Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 13 of 13 for “"damage metric"”.
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Investigation of Zinc Oxide Nanowires for Impedance Based Structural Health Monitoring
… were bonded to Al beams that were progressively damaged to determine if a change in electrical impedance could be observed to correspond to the change in structural impedance of the host beam. Changes in impedance were detected by a change in root mean squared deviation damage metric M. A …
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Implementing Impedance - Based Health Monitoring
… effects of the following three factors on damage detection abilities: actuator excitation level, test wire length and ambient conditions (temperature, structural loading and vibration). It was concluded that increasing the applied voltage improves the signal to noise ratio and damage …
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ANALYTICAL FATIGUE DAMAGE CALCULATION FOR WIND TURBINE SUPPORT STRUCTURE
… which could significantly increase the fatigue damage and possibly reduce operational design life. This research presents a practical analytical procedure of quantifying fatigue damage, investigates the impact of different foundation flexibility on fatigue life, and compares the results with …
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Qualitative health monitoring and incipient damage inspection/evaluation
… which can be implemented for real-time damage evaluation of complex structures, is investigated. The basic principle of the technique is to monitor the structure's mechanical impedance which will be changed with the presence of damage. The mechanical impedance variations are monitored by …
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Mechanics of Fiber-Controlled Behavior in Polymeric Composite Materials
Modern durability and damage tolerance predictions for composite material systems rely on accurate estimates of the local stress and material states for each of the constituents, as well as the manner in which the constituents interact. In this work, an number of approaches to estimating the stress …
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High Frequency Modeling and Experimental Analysis for Implementation of Impedance-based Structural Health Monitoring
… not typically use an analytical model for basic damage identification, a model is necessary for more advanced features of SHM, such as damage prognosis, and to evaluate system parameters when installing on various structures. A model was developed based on circuit analysis of the previously …
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Fatigue response of fabric reinforced polymeric composites
… is proposed, with internal strain energy as damage metric, to predict the useful life of FRP composites based on the experimental results. The experimental and predicted lives at various strain levels were compared (S-N curves) and the model was found to be conservative within 10% error.;Two …
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Considerations of the Impedance Method, Wave Propagation, and Wireless Systems for Structural Health Monitoring
… used for the method, the sensing area for damage detection can be very localized. Previous work has shown that wave propagation can be added to systems already equipped with hardware for impedance-based structural health monitoring. The work in this thesis shows what happens under varying …
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Development of an Energy-based Liquefaction Evaluation Procedure
… is a phenomenon that can cause tremendous damage to structures such as bridges, roads, buildings, and pipelines. The objective of this research is to develop an energy-based approach for evaluating the potential for liquefaction triggering. The current state-of-practice for the evaluation …
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Learning Structures : fusing deconvolution-based seismic interferometry with Bayesian inference for structural health assessment
… methodology for structural identification and damage detection via fusing the concepts of seismic interferometry and Bayesian inference. Firstly, a deconvolution-based seismic interferometry approach is employed to obtain the wave-forms that represent the impulse response functions (IRFs) with …
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Significance of nanosilica incorporation in type G oil well cement pastes
… penetration test (RCPT), and axial degradation/damage progression analysis and quantification after carbonic acid exposure testing. Degradation testing was performed by simulating conditions of geosequestration in a sandstone formation at a depth of roughly 1 km. These conditions were created by …
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Site reliability against anomalous behaviors
… to effectively mitigate the large-flow damage in adversarial environments. We propose three large-flow detection schemes: Exact-Outside-Ambiguity-Region Detector (EARDet), Recursive Large-Flow Detection (RLFD), and the scheme of in-Core Limiting of Egregious Flows (CLEF), which is a …
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Analysis of the sensing region of a PZT actuator-sensor
… point impedance to identify incipient level damage. The high frequency excitation provided by the PZT, ensures the detection of minor changes in the monitored structure. It also limits the sensing area to a region close to the PZT source, therefore only changes in the near field of the PZT …