitation of the sparseness of element stiffness matrices based on the discontinuity of damaged members. Then, according to the distribution characteristics of the corresponding residual mode vector, the nodal equilibrium equation about the damage parameter is established based on the residual mode vector, and the damage coefficients of structural elements are evaluated with the proposed equations. Two numerical examples are given to verify the proposed algorithm. The results showed that the proposed damage identification method is consistent with the preset damage. It can even accurately identify large-degree damages. The proposed algorithm only required the first-order modal information of the target structures and held few requirements of analysis resource; hence when compared with existing methods, it has obvious advantages for structural damage identification.