Resumen en Inglés:

Abstract Storage tanks are key equipment for storing and managing liquids in industrial production. Their seismic performance evaluation is often carried out through the failure probability of vulnerability analysis. However, the vulnerability curve obtained from a single seismic component will increase the uncertainty of the evaluation, and the seismic analysis of large-capacity storage tanks has problems such as complex models and large calculations. Therefore, this paper adopts Edurance Tme Aalysis (ETA) to effectively evaluate the seismic performance of storage tanks, and verifies the effectiveness of this method by performing incremental dynamic analysis on 22 selected near-field seismic waves. Using the idea of ETA, the endurance time and seismic motion parameters are converted to derive the dynamic response of the second seismic motion parameter. Subsequently, scalar fragility curve analysis is performed for the two seismic motion parameters respectively, and then vector fragility surface analysis is performed in combination with these two parameters. The research results show that ETA can approximately determine the ultimate seismic performance of storage tanks through a single dynamic analysis, highlighting its effectiveness and efficiency in the dynamic response evaluation of storage tank structures. The surface morphology under different damage states shows a gradient change, with the surface of slight damage being the steepest and the surface of severe damage being the slowest. Compared with the scalar fragility curve, the vector fragility surface can enhance the reliability of probability and significantly reduce the uncertainty of the danger curve in structural response analysis. The fragility surface can not only be converted into a conventional fragility curve, but also complete the multi-dimensional characteristics of the seismic motion. The research results provide a more comprehensive and accurate quantitative analysis method for the evaluation of the seismic performance of liquid storage tanks.

Resumen en Inglés:

Abstract The main goal of this study is to extend the isogeometric analysis (IGA) further to investigate the free vibration of graphene platelet (GPL)-reinforced functionally graded triply periodic minimal surface (FG-TPMS) nanoplates (so-called GPLR-FG-TPMS nanoplates) embedded in Pasternak foundation (PF). The computational model includes both nonlocal elasticity and strain gradient effects to account for the impact of small-size effects inherent in nanostructures. To achieve C1-continuity condition, an IGA framework based on HSDT is developed with 7-DOFs per a control point. The motion equation of the nanoplate is derived from Hamilton's principle. The calculation program is coded in Matlab environment and verified through comparative examples. From here, the influence of geometric parameters, material properties, and boundary conditions (BCs) on the frequency of nanoplates is investigated in detail. The results obtained are reference materials for further studies as well as in the calculation and design of GPLR-FG-TPMS structures in practice.

Resumen en Inglés:

Abstract An analytical calculation methodology utilizing 3D laser scanning data is presented for the assessment of strain in smoothly dented pipelines, offering enhanced precision. This approach adopts cubic B-spline interpolation to reconstruct a smooth dent surface from preprocessed scanning point cloud data, subsequently organizing these into regular grid node coordinates via data gridding. Displacement and strain at each grid point, resulting from pipeline deformation, are determined by employing thin-shell theory alongside geometric deformation analysis. The accuracy of this method is substantiated through comparisons with results obtained from both the finite element method (FEM) and the ASME B31.8 standard. Additionally, specialized evaluation software for assessing dented pipelines has been developed, leveraging this analytical method. Comparative analysis with the finite element method reveals that the average relative errors for maximum equivalent strain on the pipeline's outer surface are 7.73% and 13.16%, respectively, underscoring the superior accuracy of the proposed method over the ASME B31.8 standard for strain calculations on the outer surface of dented pipelines.

Resumen en Inglés:

Abstract To address the issues of poor noise resistance and the lack of mechanistic analysis in the classification and diagnosis of fault vibration signals collected by sensors using existing deep learning models, this paper proposes a Transformer-based fault diagnosis model incorporating squared convolution under strong noise conditions, namely CS-Transformer. This model enhances the local feature representation of fault vibration signals through wide convolution kernels and squaring operations, improves the robustness of global features by leveraging global average pooling, and employs a single-layer Transformer encoder to uncover the correlations among global features, thereby further focusing on key fault features. Fault diagnosis experiments were conducted based on the CWRU and Paderborn bearing datasets. When the signal-to-noise ratio is -6 dB, the noise resistance of the model exceeds 91%, significantly outperforming other comparable models. This validates the superior classification performance and generalization ability of this model for bearing faults of varying degrees under strong noise conditions. Moreover, the analysis of the visualized envelope spectrum further confirms that this model can effectively enhance the target fault frequency and suppress the noise.

Resumen en Inglés:

Abstract Shaped charges, as a core technology in modern weapon systems and engineering breaching applications, achieve high-efficiency penetration through precisely controlled energy release. This capability has become critical for enhancing combat effectiveness and addressing complex engineering challenges. Based on electroforming technology, nanocrystalline copper liners were fabricated. Mechanical properties testing of the nanocrystalline copper material and penetration experiments of shaped charge jets into C45 steel targets were conducted. The Johnson-Cook constitutive model parameters applicable to nanocrystalline copper were obtained through data fitting. Numerical simulations of jet formation and penetration processes for both nanocrystalline and coarse-grained copper liners were conducted utilizing AUTODYN software. The penetration effectiveness of jets from the two types of liners was analyzed based on computational results. The study revealed that the nanocrystalline copper liner exhibits a yield strength of 250 MPa and good plasticity. Compared to the coarse-grained copper liner, the nanocrystalline copper jet demonstrated superior cohesion and continuity, achieving a 13.5% increase in average penetration depth under identical charge configurations and standoff distances. The experimental results exhibited high consistency with the simulation results, with all discrepancies remaining below 10.0%, confirming the accuracy of the fitted material parameters for nanocrystalline copper. These findings provide critical insights for further optimization of nanocrystalline copper in shaped charge design.