In order to solve the problem that the wide range of damage monitoring for large-scale structures, a triangular sparsearray-based damage monitoring is researched and validated in this paper. The typical Lamb wave str...
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(纸本)9789881563804
In order to solve the problem that the wide range of damage monitoring for large-scale structures, a triangular sparsearray-based damage monitoring is researched and validated in this paper. The typical Lamb wave structural responses is analyzed firstly. Multi characteristic parameters is extracted from the responses based on the varies of the response due to the damage. Using these multi characteristic parameters, the damage location in large-scale structure can be monitored by the damage identification model which is designed by using SVM (Support Vector Machine). Experimental validation shown that the multi characteristic parameters from triangular sparsearray layout can be used to identify the specific orientation of damage in relative large-scale structure, and the trained SVM based damage identification model can also reveal the damage ***, the existing large-scale structural damage monitoring method is improved.
During aircraft operations, the impact events experienced by the aircraft may cause damage to the structure, thus posing a safety hazard. Therefore, an accurate determination of where the impact occurred and the time ...
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During aircraft operations, the impact events experienced by the aircraft may cause damage to the structure, thus posing a safety hazard. Therefore, an accurate determination of where the impact occurred and the time history of the impact force can provide an important basis for assessing the condition of the aircraft. However, modern aircraft structures are often large and complex, and relying on dense arrays of sensors for monitoring adds additional weight to the aircraft and reduces the economics of aircraft operation. This paper proposes a region-topoint monitoring strategy. First, a Convolutional Neural Network (CNN) model with region localization capability is trained using the sparse sensor array acquisition data. Then, the weighted center algorithm is used to determine the specific location where the impact occurs, in which the added fuzzy genetic algorithm can provide the ability to adjust weights to improve localization accuracy adaptively. As for the impact force prediction, this paper adopts a model based on a Convolutional Neural Network-Gated Recurrent Unit combined with a SqueezeExcitation attention mechanism (CNN-GRU-SE), which is capable of predicting the impact force occurring in the flat plate and reinforced structure region of the aircraft under different energy conditions. Finally, the impact of incorporating a transfer learning approach on model performance and training cost is investigated for fuselage regions with different structures.
In order to solve the problem that the wide range of damage monitoring for large-scale structures,a triangular sparsearray-based damage monitoring is researched and validated in this *** typical Lamb wave structural ...
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In order to solve the problem that the wide range of damage monitoring for large-scale structures,a triangular sparsearray-based damage monitoring is researched and validated in this *** typical Lamb wave structural responses is analyzed *** characteristic parameters is extracted from the responses based on the varies of the response due to the *** these multi characteristic parameters,the damage location in large-scale structure can be monitored by the damage identification model which is designed by using SVM(Support Vector Machine).Experimental validation shown that the multi characteristic parameters from triangular sparsearray layout can be used to identify the specific orientation of damage in relative large-scale structure,and the trained SVM based damage identification model can also reveal the damage ***,the existing large-scale structural damage monitoring method is improved.
Damage detection techniques using Lamb waves have shown excellent capabilities in the diagnosis of composite structures. However, structural health monitoring of composite structures is challenging, especially for dam...
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Damage detection techniques using Lamb waves have shown excellent capabilities in the diagnosis of composite structures. However, structural health monitoring of composite structures is challenging, especially for damage classification. This study proposes a machine learning-based method with a sparse sensor array to achieve quantitative classification of the damage location and severity on a composite plate. First, multi features extraction is used to construct a support vector machine (SVM) damage localization model. Second, optimal path extraction combined with principal component analysis (PCA) is used to construct an SVM model for classifi-cation. To reduce the operational burden of structures, the sparsearray is employed. To improve the damage classification accuracy, Fisher clustering is proposed to extract the optimal detection path. Then, PCA is used to achieve data fusion. Experimental results on a glass fiber-reinforced epoxy composite laminate plate demonstrate that the proposed technique can accurately locate and classify the quantitative artificial damage.
Due to the development of new materials and advanced manufacturing technologies, the application of largescale composite structures has become increasingly widespread. Ensuring the safe and stable operation of such st...
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Due to the development of new materials and advanced manufacturing technologies, the application of largescale composite structures has become increasingly widespread. Ensuring the safe and stable operation of such structures presents new challenges across various application domains. Addressing the limitations of existing guided wave structural health monitoring methods for online damage monitoring in large-scale structures, such as cumbersome equipment setup, insufficient signals coverage, and difficulties in processing massive data, a method for sub-area collaborative guided-wave-based structural damage monitoring and severity assessment based on sparse sensing is proposed. By employing a sparse sensing array layout, the structure is divided into multiple monitoring sub-areas with arranged sensing arrays to reduce overall complexity. The characteristic responses of the guided wave signals from different sub-areas are extracted to construct feature sub-spaces. Support vector machines are adopted to construct evaluation sub-networks in each feature sub-space, enabling regional monitoring. Additionally, an improved D-S evidence fusion algorithm is applied to fuse the decision-layer inputs from each evaluation sub-network, effectively utilizing the feature information from multiple sub-areas and enhancing the accuracy of damage severity assessment for large-scale structures. Experimental results on typical composite structure specimens demonstrate that by fusing the support vector machine evaluation results from each sub-area, the accuracy of damage severity assessment reaches 97.5%, with uncertainties in the severity assessment below 5%.
Impact events may cause some damage to aerospace composite structures that are difficult to inspect on the surface, thus threatening the operational safety of the aircraft. Therefore, estimating the impact location an...
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Impact events may cause some damage to aerospace composite structures that are difficult to inspect on the surface, thus threatening the operational safety of the aircraft. Therefore, estimating the impact location and the original impact force is necessary. This paper proposes a deep-learning model for impact monitoring based on feature extraction. The first step employs a convolutional neural network to localize the impact region, initially narrowing it to a specific area and then determining a precise location using a weighted center algorithm. In the second part, the temporal convolutional network is first utilized for feature extraction, and then the gated recurrent unit is used for impact force estimation. During the training of the impact monitoring model, a domain-adversarial transfer learning strategy is employed to extract domain-invariant features between the source and target domains, reducing the data needed for training. This method can monitor impacts on large, complex composite structures using sparse sensor arrays.
The lithography immersion flow field is highly sensitive to minor variations due to the precision demands of lithography. The scanning flow induces pressure fluctuations on the lens surface, subsequently impacting the...
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The lithography immersion flow field is highly sensitive to minor variations due to the precision demands of lithography. The scanning flow induces pressure fluctuations on the lens surface, subsequently impacting the quality of exposure. Previous measurement methods have encountered sparse distribution measurements on the lens surface due to limitations in sensor size and flow field dimensions. In this manuscript, the authors propose a modal fusion flow field reconstruction method, effectively integrating sensor-based experimental methods and equation-based computational methods. This method achieves high-resolution measurements of stress distribution and velocity distribution. Initially, a simulation of the flow field under operational conditions is conducted to acquire a dataset, followed by decomposing the dataset into modes to establish a modal library. Throughout the measurement process, the modal library is dynamically restructured based on sensor signal using a sparse representation method to forecast the flow field, and subsequently, the flow field is corrected in accordance with the Navier-Stokes equation.
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