Line Angle Research Articles

Exploring the Path of Village Protection and Renewal Strategy Based on the Maximum Information Entropy Model in the Context of Rural Revitalisation

Abstract A comprehensive and systematic view and solution to the protection and renewal of traditional villages can help actively promote and implement the strategy of rural revitalization. This paper constructs a village protection and renewal evaluation system based on the maximum information entropy model, utilizes the entropy weight method to build the index weight evaluation matrix, and introduces the confidence factor to correct the index weights, realizing the combination of the system. Then, based on the linear weighting method to carry out a comprehensive assessment of village protection and renewal development, and based on the assessment results to formulate a personalized village protection and renewal strategy, and the feasibility analysis of the strategy with the village of T city. The results show that village protection and renewal in T city villages generally indicate an upward trend from 2016 to 2023, and the comprehensive evaluation index reached a peak of 0.3227 in 2023. In the case study, the linear regression equations fitted to the scattering points of the uptown residential area villages and the entire T city villages’ axes intersect with a difference in slopes of 14.5123. The angle of the regression line continues to increase in comparison with 2016, indicating that the role of traditional village protection planning is significant. Village protection planning plays an important role in verifying the effectiveness of the formulated village protection and renewal strategy, which can promote the development of village regional characteristics for the good.

How does the blue ring form in a blue whirl: An experimental study

This paper presents an experimental study on the flame and flow structures of the blue whirl, in pursuit of an understanding of the blue ring's formation. The flame front was identified based on the OH* chemiluminescence signal and the flow field was obtained using high-frequency particle image velocimetry (PIV). The flame and flow field reveals the presence of a radial-inward boundary layer and the corner flow lifting the blue whirl. In the case of turbulent blue whirl, a discernible recirculation zone manifests within the flame, which offers direct evidence supporting the dominance of the vortex breakdown in blue whirl's formation. Furthermore, we find that the blue whirl's cone angle approximately equals the angle of the zero-vorticity line of the flow field, whereas the height of the blue ring aligns with the height of the upward deflection point on the radial-stagnation line. These findings demonstrate a strong coupling between the flame structures and the flow field. To understand the formation mechanism of the blue ring, the flow flux across the radial-stagnation line is calculated to estimate the equivalence ratio of the mixture forming the blue ring. It reveals that the blue ring is formed where the stoichiometric reaction occurs. This happens as the corner flow induces a strong shear to facilitate the mixing within the air-fuel mixture, causing the inner layer of the mixture to be diluted to the equivalence ratio of approximately 1 at the blue ring's location.

Phenotyping of Drought-Stressed Poplar Saplings Using Exemplar-Based Data Generation and Leaf-Level Structural Analysis.

Drought stress is one of the main threats to poplar plant growth and has a negative impact on plant yield. Currently, high-throughput plant phenotyping has been widely studied as a rapid and nondestructive tool for analyzing the growth status of plants, such as water and nutrient content. In this study, a combination of computer vision and deep learning was used for drought-stressed poplar sapling phenotyping. Four varieties of poplar saplings were cultivated, and 5 different irrigation treatments were applied. Color images of the plant samples were captured for analysis. Two tasks, including leaf posture calculation and drought stress identification, were conducted. First, instance segmentation was used to extract the regions of the leaf, petiole, and midvein. A dataset augmentation method was created for reducing manual annotation costs. The horizontal angles of the fitted lines of the petiole and midvein were calculated for leaf posture digitization. Second, multitask learning models were proposed for simultaneously determining the stress level and poplar variety. The mean absolute errors of the angle calculations were 10.7° and 8.2° for the petiole and midvein, respectively. Drought stress increased the horizontal angle of leaves. Moreover, using raw images as the input, the multitask MobileNet achieved the highest accuracy (99% for variety identification and 76% for stress level classification), outperforming widely used single-task deep learning models (stress level classification accuracies of <70% on the prediction dataset). The plant phenotyping methods presented in this study could be further used for drought-stress-resistant poplar plant screening and precise irrigation decision-making.

Assessing the Impact of Mandibular Molar Root Length on Success in Supplemental Intraligamentary Injection for Irreversible Pulpitis.

This study investigates the influence of root length in mandibular molars with irreversible pulpitis on the success of supplemental intraligamentary injection following an inferior alveolar nerve (IAN) block. Various factors, including anatomical location, tooth type, and anesthetic solution, may affect supplemental anesthesia success. A total of 251 patients diagnosed with irreversible pulpitis in mandibular first or second molars underwent buccal infiltration anesthesia (4% articaine with 1:100,000 epinephrine) after IAN block injection (3% prilocaine and 0.03 IU/mL of felypressin). Fifty patients experiencing pain during access cavity preparation received supplemental intraligamentary injection (0.3 mL of 2% lidocaine with 1:80,000 epinephrine) at each mesial and distal line angle. The root length of treated teeth was recorded using an apex locator. Data analysis involved independent t-tests, Chi-square tests, and logistic regression. Successful supplemental intraligamentary injection was observed in 21 (42%) out of 50 patients. No significant correlation was found between the mean length of mesiobuccal (P=0.61), mesiolingual (P=0.34), or distal (P=0.60) canals of mandibular molars and the injection's success. Logistic regression analysis, however, revealed a significant impact of mesiolingual canal length on the success rate [OR 0.09 (0.01-0.79), P=0.030]. The root length of mandibular first and second molars does not significantly affect the success of supplemental intraligamentary injection.

Faulty feeder selection based on improved Hough transform in resonant grounded distribution networks

Due to the weak fault characteristics and inaccurate fault line selection during high impedance faults, this paper proposes a new method for fault line selection in resonant grounded distribution networks based on improved Hough transform. Firstly, the variational modal decomposition (VMD) algorithm decomposes each feeder's zero sequence power under different operating conditions, then, using Sample entropy and Pearson correlation coefficient, selects the intrinsic mode function (IMF) with the highest correlation strength with the zero-sequence power of each feeder, called IMFK. Secondly, using the Hough transform to detect IMFK, obtaining the fitted straight line and IMFK angle during the fault's initial stage. The problem of identifying the zero-sequence power mode trend is transformed into a mathematical problem of determining the geometric shapes of straight lines and curves in the zero-sequence power mode image. Finally, a line selection criterion is established by integrating correlation coefficients to identify the faulty feeder in the distribution network system when a single-phase grounding fault occurs. The PSCAD simulation and on-site measurement results show that the proposed method can ensure the effectiveness and adaptability of the line selection.

Effect of Sloping Bottom on Wave Interaction With Multiple Flexible Moored Breakwaters

Abstract An analytical framework is developed to analyze the interaction of oblique waves with multiple flexible porous breakwaters under the consideration of bottom undulation. The mathematical problem is tackled using the small amplitude water-wave theory, with Darcy’s law being applied to account for wave interaction with porous media. The bottom topography is considered to have a finite length, flanked by two semi-infinite sections of uniform bottom. The solution to the boundary value problem is approached by employing the eigenfunction expansion method within the uniform bottom regions. For the varying bottom topography, a modified mild-slope equation (MMSE) is utilized. To address the solution at the slope discontinuity at the bottom, a mass-conserving jump condition is applied. By matching solutions at the interfaces, a set of equations is derived. This system of equations encapsulates the behavior of reflection and transmission coefficients, as well as the force exerted on the breakwaters. These parameters are then investigated across various factors such as the length of the varying bottom, depth ratio, angle of the mooring line, angle of incidence, and flexural rigidity. Graphical representations of the reflection and transmission coefficients, along with the breakwater force, provide insights into the system’s behavior under different conditions. The water wave energy can be dissipated for the optimum values of flexural rigidity. The transmission coefficient is observed to be least for higher mooring angle.

Research on the Anti-Swing Control Methods of Dual-Arm Wheeled Inspection Robots for High-Voltage Transmission Lines

This paper presents an anti-swing control method to prevent situations where inspection robots detach and fall off transmission lines during obstacle crossing due to excessive swing angles caused by the rotation of the robot around the transmission line. Firstly, an obstacle-crossing model for the inspection robot was constructed and the causes of robot swinging phenomena were analyzed, in addition to their impact on obstacle crossing stability. By combining this with the obstacle-crossing model, a moment balance equation was established for the inspection robot. This equation can be used to solve mapping relationships between body offset and the tilt angle of transmission line gripping arms. We propose an anti-swing control strategy by adjusting the angle of the transmission line gripping arm’s pitching joint to make the body offset approach zero, and by utilizing the advantages of fuzzy logic in the fuzzy PID algorithm compared with the traditional PID algorithm, it can adaptively avoid the occurrence of robot swinging phenomena. The experimental results of obstacle-crossing experiments under no wind and wind turbulence conditions indicated that the proposed anti-swing control method in this study can effectively keep the body offset to within 3 mm. Compared with the methods of not using anti-swing control and using traditional PID anti-swing control, in the absence of wind effects, the peak values of body offset were reduced by 96.53% and 18.85%, respectively. Under the influence of wind turbulence, the peak values of body offset were reduced by 97.02% and 27.12%, respectively. The effectiveness of the anti-swing control method proposed in this paper has thus been verified.

Biomechanical insights into ankle instability: a finite element analysis of posterior malleolus fractures

BackgroundPosterior malleolus fractures are known to be associated with ankle instability. The complexities involved in obtaining precise laboratory-based spatial pressure measurements of the ankle highlight the significance of exploring the biomechanical implications of these fractures.MethodsFinite element analysis was utilized to examine the stress distribution across the contact surface of the ankle joint, both in its natural state and under varied sagittal fracture line angles. The study aimed to identify stress concentration zones and understand the influence of sagittal angles on stress distribution.ResultsThree distinct stress concentration zones were identified on the ankle's contact surface: the anterolateral tibia, the anteromedial tibia, and the fracture line. The most significant stress was observed at the fracture line when a fracture occurs. Stress at the fracture line notably spikes as the sagittal angle decreases, which can potentially compromise ankle stability. Larger sagittal angles exhibited only minor stress variations at the contact surface's three vertices. It was inferred that sagittal angles below 60° might pose risks to ankle stability.ConclusionsThe research underscores the potential implications of fractures on the stress profile of the ankle joint, emphasizing the role of the contact surface in ensuring stability. The identification of three zones of stress concentration and the influence of sagittal angles on stress distribution offers a valuable reference for therapeutic decision-making. Further, the study reinforces the importance of evaluating sagittal fracture angles, suggesting that angles below 60° may compromise ankle stability.

CT measurement of damage characteristics of meso-structure of freeze-thawed granite in cold regions and preliminary exploration of its mechanical behavior during a single freeze-thaw process

Abstract The freeze-thaw (FT) damage characteristics of granite after different FT cycles were studied using computed tomography (CT) images. The three-dimensional (3D) volume numbers in the image were extracted to obtain the 3D pore structure of representative volume elements (RVEs) of granite under different FT cycles. The CT images of granite after 80 FT cycles were selected to draw reference lines for quantitative analysis of the distribution of meso-cracks in granite after FT cycles. Subsequently, a finite element model was established to explore the mechanical properties of minerals in granite during a single FT process. The results show that the FT damage inside the granite exhibits fracture characteristics, and the number of internal cracks, cracks area, and voxel porosity increase with the increase of FT cycles. After 80 FT cycles, the distribution of meso-cracks on the cross-section of granite exhibits significant anisotropy, and the distribution density and variation coefficient of meso-cracks vary with the dip direction angle of the reference line. The maximum principal stress and strain in the finite element model are negatively related to temperature. The maximum principal stress and strain of biotite minerals are consistently higher than those of feldspar and mica during FT cycles. The results can provide a reference for exploring the internal mechanism of the weakening of mechanical properties of granite microstructure caused by FT damage in cold regions.

Impact of marginal defects on the accuracy of automated finish line detection in tooth preparation.

The present study aimed to evaluate the accuracy of automated detection of preparation finish lines in teeth with defective margins. An extracted first molar was prepared for a full veneer crown, and marginal defects were created and scanned (discontinuity of finish line: 0.5, 1.0, and 1.5 mm; additional line angle: connected, partially connected, and disconnected). Six virtual defect models were entered into CAD software and the preparation finish line was designated by 20 clinicians (CAD-experienced group: n = 10; CAD-inexperienced group: n = 10) using the automated finish line detection method. The accuracy of automatic detection was evaluated by calculating the 3D deviation of the registered finish line. The Kruskal-Wallis and Mann-Whitney U tests were used for between-group comparisons (α = 0.05). The deviation values of the registered finish lines were significantly different according to conditions with different amounts of finish line discontinuity (P < 0.001). There was no statistical difference in the deviation of the registered finish line between models with additional line angles around the margin. Moreover, no statistical difference was found in the results between CAD-experienced and CAD-inexperienced operators. The accuracy of automated finish line detection for tooth preparation can differ when the finish line is discontinuous. The presence of an additional line angle around the preparation margin and prior experience in dental CAD software do not affect the accuracy of automated finish line detection.

Geometry of the LMC based on multiphase analysis of multiwavelength Cepheid light curves using OGLE-IV and Gaia DR3 data

ABSTRACT The period–luminosity (PL) relation of Cepheids in the Large Magellanic Cloud (LMC) plays a pivotal role in extragalactic distance measurement and the determination of the Hubble constant (H0). In this work, we probe the geometry of the LMC through a detailed study of multiphase PL relations of these Cepheids, leveraging data from the OGLE-IV and Gaia DR3 data bases. We analyse the light curves of a combined sample of ∼3300 fundamental (FU) and first overtone (FO) mode classical Cepheids. We obtain multiphase data with 50 phase points over a complete pulsation cycle from the OGLE (V, I) and Gaia (G, GBP, GRP) photometric bands. We determine the distance modulus and reddening values of individual Cepheids by fitting a simultaneous reddening law to the apparent distance modulus values. We calculate the LMC viewing angle parameters: the inclination angle (i) and position angle of line of nodes (θlon) by fitting a plane of the form z = f(x, y) to the three-dimensional distribution of Cepheids in Cartesian coordinates $(x, y, z)$. The values of LMC viewing angles from multiphase PL relations are found to be: i = 22.°87 ± 0.°43 (stat.) ± 0.°53 (syst.), θlon = 154.°76 ± 1.°16 (stat.) ± 1.°01 (syst.), respectively. The use of multiphase PL relations in multiple bands results in lower uncertainties for the LMC viewing angle parameters as compared to those derived from the mean-light PL relations. This shows that the use of multiphase PL relations with multiwavelength photometry significantly improves the precision of these measurements, allowing better constraints on the morphology and the structure of the LMC.

Mechanical Properties of Buried Steel Pipe With Polyurethane Isolation Layer Under Strike-Slip Fault

Abstract Long-distance buried pipelines are one of the most common and economical transportation methods for oil and gas, but the fault movement will pose a threat to the safety of pipelines. The main challenge of pipeline under strike-slip faults is to improve the ability of resistance to fault dislocation, and the main aim of the study is how to improve the critical fault displacement of pipelines with the help of polyurethane isolation layer. Three-dimensional finite element models were proposed for mechanical analysis of X80 buried steel pipe with polyurethane isolation layer under strike-slip fault. The influence of factors on the mechanical properties of pipelines were studied, such as thickness of isolation layer, internal pressure, fault displacement, diameter-thickness ratio, and the angle of pipe and fault line. The simulation results indicate that with the increase of the thickness of the isolation layer, the development of the maximum tensile and compressive strain of the pipeline is significantly reduced for the same fault displacement, resulting in a significant increase in the critical fault displacement corresponding to the three failure modes of the pipeline. As the ratio of diameter to thickness and internal pressure decrease, the critical displacements decrease. When designing and planning the pipeline, pipeline is recommended with the seismic isolation layer, large wall thickness, and the crossing-angle at 70 deg∼80 deg. The research provided a reference for judgment of earthquake resistance, failure analysis, and safety design of pipelines with polyurethane isolation layer crossing strike-slip faults.

Research on Measurement of Multi-beam Transducer Based on Analytic Geometry Method

The ocean is inseparable from the survival and development of human beings. It not only provides rich resources for human beings, but also provides a large number of samples for human scientific research. For the efficient development of the ocean, detailed and accurate seabed topography and geomorphology information is needed as a prerequisite. In this paper, aiming at the problem of multi-beam detection system detecting full coverage water depth strip in waterway, the measurement model of multi-beam transducer under different survey lines is established. Based on the combination of numbers and shapes, firstly, this paper considering the special situation that the survey line is perpendicular to the horizontal component of the normal of the seabed slope, it is concluded that the depth of seawater is positively correlated with the width of the survey line. Secondly, when the angle of the survey line is arbitrary, and the spatial rectangular coordinate system model is established, this paper considering the law of the width of the survey line at different angles and distances. Finally, through analytic geometry method, the measuring line equations at different positions and angles are expressed in this paper, and the measuring line width is quantified according to the distance formula between two points. The results show that the coverage width is unchanged at the center of the sea area or when the direction of the survey line is perpendicular to the horizontal component of the normal of the submarine slope. The coverage width is symmetrically distributed at the survey line angle. The results show that the multi-beam transducer measurement model is effective.

The differential conjugate hemisphere ionospheric response during solstice storms and the winter side maxima

The hemispheric differences in the impact of the geomagnetic storms of June 2015 and December 2015 are investigated. A meridional chain of ground observatories along 95°E ± 10°E (conjugate point-GNSS receiver/Ionosonde), satellite in-situ measurements (SWARM/COSMIC/C-NOFS), and Total Electron Content maps are utilized. Symmetric negative (positive) effects were noted during the main phase of the June (December) storm but hemispheric asymmetry was manifested during the recovery phase. The quiet time hemispheric asymmetry was reversed during both storms with positive TEC effects on the winter side. Differential VTEC and NmF2 responses exhibited seasonal variation. On 23 June 2015, the VTEC enhancements in the southern low latitude were large and consistent in contrast to the weak response in NmF2. In contrast, during the December storm, the NmF2 depletion in southern low latitude was more severe than the corresponding depletion in VTEC. The topside density/TEC enhancement in the southern low latitude recorded by SWARM was much higher than 300 % during the morning of 23 June. The SWARM Ne/TEC profile as well as the ground GPS TEC map showed a third latitudinal maximum around −45° dip angle of field lines in southern low latitudes on 23 June, in addition to the conventional EIA crests. Similarly, an early morning maximum was recorded at + 45° dip (northern hemisphere) on 21 December. The hmF2 measured by the southern hemisphere ionosonde and COSMIC satellite showed an anomalously higher altitude of the F2-layer on 23 June while C/NOFS recorded equator-ward meridional flow velocity. The reversal of the hemispheric asymmetry and the additional storm time transient maximum on the winter side is attributed to the equator-ward winds surge in the winter hemisphere due to storm time heating of the polar region.

United composite strength calculation method for special-shaped CFST columns with multiple cavities

The present study investigates the method of calculating the composite strength of special-shaped concrete-filled steel tube (CFST) members with multiple cavities. Based on the research findings of CFST unified theory and some tests, a quantitative method to evaluate the concrete constraint effect is proposed for cross-sectional shapes ranging from regular triangles, squares…regular octagons to circles. The cross-sectional composite strength of regular polygonal CFST members is determined by the way dividing the concrete into effective and ineffective constraint regions, discounting constraint coefficients, and applying unified formulas. Additionally, a regression analysis is conducted to establish the relationship between interior angles and constraint effects. Subsequently, using quadrangle CFSTs as an example, this study investigates the relationship between cross-sectional regularity and constraint effect, and proposes a composite strength calculation method related to it. Finally, the special-shaped multi cavity cross section is separated into several simple polygonal cross sections, taking into account shape efficiency and regularity, to calculate the composite strength of each cavity CFST member and summarize them for determining the total axial compressive bearing capacity. The research findings indicate that a linear relationship exists between the interior angle of the cross section and the initial tangent line angle of the second-degree curve, which serves as the boundary between effective and ineffective constraint regions in regular polygonal steel tube confined concrete. The proposed unified composite strength calculation method, specifically designed for special-shaped CFST columns with multiple cavities, can accurately predict their actual strength.

Dynamic hybrid observer-based early slipping fault detection for high-speed train wheelsets

Early slipping fault detection of High-speed Train (HST) wheelsets on ramped railway lines has been a challenging problem due to the difficulty of achieving accurate detection in a limited time-frame. A dynamic hybrid observer-based early slipping fault detection strategy is proposed. Firstly, a hybrid observer-based adhesion coefficient estimation method is proposed. The hybrid observer is constructed in an interconnected configuration, which integrates the estimated ramped line angle into the adhesion coefficient estimation. Then, a multivariate evaluation function (MEF)-based parameter dynamic adjustment method is proposed. The MEF is constructed to reconcile the trade-off of the speediness and smoothness of the hybrid observer. Finally, a dynamic adhesion coefficient-based early slipping fault detection method for HST wheelsets is proposed. And the proposed strategy is verified on the hardware-in-the-loop(HIL)-based platform. The test results show that the proposed strategy can actualize millisecond-level early slipping fault detection and reduce the false detection rate on ramped railway lines.

Gender Dimorphism of Skeletal Measurements and Dental Angle Classification in Orthodontic Patients.

The present study aimed to evaluate gender dimorphism of the skeletal and dental angles and measurements among different types of malocclusions in the Population of Jizan, Kingdom of Saudi Arabia (KSA). Cephalometric data were retrieved from the archived records of 272 dental patients, comprising 134 males and 138 females. Skeletal and dental malocclusions in both the sub-groups were digitally studied. The measurement reliability was assessed using the intra-class correlation coefficient (ICC). Non-parametric Mann-Whitney U tests were performed to evaluate the difference in skeletal and dental parameters between genders. The Chi-square test was done to determine the difference in malocclusion patterns amongst the gender. Statistical significance was noted in dental malocclusion (p-value = 0.003) and facial height, with females having a steeper mandible plan than males. The Sella-nasion-Nasion-Vertical line angles were reported high in females with no statistical significance. Linear cephalometric values were measured higher in males than females, whereas angular values and facial height parameters were lower in females than male. Within the limitation of this study, it could be concluded that there is a prominent difference measured in facial profiles of males and females with higher facial height in males. Clinical significance and limitations: These clinical outcomes will help orthodontists to analyze the accurate base angles and points to draft proper treatment plans considering the variation in the profile of males and females.

Fault line selection algorithm for distribution networks based on AdapGL‐GIN network

AbstractWhen a grounding fault occurs in the distribution network with distributed generation, the network topology becomes intricate, making it challenging to extract fault characteristics, resulting in a decrease in the precision of fault discrimination. To address this issue, a graph isomorphism network (GIN) approach based on the parameterized adaptive graph learning (AdapGL) module is proposed, transforming the distribution network fault selection problem into a graph classification task. First, the adjacency matrix of the distribution network's topology graph is initialized. This matrix, combined with feature vectors from the robust local mean decomposition energy entropy and transient dielectric loss angle of line, will be input into the GIN. Then, the AdapGL module is integrated into the GIN, dynamically learning and updating the one‐way relationships between actual network nodes to complete the graph classification task. Finally, a radial distribution network model (RDNM) and an improved IEEE 34 nodes model are established, and the fault selection results of the AdapGL‐GIN method are compared with those of other methods. The results indicate that the proposed method achieves higher accuracy than other methods, demonstrating significant practical importance in engineering applications.

What is the stable internal fixation for the unstable and osteoporotic supracondylar femoral fractures: a finite element analysis

BackgroundOsteoporotic supracondylar femoral fractures (OSFF) have historically been managed by the lateral anatomical locking plate with reasonable success. However, for some kinds of unstable and osteoporotic supracondylar femoral fractures (UOSFF), especially with bone defects, unilateral locking plate (ULLP) fixation failed or resulted in implant breakage. This paper is going to explore what is the stable internal fixation for UOSFF by adding the bilateral locking plate (BLLP) fixation.MethodsOSFF models were divided into two groups according to the fracture line type, which would be further subdivided according to their angle of fracture line, presence of bone defect, location, and degree of bone defect. Thereafter, kinds of locking plate fixation were constructed. A 2010-N load was applied to the femoral head, and a 1086-N load was applied to the greater trochanter. In this condition, the maximum von Mises stress distribution of models were investigated.ResultsFirstly, it was obviously found that the stress concentration in the BLLP group was more dispersed than that in the ULLP group. Secondly, according to the fracture line analysis, the stress value of fracture line type in “\\” model group was higher than that of “/” model group. Moreover, with the increase in fracture line angle, the stress value of the model increased. Thirdly, from the bone defect analysis, the stress value of the medial bone defect (MBD) model group was higher than that of the lateral bone defect (LBD) model group. And as the degree of bone defect increased, the stress value increased gradually in the model group.ConclusionIn the following four cases, lateral unilateral locking plate fixation cannot effectively stabilize the fracture end, and double locking plate internal fixation is a necessary choice. First, when the angle of the fracture line is large (30, 45). Second, when the fracture line type is “/.” Third, when the bone defect is large. Fourth, when the bone defect is medial.

Dynamic transient analysis of a submerged floating tunnel under impact loading

A submerged floating tunnel (SFT) is an innovative structure constructed in the deep sea that connects continents or continents and islands. Submarines, underwater vehicles, and marine life may infrequently collide with an SFT, causing damage or interfering with the operation of the SFT. In this study, collision tests were conducted. To analyze the dynamic transient response of the SFT, the impact load was varied using different velocities and masses; a total of 288 impact tests were performed by adjusting the impact location (top, middle, and bottom) and the type of mooring line. The largest displacement occurred when the impact location was at the top of the SFT. The stability of the SFT was examined by installing four types of mooring lines. The presence of the central support line suppressed the displacement of the SFT, and as the installation angle of the mooring lines decreased, the behavior of the SFT stabilized. The impact force of the SFT was linearly correlated with the velocity and proportional to the square root of the mass of the impactor. The results of this study can be used to identify the vulnerable locations on the SFT that require meticulous monitoring to ensure safety.