Готові списки джерел за темами / Dynamic damage

Добірка наукової літератури з теми "Dynamic damage"

Автор: Grafiati

Опубліковано: 7 липня 2024

Оновлено: 7 липня 2024

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Статті в журналах з теми "Dynamic damage":

Bhargav Sai, Cherukuri, and D. Mallikarjuna Reddy. "Dynamic Analysis of Faulty Rotors through Signal Processing." Applied Mechanics and Materials 852 (September 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.

Sun , Yun, Qiuwei Yang, and Xi Peng. "Structural Damage Assessment Using Multiple-Stage Dynamic Flexibility Analysis." Aerospace 9, no. 6 (May 29, 2022): 295. http://dx.doi.org/10.3390/aerospace9060295.

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Vibration-based damage assessment technology is a hot topic in aerospace engineering, civil engineering, and mechanical engineering. In this paper, a damage assessment approach using multiple-stage dynamic flexibility analysis is proposed for structural safety monitoring. The proposed method consists of three stages. The content of Stage I is to determine the number of damaged elements in the structure by the rank of dynamic flexibility change. The content of Stage II is to determine damage locations by the minimum rank of flexibility correlation matrices. Finally, the damage extents of those damaged elements are calculated in Stage III. The proposed approach fully uses the filtering ability of matrix rank analysis for data noise. A 27-bar truss structure and a steel frame structure are used as the numerical and experimental examples to demonstrate the proposed method, respectively. From the numerical and experimental results, it is found that structure damages can be successfully identified through the multiple-stage dynamic flexibility analysis. By comparative study, the proposed method has more powerful antinoise ability and higher calculation accuracy than the generalized flexibility method. The proposed method may be a promising tool for structural damage assessment.

Mahendran, G., Chandrasekaran Kesavan, and S. K. Malhotra. "Damage Detection in Laminated Composite Beams, Plates and Shells Using Dynamic Analysis." Applied Mechanics and Materials 787 (August 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.

LI, S. C., S. H. LIU, and Y. L. WU. "A NEW TYPE OF CAVITATION DAMAGE TRIGGERED BY BOUNDARY-LAYER TURBULENT PRODUCTION." Modern Physics Letters B 21, no. 20 (August 30, 2007): 1285–96. http://dx.doi.org/10.1142/s0217984907013456.

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A new type of cavitation damage has been observed on the turbines installed at the Three Gorges Power Station despite no cavitation detected during model tests. Metallurgical and fluid dynamic analysis suggests that this cavitation is triggered by boundary-layer turbulent production; the damaged (roughened) spot in turn triggers subsequent cavitation (damage) immediately down stream. This forms a sustainable dynamic process, resulting in long and equal-width streamwise damage-strips with spanwise regularity reflecting the spanwise stochastic characteristics of turbulent production. Owing to the heat effect of cavitation, intergranular corrosion takes place through sensitization process, leaving the damaged surface with a corrosion appearance. Also, bluing presents at the damaged tails, owing to the nature of low-intensity damage. Extremely large turbines are much more susceptible to this type of cavitation (damage) owing to the similarity laws currently employed for turbine development not concerning the freestream turbulence and the boundary-layer dynamics.

SILVA, R. L., L. M. TRAUTWEIN, C. S. BARBOSA, L. C. ALMEIDA, and G. H. SIQUEIRA. "Empirical method for structural damage location using dynamic analysis." Revista IBRACON de Estruturas e Materiais 13, no. 1 (February 2020): 19–31. http://dx.doi.org/10.1590/s1983-41952020000100003.

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Abstract This paper presents the use of numerical model techniques for identification and damage location adopting the Modal Curvature Difference (MCD) method as reference for the analysis of a simply supported concrete structure. Then, an empirical formulation to detect damages in this structure is proposed. In this method, called Acceleration Summation Difference (ASD), the difference of acceleration amplitude between intact and damaged structures are calculated for concrete plates simply supported on rubber bearings. During the analyses, the finite element models were developed using SAP2000® software. The results obtained depicted that it is possible to determine the approximate position of one or more damages in the structure, with some restrictions, and the proposed ASD method presented good correlation to localize the position of single or multiple damages.

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.

ZHANG, Hougui, Ruixiang SONG, Jie YANG, Dan WU, and Yingjie WANG. "Connection Damage Detection of Double Beam System under Moving Load with Genetic Algorithm." Mechanics 27, no. 1 (February 24, 2021): 80–87. http://dx.doi.org/10.5755/j02.mech.25500.

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In this paper, a novel damage detection approach for the spring connection of the double beam system using the dynamic response of the beam and genetic algorithm is presented. The double beam system is regarded as both Bernoulli-Euler beams with simply supported ends, the upper and lower beams are connected by a series of linear springs with certain intervals. With the genetic algorithm, the dynamic acceleration response of double beam system under moving load, which can be solved by the Newmark-β integration procedure, is used as the input data to detect the connection damage. Thus the dynamic response of the double beam system with a certain damage pattern can be calculated employing the moving load model. If the calculated result is quite close to the recorded response of the damaged bridge, this damage pattern will be the solution. The connection damage detection process of the proposed approach is presented herein, and its feasibility is studied from the numerical investigation with simple and multiple damages detection. It is concluded that the sophisticated damage conditions need much longer time to detect successfully.

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.

Xu, Tao, Yihang Zhu, Xiaomin Zhang, Zheyuan Wu, and Xiuqin Rao. "Dynamic Prediction Model for Initial Apple Damage." Foods 12, no. 20 (October 11, 2023): 3732. http://dx.doi.org/10.3390/foods12203732.

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Prediction models of damage severity are crucial for the damage expression of fruit. In light of issues such as the mismatch of existing models in actual damage scenarios and the failure of static models to meet research needs, this article proposes a dynamic prediction model for damage severity throughout the entire process of apple damage and studies the relationship between the initial bruise form and impact energy distribution of apple damage. From the experiments, it was found that after impact a “cell death zone” appeared in the internal pulp of the damaged part of Red Delicious apples. The reason for the appearance of the cell death zone was that the impact force propagated in the direction of the fruit kernel in the form of stress waves; the continuous action of which continuously compressed the pulp’s cell tissue. When the energy absorbed via elastic deformation reached the limit value, intercellular disadhesion of parenchyma cells at the location of the stress wave peak occurred to form cell rupture. The increase in intercellular space for the parenchyma cells near the rupture site caused a large amount of necrocytosis and, ultimately, formed the cell death zone. The depth of the cell death zone was closely related to the impact energy. The correlation coefficient r between the depth of the cell death zone and the distribution of impact energy was slightly lower at the impact height of 50 mm. As the impact height increased, the correlation coefficient r increased, approaching of value of 1. When the impact height was lower (50 mm), the correlation coefficient r had a large distribution range (from 0.421 to 0.983). As the impact height increased, the distribution range significantly decreased. The width of the cell death zone had a poor correlation with the pressure distribution on the impact surface of the apples that was not related to the impact height. In this article, the corresponding relationship between the form and impact energy distribution of the internal damaged tissues in the initial damage of Red Delicious apples was analyzed. This analysis aimed to provide a research concept and theoretical basis for more reliable research on the morphological changes in the damaged tissues of apples in the future, further improving the prediction accuracy of damage severity.

Capozucca, R., E. Magagnini, and M. V. Vecchietti. "Experimental Free Vibration of Damaged RC Beam Models." Key Engineering Materials 827 (December 2019): 499–504. http://dx.doi.org/10.4028/www.scientific.net/kem.827.499.

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Reinforced Concrete (RC) Beam undamaged and damaged were investigated by free vibration to obtain a variation of frequency values at different degree of damage. Experimental tests were carried out on RC beams in scale and in real scale. The damage of RC beams in real scale was obtained by cracking under static bending tests, while in the case of beam in scale is obtained by notches on the concrete cover with different width. In general, the effects on the dynamic response of diffused damages and of concentrated damages on a section of beam have been experimentally analyzed. The envelope of frequency response functions (FRFs) obtained by dynamic experimental tests was elaborated and the changes of natural frequency values were then correlated to the damage degree of RC beams. The experimental data have been discussed and analyzed by comparison with theoretical results.

Більше джерел

Дисертації з теми "Dynamic damage":

Djahansouzi, B. "Effect of dynamic response on impact damage." Thesis, Imperial College London, 1988. http://hdl.handle.net/10044/1/47033.

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Tappert, Peter M. "Damage identification using inductive learning." Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-05092009-040651/.

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Ge, Ma. "Structural damage detection and identification using system dynamic parameters." Related electronic resource: Current Research at SU : database of SU dissertations, recent titles available full text, 2005. http://wwwlib.umi.com/cr/syr/main.

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Quiroz, Laura Maria. "Probabilistic assessment of damage states using dynamic response parameters." Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/36955.

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To acknowledge and account for the uncertainties present in civil engineering applications is an area of major importance and of continuing research interest. This Thesis focuses on an application of Bayes' inference rule to evaluate the probability of damage in structures, using measured modal parameters and a set of possible damage states. The hypothesis is that observed changes in dynamic characteristics are due to damage accumulation over time. The main objective is to identify the most likely damage scenario from a set of previously defined damage states. These are characterized in terms of vectors, θi, the components of which are the parameters, θij, that are associated with the stiffness contribution, Kj, from each substructure undergoing damage. These stiffness matrices are uncertain as a result of random geometric and material properties. For different combinations of the damage parameters and realizations of the random variables, the modal parameters are calculated solving the basic eigenvalue problem. The results are used to calculate the statistics of the parameters given a specific damage state, the likelihood functions, as these are needed to calculate the probability of a given a set of measurements given a damage state. Each damage state Di is associated with a prior probability P(Di). In order to calculate its posterior probability, given a set of measurements, a Bayesian updating is implemented, in which the prior probability is updated by means of the likelihood functions, f(r|Di), which represent the probability density function of the modal parameter, r, given the damage state, Di. This Thesis discusses the effectiveness of the approach in identifying a particular damage state referred to as damage scenario. It is shown that measurement of multiple modal parameters is required to identify, quickly and with confidence, a given damage state. The discussion also considers the effect of error in the measurements, and the number of repeated measurements that are required to achieve a substantial confidence as to the presence of a particular damage state. Ranking of the estimated probabilities, after a set of measurements, offers guidance to the engineer as when and where to conduct a direct inspection of the structure.

Mao, Lei. "Frequency-based structural damage identification and dynamic system characterisation." Thesis, University of Edinburgh, 2012. http://hdl.handle.net/1842/7945.

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This thesis studies structural dynamic system identification in a frequency-based framework. The basic consideration stems from the fact that frequencies may generally be measured with higher accuracy than other pertinent modal data such as mode shapes; however only a limited number of frequencies may be measured in the conventional context of natural frequencies. Being able to measure extra frequencies is a key to the success of a frequency-based method. The main part of the thesis is therefore organised around the involvement of the so-called artificial boundary condition (ABC) frequencies to augment the frequency dataset for general structural damage identification. In essence, the ABC frequencies correspond to the natural frequencies of the system with additional pin supports, but may be extracted from specially configured incomplete frequency response function matrix of the original structure without the need of physically imposing the additional supports. In the first part of the research, a particular focus is placed on the actual extraction of these ABC frequencies from physical experiments through effective modal testing, data collection, data processing and analysis. The influences of key processes involved in a typical modal experimental procedure, including high-fidelity measurement of the (impact) excitation input, averaging, windowing, and an effective use of post-processing techniques, particularly the Singular Value Decomposition (SVD) technique, are scrutinised in relation to the extraction of the ABC frequencies. With appropriate implementation of testing and data processing procedures, results demonstrate that all one-pin and two-pin ABC frequencies from the first few modes can be extracted with good quality in a laboratory setting, and the accuracy of extracted ABC frequencies is comparable to natural frequencies of corresponding orders. A comprehensive study is then carried out to investigate the sensitivities of ABC frequencies to damages. Two-pin ABC frequency sensitivity is formulated by extending the expression of anti-resonance sensitivity. On this basis, the mode shape contribution is adopted as a criterion for the selection of more sensitive ABC frequencies to be employed in detailed parameter identification or finite element model updating procedures. The soundness of using ABC frequencies in structural parameter identification and the effectiveness of the above ABC frequency selection method are subsequently examined through case studies involving laboratory experiments and the corresponding FE model updating. Furthermore, a preliminary study is carried out to examine the possibility of formulating ABC frequency-based damage indicator, herein with an analogy to the mode shape curvature, for direct damage assessment. As an extended investigation in the general framework of frequency-based dynamic identification, in the last part of the thesis, a complex dynamic system, namely a railway bridge under moving loads & masses, is evaluated with regard to the various frequency characteristics involved. The variation of the natural frequencies of the bridge-moving mass system, as well as the presence of the apparent frequencies from the trainloads, are analysed in detail. Besides simplified theoretical analysis, a computational model is developed to simulate the combined bridge-moving vehicle/train system, where the vehicle mass is coupled with the bridge via surface contact. The model is verified by comparison with field measurement data and theoretical predictions. Parametric studies enable a clear identification of the correlation of the frequency contents between the response and the trainload, and provide new insight into the significance of the so-called driving and dominant frequencies. It is found that much of the dynamic response phenomena, including the resonance effect, may be explained from the view point of the frequency characteristics of the trainload pattern, which is governed primarily by the ratio between the carriage length and the bridge length. Finally, a resonance severity indicator (the Z-factor) is developed for the assessment of the resonance effect in the railway bridge response when the trainload moves at a resonance speed. Numerical results demonstrate that the proposed methods are effective for the determination of the critical speed and the resonance effects, including the situations where a significant carriage mass is incorporated.

Uwayed, Ahmed Noori. "Damage detection in laminated composite structures using dynamic analysis." Thesis, University of Leicester, 2018. http://hdl.handle.net/2381/42921.

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Laminated composite materials are used in different applications, for example mechanical, civil and aerospace structures, due to their light weight and excellent mechanical properties. However, fibre breakage and delamination are among the more serious damage that often initiate and propagate due to a number of mechanical and, specifically, dynamic loads during the operational life. Also, these damages destroy design functionality of these structures. To address this issue, damage detection is required in time to provide a good understanding of structure state in advance of any potential failure. There are a number of damage detection approaches reported in the literature and reviewed herein. Some of these are base-line free, whilst others use the intact data as a reference for the detection of damaged sections. However, currently there are a very limited number of experimental studies in the literature that use vibration-based damage detection to detect the delaminated areas, and are almost non-existent for fibre breakage; the majority of simulated studies consider delamination only. Defects in laminated structures are quite complicated and in most cases are hidden. Frequency-based damage detection is considered to be a global approach and is not useful when dealing with complex structures. There has been extensive research to develop the curvature mode shape as a reference for damage detection because it is highly sensitive at show the effects of damage. This sensitivity is tested in this research, as it is extremely difficult to detect damaged sections within composite materials, even with an active approach. Hence, the main objective of this research is to develop the curvature damage index by calculating the irregularity curvature index, and the proposal of a novel index, called the Haar index, to support the damage detection process. Both these indexes are used to detect delamination and fibre breakage on high modulus CFRP plate structures under condition of free vibration. Using these indexes gives an efficient method by which to quantify and localize damaged areas in both theoretical and experimental considerations of different lay-ups. In the modelling section, two finite element software programs, COMSOL Multiphysics 5.1 (Licence No. 7074366) and ABAQUS 6.14-1 (Licence No. 200000000008515), are used. This thesis includes development procedure of the curvature index, calculates the Haar index, gives details of the theoretical and experimental analysis, and reports the consequent results and discussion.

Lacruz, Alvarez Alfonso de. "Damage response of sandwich plates subject to dynamic loads." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/35040.

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Tondreau, Gilles. "Damage localization in civil engineering structures using dynamic strain measurements." Doctoral thesis, Universite Libre de Bruxelles, 2013. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209466.

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This thesis focuses on the development of a new method for the continuous

monitoring of civil engineering structures in order to locate small damages automatically. A

review of the very wide literature on Structural Health Monitoring (SHM) points first out that

the methods can be grouped in four categories based on their need or not of a numerical model,

as well as their need or not of information of the damaged structure to be applied. This state

of the art of the SHM methods highlights the requirement to reach each levels of SHM, which

is in particular for the localization of small damages in civil engineering structures the needs

for a non-model based output-only damage sensitive feature extraction technique. The origin of

the local sensitivity of strains to damages is also analyzed, which justifies their use for damage

localization.

A new method based on the modal filtering technique which consists in combining linearly

the sensor responses in a specific way to mimic a single degree of freedom system and which

was previously developed for damage detection is proposed. A very large network of dynamic

strain sensors is deployed on the structure and split into several independent local sensor networks.

Low computational cost and fast signal processing techniques are coupled to statistical

control charts for robust and fully automated damage localization.

The efficiency of the method is demonstrated using time-domain simulated data on a simply

supported beam and a three-dimensional bridge structure. The method is able to detect and

locate very small damages even in the presence of noise on the measurements and variability

of the baseline structure if strain sensors are used. The difficulty to locate damages from acceleration

sensors is also clearly illustrated. The most common classical methods for damage

localization are applied on the simply supported beam and the results show that the modal filtering

technique presents much better performances for an accurate localization of small damages

and is easier to automate.

An improvement of the modal filters method referred to as adaptive modal filters is next

proposed in order to enhance the ability to localize small damages, as well as to follow their

evolution through modal filters updating. Based on this study, a new damage sensitive feature

is proposed and is compared with other damage sensitive features to detect the damages with

modal filters to demonstrate its interest. These expectations are verified numerically with the

three-dimensional bridge structure, and the results show that the adaptation of the modal filters

increases the sensitivity of local filters to damages.

Experimental tests have been led first to check the feasibility of modal filters to detect damages

when they are used with accelerometers. Two case studies are considered. The first work

investigates the experimental damage detection of a small aircraft wing equipped with a network

of 15 accelerometers, one force transducer and excited with an electro-dynamic shaker. A

damage is introduced by replacing inspection panels with damaged panels. A modified version

of the modal filtering technique is applied and compared with the damage detection based principal

component analysis of FRFs as well as of transmissibilities. The three approaches succeed

in the damage detection but we illustrate the advantage of using the modal filtering algorithm as

well as of the new damage sensitive feature. The second experimental application aims at detecting

both linear and nonlinear damage scenarios using the responses of four accelerometers

installed on the three-storey frame structure previously developed and studied at Los Alamos

National Labs. In particular, modal filters are shown to be sensitive to both types of damages,

but cannot make the distinction between linear and nonlinear damages.

Finally, the new method is tested experimentally to locate damages by considering cheap

piezoelectric patches (PVDF) for dynamic strain measurements. Again, two case studies are investigated.

The first work investigates a small clamped-free steel plate equipped with 8 PVDFs sensors, and excited with a PZT patch. A small damage is introduced at different locations by

fixing a stiffener. The modal filters are applied on three local filters in order to locate damage.

Univariate control charts allow to locate automatically all the damage positions correctly.

The last experimental investigation is devoted to a 3.78m long I-steel beam equipped with 20

PVDFs sensors and excited with an electro-dynamic shaker. Again, a small stiffener is added to

mimic the effect of a small damage and five local filters are defined to locate the damage. The

damage is correctly located for several positions, and the interest of including measurements

under different environmental conditions for the baseline as well as overlapping the local filters

is illustrated.

The very nice results obtained with these first experimental applications of modal filters

based on strains show the real interest of this very low computational cost method for outputonly

non-model based automated damage localization of real structures.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished

Elbadawy, Mohamed Mohamed Zeinelabdin Mohamed. "Dynamic Strain Measurement Based Damage Identification for Structural Health Monitoring." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/86167.

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Анотація:

Structural Health Monitoring (SHM) is a non-destructive evaluation tool that assesses the functionality of structural systems that are used in the civil, mechanical and aerospace engineering practices. A much desirable objective of a SHM system is to provide a continuous monitoring service at a minimal cost with ability to identify problems even in inaccessible structural components. In this dissertation, several such approaches that utilize the measured dynamic response of structural systems are presented to detect, locate, and quantify the damages that are likely to occur in structures. In this study, the structural damage is identified as a reduction in the stiffness characteristics of the structural elements. The primary focus of this study is on the utilization of measured dynamic strains for damage identification in the framed structures which are composed of interconnected beam elements. Although linear accelerations, being more convenient to measure, are commonly used in most SHM practices, herein the strains being more sensitive to elemental damage are considered. Two different approaches are investigated and proposed to identify the structural element stiffness properties. Both approaches are mode-based, requiring first the identification of system modes from the measured strain responses followed by the identification of the element stiffness coefficients. The first approach utilizes the Eigen equation of the finite element model of the structure, while the second approach utilizes the changes caused by the damage in the structural curvature flexibilities. To reduce size of the system which is primarily determined by the number of sensors deployed for the dynamic data collection, measurement sensitivity-based sensor selection criterion is observed to be effective and thus used. The mean square values of the measurements with respect to the stiffness coefficients of the structural elements are used as the effective measures of the measurement sensitivities at different sensor locations. Numerical simulations are used to evaluate the proposed identification approaches as well as to validate the sensitivity-based optimal sensor deployment approach.
Ph. D.
All modern societies depend heavily on civil infrastructure systems such as transportation systems, power generation and transmission systems, and data communication systems for their day-to-day activities and survival. It has become extremely important that these systems are constantly watched and maintained to ensure their functionality. All these infrastructure systems utilize structural systems of different forms such as buildings, bridges, airplanes, data communication towers, etc. that carry the service and environmental loads that are imposed on them. These structural systems deteriorate over time because of natural material degradation. They can also get damaged due to excessive load demands and unknown construction deficiencies. It is necessary that condition of these structural systems is known at all times to maintain their functionality and to avoid sudden breakdowns and associated ensuing problems. This condition assessment of structural systems, now commonly known as structural health monitoring, is commonly done by visual onsite inspections manually performed at pre-decided time intervals such as on monthly and yearly basis. The length of this inspection time interval usually depends on the relative importance of the structure towards the functionality of the larger infrastructure system. This manual inspection can be highly time and resource consuming, and often ineffective in catching structural defects that are inaccessible and those that occur in between the scheduled inspection times and dates. However, the development of new sensors, new instrumentation techniques, and large data transfer and processing methods now make it possible to do this structural health monitoring on a continuous basis. The primary objective of this study is to utilize the measured dynamic or time varying strains on structural components such as beams, columns and other structural members to detect the location and level of a damage in one or more structural elements before they become serious. This detection can be done on a continuous basis by analyzing the available strain response data. This approach is expected to be especially helpful in alerting the owner of a structure by identifying the iv occurrence of a damage, if any, immediately after an unanticipated occurrence of a natural event such as a strong earthquake or a damaging wind storm.

Vongbandit, Pratip. "Morphology of surface damage resulting from static and dynamic contacts." Thesis, Brunel University, 2008. http://bura.brunel.ac.uk/handle/2438/3215.

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Contact fatigue damages resulting either from static or dynamic contact are of interest for understanding the failure modes and mechanisms leading to improvement of the components’ performances in tribological applications. The objective of this research was to ascertain how and to what extent the counterface materials, loading conditions, contact configuration, lubrication, and the environment affect the failure behaviours of material under static and dynamic contact fatigue loading. An experimental ball-on-flat test configuration was employed for both static and dynamic contact fatigue testing. In house designed test rig was used to study static cyclic loading contact fatigue behaviours of brittle polymethylmethacrylate (PMMA) in contact with balls made of different materials, i.e. Si3N4, steel, aluminium, bronze and PMMA in dry and oil-lubricated conditions. A modified four ball test machine was used to study dynamic rolling contact fatigue behaviours of thermally sprayed molybdenum and titanium coatings in contact with steel balls in dry and seawater conditions. The static contact fatigue and the dynamic contact fatigue test results revealed that counterface material, loading magnitude, lubricant and the environment play a vital role in controlling failure modes and the extent of damage. In static contact fatigue, adhesive strength of the interface was the key factor controlling damage of the PMMA plate in both dry and oil-lubricated conditions. In dry conditions, three failure modes, i.e. adhesive wear, ring cracks, and radial cracks controlled the damage of PMMA to a different degree for each combination of materials. Whereas, the damage of each combination in oil-lubricated conditions was affected by the extent of three failure modes, i.e. adhesive wear, radial cracks and abrasive wear. In dynamic contact fatigue tests, adhesive wear and inter-lamellar cracking were the major failure modes controlling damage of molybdenum coating and titanium coating in dry contact conditions while abrasive wear, corrosion and lubrication controlled damage processes in seawater conditions.

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Книги з теми "Dynamic damage":

Lambert, David Edward, Crystal L. Pasiliao, Benjamin Erzar, Benoit Revil-Baudard, and Oana Cazacu, eds. Dynamic Damage and Fragmentation. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2018. http://dx.doi.org/10.1002/9781119579311.

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Morassi, Antonino, and Fabrizio Vestroni, eds. Dynamic Methods for Damage Detection in Structures. Vienna: Springer Vienna, 2008. http://dx.doi.org/10.1007/978-3-211-78777-9.

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Antonino, Morassi, Vestroni F, and International Centre for Mechanical Sciences., eds. Dynamic methods for damage detection in structures. Wien: Springer, 2008.

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Reifsnider, K. L. Damage tolerance and durability of material systems. New York: Wiley Interscience, 2002.

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Minnetyan, Levon. Progression of damage and fracture in composites under dynamic loading. [Washington, D.C.]: National Aeronautics and Space Administration, 1990.

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China) International Conference on Damage Assessment of Structures (8th 2009 Beijing. Damage assessment of structures VIII: DAMAS 2009 : selected peer reviewed papers from the 8th International Conference on Damage Assessment of Structures (DAMAS 2009), Beijing, China, 3rd to 5th August 2009. Stafa-Zurich: Trans Tech, 2009.

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International Conference on Damage Assessment of Structures (5th 2003 Southampton, England). Damage assessment of structures: Proceedings of the 5th International Conference on Damage Assessment of Structures (DAMAS 2003), Southampton, UK, 1st to 3rd July, 2003. Edited by Dulieu-Barton J. M. Uetikon-Zuerich, Switzerland: Trans Tech Publications Ltd., 2003.

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International Conference on Damage Assessment of Structures (4th 2001 Cardiff, Wales). Damage assessment of structures: Proceedings of the 4th International Conference on Damage Assessment of Structures (DAMAS 2001), Cardiff, Wales, UK, June 25th-28th, 2001. Edited by Holford K. M. Uetikon-Zuerich, Switzerland: Trans Tech Publications Ltd., 2001.

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Sensburg, Otto K. Damage detection of aircraft structures using dynamic analysis and testing methods. Manchester: University of Manchester, 1993.

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Jozef Cornelis Walterus van Vroonhoven. Dynamic crack propagation in brittle materials: Analyses based on fracture and damage mechanics. Eindhoven: Eindhoven University of Technology, 1996.

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Частини книг з теми "Dynamic damage":

Zhang, Wohua, and Yuanqiang Cai. "Dynamic Damage Problems of Damaged Materials." In Continuum Damage Mechanics and Numerical Applications, 723–910. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-04708-4_9.

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Longère, Patrice. "Some Issues Related to the Modeling of Dynamic Shear Localization-assisted Failure." In Dynamic Damage and Fragmentation, 1–51. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2019. http://dx.doi.org/10.1002/9781119579311.ch1.

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Wautier, Antoine, Jiaying Liu, François Nicot, and Fèlix Darve. "Bifurcation Micromechanics in Granular Materials." In Dynamic Damage and Fragmentation, 315–38. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2019. http://dx.doi.org/10.1002/9781119579311.ch10.

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Nie, Xu, William F. Heard, and Bradley E. Martin. "Influence of Specimen Size on the Dynamic Response of Concrete." In Dynamic Damage and Fragmentation, 339–64. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2019. http://dx.doi.org/10.1002/9781119579311.ch11.

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Zinszner, Jean-Luc, Benjamin Erzar, and Pascal Forquin. "Shockless Characterization of Ceramics Using High-Pulsed Power Technologies." In Dynamic Damage and Fragmentation, 365–85. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2019. http://dx.doi.org/10.1002/9781119579311.ch12.

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Kumar Rai, Nirmal, and H. S. Udaykumar. "A Eulerian Level Set-based Framework for Reactive Meso-scale Analysis of Heterogeneous Energetic Materials." In Dynamic Damage and Fragmentation, 387–416. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2019. http://dx.doi.org/10.1002/9781119579311.ch13.

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Favrie, Nicolas, and Sergey Gavrilyuk. "A Well-posed Hypoelastic Model Derived From a Hyperelastic One." In Dynamic Damage and Fragmentation, 417–27. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2019. http://dx.doi.org/10.1002/9781119579311.ch14.

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El Maï, Skander, Sèbastien Mercier, and Alain Molinari. "Analysis of the Localization Process Prior to the Fragmentation of a Ring in Dynamic Expansion." In Dynamic Damage and Fragmentation, 53–93. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2019. http://dx.doi.org/10.1002/9781119579311.ch2.

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Marigo, Jean-Jacques, and Arthur Geromel Fischer. "Gradient Damage Models Coupled With Plasticity and Their Application to Dynamic Fragmentation." In Dynamic Damage and Fragmentation, 95–141. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2019. http://dx.doi.org/10.1002/9781119579311.ch3.

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Kleiser, Geremy J., Benoit Revil-Baudard, and Oana Cazacu. "Plastic Deformation of Pure Polycrystalline Molybdenum." In Dynamic Damage and Fragmentation, 143–75. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2019. http://dx.doi.org/10.1002/9781119579311.ch4.

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Тези доповідей конференцій з теми "Dynamic damage":

Blaschke, Holger, Marco Jupe, Detlev Ristau, S. Martin, S. Bock, and E. Welsch. "Dynamic absorptance behavior of hybrid multilayers at 193 nm." In Boulder Damage, edited by Gregory J. Exarhos, Arthur H. Guenther, Keith L. Lewis, M. J. Soileau, and Christopher J. Stolz. SPIE, 2002. http://dx.doi.org/10.1117/12.461688.

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Mao, Qinghua, and Xiaofeng Shen. "Dynamic Detection of Damage in Structure." In ASME 1991 Design Technical Conferences. American Society of Mechanical Engineers, 1991. http://dx.doi.org/10.1115/detc1991-0379.

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Abstract When a damage exists in a structure, the dynamic characteristics of the structure are changed. A great deal of effort has been elaborated to determine the position and the amount of the damage by using the natural frequencies and the mode shapes. In this paper, a theoretical method is given to detect the damage in a structure based on the changes of its natural frequencies and the mode shapes. After determining the location of the damage, a correcting factor describing a reduction in stiffness of damaged element gives the amount of the damage. This method is proved on two examples of beam structures.

Peng, Shuang Jiu, and J. M. Peden. "Prediction of Filtration Under Dynamic Conditions." In SPE Formation Damage Control Symposium. Society of Petroleum Engineers, 1992. http://dx.doi.org/10.2118/23824-ms.

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Taylor, Lucas N., Andrew K. Brown, Kyle D. Olson, and Joseph J. Talghader. "High-speed quantitative phase imaging of dynamic thermal deformation in laser irradiated films." In SPIE Laser Damage, edited by Gregory J. Exarhos, Vitaly E. Gruzdev, Joseph A. Menapace, Detlev Ristau, and MJ Soileau. SPIE, 2015. http://dx.doi.org/10.1117/12.2195107.

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Cheng, L., S. I. Kam, M. Delshad, and W. R. Rossen. "Simulation of Dynamic Foam-Acid Diversion Processes." In SPE European Formation Damage Conference. Society of Petroleum Engineers, 2001. http://dx.doi.org/10.2118/68916-ms.

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Grove, Brenden Michael, Jeremy P. Harvey, and Lang Zhan. "Perforation Cleanup via Dynamic Underbalance: New Understandings." In SPE European Formation Damage Conference. Society of Petroleum Engineers, 2011. http://dx.doi.org/10.2118/143997-ms.

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Liu, Xiaoguang, Wenshen Hua, and Tong Guo. "Dynamic thermal model of photovoltaic cell illuminated by laser beam." In Pacific Rim Laser Damage, edited by Jianda Shao, Takahisa Jitsuno, Wolfgang Rudolph, and Meiping Zhu. SPIE, 2015. http://dx.doi.org/10.1117/12.2187212.

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Opedal, Nils van der Tuuk, Pierre Cerasi, and Jan David Ytrehus. "Dynamic Fluid Erosion on Filter Cakes." In SPE European Formation Damage Conference & Exhibition. Society of Petroleum Engineers, 2013. http://dx.doi.org/10.2118/165107-ms.

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Yoo, David, and Jiong Tang. "Vibration-Based Structural Damage Identification Under Interval Uncertainty." In ASME 2016 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/dscc2016-9874.

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Identifying damages in mechanical structures in advance is essential part of preventing catastrophic losses. Among several non-destructive methods, the vibration-based method, which utilizes global characteristics of the structures, has several advantages such as not requiring prior information on possible damage location and physical access to it. In the meantime, the mechanical structures are inevitably subject to uncertainties, whose distribution is often unknown in practical situations due to such as limited amount of available data. Uncertainties are treated as interval uncertainty in such cases. In this regard, this study presents vibration-based damage identification under interval uncertainty. To obtain reliable result, this research does not assume any random distribution, e.g., uniform distribution, inside interval. Since detected damage is not assumed to be monotonic function with respect to interval uncertainty either, traditional fuzzy interval arithmetic is not applicable. Instead, we first carry out exhaustive search to see the effect of the interval uncertainty on the identified damage; i.e., discretizing interval uncertainty into sub-intervals and executing damage identification under all possible combinations to see the effect of the interval uncertainty on the identified damage. We then develop the unique algorithm based on M-H algorithm to facility computational efficiency.

Gasmi, Khaled, Bianca Alarcon, Monica Guerrero, and Mohamed Daoud. "Restored Productivity Using Dynamic Underbalance." In SPE European Formation Damage Conference and Exhibition. Society of Petroleum Engineers, 2015. http://dx.doi.org/10.2118/174172-ms.

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Звіти організацій з теми "Dynamic damage":

Ju, Frederick D. Structure Dynamic Theories for Damage Diagnosis. Fort Belvoir, VA: Defense Technical Information Center, October 1988. http://dx.doi.org/10.21236/ada203209.

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Chen, E. P. Nonlocal effects on dynamic damage accumulation in brittle solids. Office of Scientific and Technical Information (OSTI), December 1995. http://dx.doi.org/10.2172/176785.

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A.L. Cundy. Use of Response Surface Metamodels in Damage Identification of Dynamic Structures. Office of Scientific and Technical Information (OSTI), May 2003. http://dx.doi.org/10.2172/812182.

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Khan, Akhtar S. Dynamic and Quasi-Static Multiaxial Response of Ceramics and Constitutive/Damage Modeling. Fort Belvoir, VA: Defense Technical Information Center, January 2001. http://dx.doi.org/10.21236/ada391958.

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Zacharia, Nicole S., Ryan Davis, Xiayun Huang, and Hsiu-chin Huang. Tailoring Dynamic Mechano-Responsive Polymer Systems for Energy Dissipation and Damage Resistance. Fort Belvoir, VA: Defense Technical Information Center, November 2013. http://dx.doi.org/10.21236/ada594871.

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Ghosh, Somnath. Multi-Scale Dynamic Computational Models for Damage and Failure of Heterogeneous Materials. Fort Belvoir, VA: Defense Technical Information Center, October 2006. http://dx.doi.org/10.21236/ada459374.

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Farrar, C. R., W. E. Baker, T. M. Bell, K. M. Cone, T. W. Darling, T. A. Duffey, A. Eklund, and A. Migliori. Dynamic characterization and damage detection in the I-40 bridge over the Rio Grande. Office of Scientific and Technical Information (OSTI), June 1994. http://dx.doi.org/10.2172/10158042.

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Khan, Akhtar S. Dynamic Multi-Axial Loading Response and Constitutive/Damage Modeling of Titanium and Titanium Alloys. Fort Belvoir, VA: Defense Technical Information Center, June 2006. http://dx.doi.org/10.21236/ada455627.

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Ju, J. W. Dynamic Rate Dependent Elastoplastic Damage Modeling of Concrete Subject to Blast Loading: Formulation and Computational Aspects. Fort Belvoir, VA: Defense Technical Information Center, October 1990. http://dx.doi.org/10.21236/ada229964.

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Ko, Yu-Fu, and Jessica Gonzalez. Fiber-Based Seismic Damage and Collapse Assessment of Reinforced Concrete Single-Column Pier-Supported Bridges Using Damage Indices. Mineta Transportation Institute, August 2023. http://dx.doi.org/10.31979/mti.2023.2241.

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Near-fault earthquakes can have major effects on transportation systems due to the structural damage they impose on bridges. Therefore, it is imperative to assess the seismic damage of bridges appropriately, and this research focuses on reinforced concrete (RC) bridges. This research advances the seismic performance assessment of RC single-column pier-supported bridges with flexural failure under near-fault ground motion by use of ductility coefficients and damage indices. The methodology included modeling fiber-based nonlinear beam-column elements to simulate the damage development process of RC bridge piers under earthquake loadings, considering the global buckling of longitudinal steel bars, examining the cracking and spalling of cover concrete, and analyzing the effects of bond-slip. The tensile strain represented the damage of the longitudinal bars while the compression strain represented the cover concrete damage. Two innovative nonlinear fiber-based finite element models (FEMs) were developed: Model 1 (bond-slip excluded) and Model 2 (bond-slip included). Nonlinear static cyclic pushover analyses and nonlinear response history analyses were conducted. The simulation results were compared with available pseudo-dynamic test results. Model 1 provided a more ideal prognosis on the seismic performance of RC single-column pier-supported bridges under near-fault ground motion. The proposed damage indices can indicate the damage state at any stage and the gradual accumulation of damage in RC bridge piers, which are more convincing than most other indices in the literature. The proposed fiber-based nonlinear FEMs, together with the use of ductility coefficients and proposed damage indices, can also assist engineers and researchers in simulating the seismic behavior and assessing the damage state of RC bridge columns in a computationally effective manner which can empower engineers to identify and prioritize RC bridges for seismic retrofit and maintenance.