Search Results (217)

The bi-cable system enhances the vertical stiffness of the middle pylon, enabling the use of a traditional pylon in multi-pylon suspension bridges. However, research on multi-pylon suspension bridges utilizing a bi-cable system remains in its early stages, with parameter analysis still being limited. The benefits of bi-cable systems in long-span three-tower suspension bridge configurations remain unclear. This paper presents an analysis of three-tower suspension bridges with spans ranging from 1500 to 2500 m, using a simplified calculation method for a bi-cable system and incorporating the elastic deformation of hangers. The effects of the top cable load distribution factor, tower stiffness, sag-to-span ratio, and side-to-main span ratio on static performance are examined, and reasonable value ranges for each parameter are proposed. Full article

This paper investigates the effects of two control measures on vortex-induced vibration and wake-induced vibration of suspension bridge cables through wind tunnel experiments. For a single cable, a passive suction/jet ring arrangement is proposed, and its vortex-induced vibration suppression performance under different density configurations (single-segment and two-segment dense arrangements) is analyzed. Experiments show that the total length of the ring is positively correlated with the control effect. The two-segment arrangement is significantly better than the single-segment arrangement when the total length is 1/4 of the cable length, with a maximum reduction in vibration displacement of 88%. For double cables, a spacer with an integrated tuned mass damper (TMD) is used. The results show that the TMD can effectively suppress vortex-induced vibration and wake-induced vibration. Its control effect depends on the installation position and the damper’s natural frequency. Installation at mid-span and 1/4-span positions can significantly reduce the vibration response, especially for suppressing first-order mode vibration. This study provides an optimized aerodynamic and damper combination scheme for cable wind vibration control. Full article

This article examines the transcultural and transmedial transformation of the kalavinka motif along the Silk Road, situating its development within the interpretive framework of the Indian kinnara/kinnarītradition. It asks how a figure associated with wondrous sound and devotional praise in Buddhist cosmology came to function as a wearable ornament without losing its religious identity. Through close formal analysis of Dunhuang murals from the Tang period (618–907 CE), the study identifies three interrelated visual processes that prepared the motif for mobility across media: the fusion of gendered pairs into an androgynous form, the progressive elongation and ornamental stylization of the tail, and the reorientation of bodily pose into compact, suspension-friendly configurations. These mechanisms are then examined in relation to eleventh-century painted and excavated materials, including donor adornment in Western Thousand Buddha Cave 16, a Khara Khoto scroll, a Liao (916–1125 CE) gold kalavinka earring, and a Western Xia linked-pearl headdress. Comparative visual and material analysis shows that kalavinka imagery circulated in parallel across mural, painted, and metal media, where scale, material, and bodily placement re-coded rather than erased its sacred associations. The study argues that this process is best understood as material translation, and it proposes a model for linking formal change, sensory affordance, and religious function in the arts of the Silk Road. Full article

Accurate prediction of aggregation in suspensions is crucial for diverse engineering applications. This paper develops a sequential theoretical strategy, based on tunnel theory, to predict the aggregation configuration in magnetic compound fluids (MCF) by evaluating their volume concentration C_v. We formulated the viscosity η, resistance R, and capacitance C resulting from aggregation as functions of C_v. This involved a theoretical procedure using tunnel theory, refined using experimental data, including vertical force F_v arising from the concentration gradient, as well as electrical conductivity σ and permittivity ε. The theoretical formulation for η was further refined by considering hypothetical aggregation configurations, specifically non-uniform particle distribution and agglomerations approximated as spheroids with axis ratio κ, along with experimental data on shear flow. For R and C, the formulations were refined using experimental data for σ and ε, together with the relationship between C_v and the applied magnetic field H_v derived from tunnel theory and F_v. This sequential theoretical analysis yielded final formulations for η, R, and C as functions of H_v and initial volume concentration C_v,o. Specifically, η was expressed as a function of κ and C_v,o for the shear and stress–shear strain γ’ relationship under conditions of H_v < 200 mT, 11 < C_v,o < 30 vol.%, and γ’ < 300 1/s. R and C were determined under conditions of H_v < 150 mT and 11 < C_v,o < 30 vol.%. These findings pave the way for novel theoretical predictions of C_v, R, and C based solely on H_v data, a capability crucial for designing diverse materials. Full article

To enhance the energy efficiency of data center cooling systems, this study introduces Micro-encapsulated Phase Change Material Suspension (MPCMS) into a naturally stratified cold storage system. Leveraging its superior properties, including high latent heat, high specific heat, and excellent fluidity, a three-dimensional transient numerical model was developed to investigate the thermal stratification characteristics during the discharging process. The analysis focuses on the impacts of operational conditions (flow rate and mass fraction) alongside key tank structural parameters (height-to-diameter ratio, uniform flow plate perforation rate, installation position, and aperture). The results indicate that the thermal stratification performance of MPCMS is significantly superior to that of water. Specifically, during the middle discharge stage (t* = 0.4) at a high flow rate of 12.56 m³/h, the thermocline thickness of MPCMS-10 wt% is restricted to only 245 mm, representing a 93.82% reduction compared to 3964 mm for water. Furthermore, at the initial discharge stage (t* = 0.05), the thermocline thickness decreases significantly with increasing MPCMS mass fraction; as the mass fraction rises from 10 wt% to 30 wt%, the thickness sharply drops from 421 mm to 120 mm (a 71.44% reduction), and the stratification number (Str) reaches an optimal 1.00. In terms of macroscopic structural optimization, a height-to-diameter (H/D) ratio between 2 and 4 provides the best balance of stratification stability and cold storage efficiency. Mechanistically, integrating a uniform flow plate effectively suppresses thermal jet disturbances. During the initial discharge stage, a plate with a 10% perforation ratio reduces the thermocline thickness by 69.12% (from 421 mm to 130 mm) relative to the no-plate baseline. The optimal flow plate configuration was identified as a 10% perforation rate, a 20 mm aperture, and an installation spacing of 1.25% of the tank height. Ultimately, this study validates the substantial potential of MPCMS through robust quantitative data, providing a solid theoretical foundation and precise design guidelines for high-efficiency cold storage systems. Full article

This paper investigates the performance of a speed-dependent variable inerter in improving vehicle suspension performance. Unlike conventional and passive inerter suspensions with fixed mechanical properties, the proposed speed-dependent variable inerter allows continuous adjustment of inertance according to the relative acceleration between the sprung and unsprung masses, enabling variable inertance under changing driving speeds and road conditions. A quarter-vehicle model is employed to evaluate a conventional passive inerter and both a linearly and non-linearly increasing variable inerter system in series and parallel layouts. A multi-objective genetic algorithm simultaneously optimizes the suspension damping and variable inertance range with respect to ride comfort and road-holding ability. To further validate the simulations, the optimized systems are evaluated under step, random and sinusoidal road profiles. The results showed that a linearly increasing variable inerter, particularly in parallel configuration, offers the best compromise between ride comfort and road holding, achieving up to 4.94% improvement in ride comfort under a random road profile, outperforming conventional passive inerter and non-linearly increasing inerter suspensions, while maintaining acceptable tire–road contact. Performance improvements under step and sinusoidal road profiles were moderate, while more significant performance gains were observed under a random road profile due to the larger acceleration change induced, which led to larger inertance variation. These findings confirmed the potential of variable inerters as an alternative approach to vehicle suspension systems, due to their passive implementation, absence of control requirement and compatibility with compact suspension architectures. Full article

Return-type cable suspension bridges transfer the main-cable force to the anchorage predominantly in the horizontal direction, which may induce coupled sliding–overturning instability of the anchorage–foundation system. This study examines the stability of return-type cable gravity anchorage using the composite anchorage of the Jixin Expressway Yellow River Three Gorges Bridge as the prototype. A 1:100 laboratory specimen was designed based on similarity theory and tested under incremental loading until failure. Four configurations were considered by combining two embedment ratios (1/4 and 1/2) with two base types (flat-base and shear-keyed). Horizontal displacement, overturning angle, interface contact stress, and foundation strain were monitored throughout loading. Because the return-type cable transmits a predominantly horizontal force, the anchorage–foundation contact stress exhibits pronounced asymmetry between the toe and heel regions, and this stress asymmetry governs the coupled sliding–overturning instability mode. The shallow flat-base case exhibited a distinct displacement and contact stress jump at high load levels, followed by rapid rotation, indicating slip–tilt coupled instability. Increasing embedment improved confinement and delayed the onset of nonlinear deformation, but the flat-base configuration still showed pronounced toe stress concentration. By contrast, the shear-keyed base mobilized cooperative bearing of the surrounding foundation, producing smoother stress–strain evolution and higher ultimate capacity. Moreover, the shear-keyed base mitigates the stress asymmetry at the anchorage–foundation interface, leading to a more symmetric distribution of contact pressure and improved overall stability. Three-dimensional finite-element simulations reproduced the measured trends in displacement, stress concentration near the toe, and strain development, providing independent verification. The results clarify the dominant instability mechanism of return-type cable gravity anchors and offer design implications for embedment depth and shear-keyed base detailing. Full article

Lightweight structural design is a critical objective in automotive engineering, particularly for suspension components that directly influence unsprung mass and vehicle dynamics. Although topology optimization is widely used to achieve high stiffness-to-weight ratios, conventional approaches are often limited by single-objective formulations or by a lack of geometric interpretability in multi-objective solutions. This study proposes a multi-stage topology optimization framework for the conceptual design of an automotive suspension upright. The methodology decouples stiffness-driven and stress-driven optimization processes and introduces a parametric synthesis stage in which key structural features from both solutions are systematically integrated into a geometrically interpretable design. The framework is evaluated on a Formula SAE front upright under representative braking and cornering load conditions. The resulting hybrid configuration achieves a 29.44% reduction in mass (from 616.9 g to 435.3 g) while maintaining structural performance, with a maximum von Mises stress of 220.0 MPa, a safety factor of 2.28, and a maximum deformation of 0.88 mm. The results demonstrate that the proposed approach enables a balanced integration of stiffness and stress criteria through feature-based design synthesis. Beyond numerical performance, the methodology provides a reproducible and interpretable workflow that bridges topology optimization and practical engineering design. Full article

Graphene possesses exceptional mechanical strength, high electrical conductivity, and a stable lattice structure, making it an ideal material for sensors in advanced manufacturing. However, these sensors face stability challenges due to complex electromagnetic interference (EMI) environments generated by electrical equipment. Therefore, investigating the influence of EMI on sensor performance is of significant importance. In this study, simulations were performed to analyze electrical parameter perturbations of intrinsic graphene films under EMI conditions. The Magnetic Fields, Solid Mechanics, and Electrostatics modules in COMSOL Multiphysics were employed to construct a coupled model of a three-phase power transformer and a graphene-based pressure sensor. The results indicate that EMI can induce baseline drift on the order of ~5% full scale (FS) in the graphene current density, accompanied by degradation in signal-to-noise ratio (SNR) exceeding ~15 dB under typical simulation conditions. Graphene in direct contact with metal electrodes shows enhanced sensitivity to EMI, with more pronounced noise amplification due to interfacial coupling effects. In contrast, cavity-suspended graphene configurations exhibit relatively improved robustness, suggesting that suspended membrane architectures can mitigate EMI by reducing parasitic coupling and enhancing mechanical isolation. Compared with previous studies, this work highlights the role of multiphysics coupling and membrane suspension in influencing EMI-induced perturbations, providing theoretical guidance for the design of graphene-based sensors in power system and industrial Internet of Things (IoT) applications. Full article

This study presents experimental modal analysis of an ultra-lightweight composite structure representative of UAV application and to evaluate the suitability of different testing approaches for reliable identification of its dynamics characteristics. The investigated structure is a winglet made of carbon fiber reinforced polymer (CFRP) with a lightweight foam core. The experiment was based on impact hammer excitation combined with triaxial accelerometer measurements. Modal tests were performed under three different boundary conditions: free–free suspension using elastic cords, free–free approximation using compliant foam support, and fixed conditions reflecting the operational mounting of the winglet. The results confirm that boundary conditions constitute the dominant factor governing the dynamic response. Transition from free–free to fixed support shifted the dominant bending modal frequency from 331.5 Hz (single-sided response) and 329.9 Hz (double-sided response) 421.2 Hz in the fixed configuration, demonstrating a frequency increase of nearly 27%. Reciprocity and double-sided measurements revealed measurable frequency deviations (e.g., 116.3 Hz to 117.6 Hz) attributed to accelerometer mass loading and geometric misalignment. The 1 g triaxial accelerometer mass was shown to be non-negligible relative to the modal mass of the structure, producing observable shifts in higher-order modes. Full article

This paper presents an iterative graph-analytical procedure for determining the roll center height, one of the most critical design parameters influencing vehicle dynamic behavior during cornering. The conventional approaches generally determine roll center locations from suspension kinematics and then evaluate vehicle behavior using multibody or numerical vehicle dynamics models. By contrast, the proposed method is intended for the preliminary design stage and provides a direct correlation between front and rear target roll center heights using tire test data, load transfer and axle-level equilibrium conditions. The main advantage of the method is that it helps define a feasible design space before detailed geometry optimization or MBD validation is performed. The objective is to achieve stable and neutral handling (avoiding intrinsic understeer or oversteer tendencies) during steady-state cornering at a predefined target lateral acceleration. The methodology integrates (i) lateral force equilibrium at the axle level, (ii) a dynamic load transfer model based on axle roll stiffness and roll center heights, and (iii) experimental tire grip characteristics (lateral force–slip angle curves under varying vertical loads), processed through numerical interpolation. The procedure is demonstrated using a vehicle model with specific geometric and mass parameters. The results indicate that the methodology does not yield a single unique solution, but rather a set of correlated roll center heights, allowing the designer to select the most feasible geometric configuration while maintaining neutral handling. As an example, the paper presents a convergent solution for the front and rear roll center heights that satisfy neutrality conditions at a slip angle of approximately 4°. This study provides a fundamental framework for the geometric design of suspension systems and serves as a basis for subsequent numerical and experimental validation. Full article

To accurately evaluate the electric and magnetic field distribution characteristics around transmission lines under different tower structures and operating conditions, this study systematically investigates the spatial electric and magnetic fields of transmission line towers based on Grid Information Model (GIM) file parsing and finite element simulation. First, key information, including tower geometric configuration, conductor suspension point locations, and voltage level, is extracted by parsing the GIM file. A unified transformation method from geographic coordinates to three-dimensional Cartesian coordinates is established, and a three-dimensional electric and magnetic field calculation model is constructed in the ANSYS Maxwell platform, incorporating a catenary conductor model and an equivalent representation of bundled conductors. Furthermore, the accuracy of the proposed calculation method is validated based on field measurement data. Second, under single-circuit operating conditions, the spatial electric and magnetic field distributions of the Goblet-shaped suspension tower and the Drum-type transmission tower are analyzed under different phase sequence arrangements and different conductor-to-ground heights, and the shielding effect of the tower structure on the local electric field is investigated. On this basis, an electric field fitting method based on a proportional polynomial model is proposed, enabling the prediction of electric field distribution under tower-present conditions using simulation results obtained without tower structures. Subsequently, the influence of different phase sequence combinations on the spatial electric field distribution is systematically examined. The fitting method is further extended to double-circuit transmission lines, and its accuracy and effectiveness in rapid electric field assessment are verified. Finally, from an engineering practice perspective, the effects of the presence of jumper conductors and variations in conductor turning angles on the spatial electric field distribution of double-circuit towers are analyzed, and an optimized estimation approach for electric fields under different turning angle conditions is proposed. The results demonstrate that tower structural configuration and conductor arrangement significantly affect the electric field distribution, and the proposed fitting method effectively reduces modeling complexity while maintaining computational accuracy. The findings of this study provide a theoretical basis and technical reference for electric and magnetic environment assessment and engineering design of transmission lines. Full article

Deep soft-rock tunnels are prone to large deformations and structural damage. This study used the Guanyinping Tunnel as a prototype and conducted 1/50-scale progressive loading model tests under three support configurations: rock-bolt-free, equal-length rock bolts, and mixed long–short rock bolts. Rock stress, radial rock displacement (u), and rock bolt axial force (F_N) at the vault, arch shoulders, sidewalls, and wall feet were monitored to reveal reinforcement mechanisms and mechanical response. The results indicated that stress evolution in the bolt-free case exhibited significant spatial heterogeneity. The vault experienced horizontal stress concentration, while the arch shoulder underwent vertical stress concentration. u underwent a three-stage nonlinear progression: elastic linear growth, plastic linear growth, and plastic-accelerated growth. Displacement at the vault was markedly larger than that at other locations. Equal-length rock bolts substantially improved the rock mass stability by delaying stress concentration and fracture propagation. This reinforcement raised the elastic response threshold to 96 kPa and substantially reduced u. F_N at the vault and shoulder followed linear growth, accelerated growth, and then gradual decline, whereas F_N at the sidewalls and wall feet exhibited a steady linear trend. Combined long and short rock bolts produced a multi-level anchoring effect. Short bolts induced a shallow arching action, while long bolts provided deep suspension. This synergy raised the elastic response threshold to a maximum of 120 kPa and moderated the stress reduction process. Deep residual stresses increased to 74.3–88.4% of peak values. The displacement gradient between shallow and deep rock masses was significantly reduced. The coordinated deformation capacity within the anchoring zone was markedly enhanced. F_N distribution exhibited spatial differentiation: short bolts carried the load initially, followed by the activation of long bolts. Both anchoring schemes increased residual stress and mitigated rock mass deformation. The deformation control effect was stronger in shallow rock mass than in deep rock mass. Improvements at the vault and arch shoulders exceeded those at the sidewalls and wall feet. The mixed short–long bolt configuration was superior because it maximized the self-bearing capacity of the deep rock mass. The findings provide experimental data and theoretical guidance for the design and optimization of rock-bolt support in deep soft-rock tunnels. Full article

The safe release of external stores from aircraft is a complex aerodynamic problem governed by strong interactions between the store and the carrier. During separation, the store is subjected to rapidly varying pressure fields, strong aerodynamic interference, and inertial effects that collectively determine the trajectory and stability of the body in the critical milliseconds following release. This study presents a numerical investigation of the separation of an external store from the high-wing configuration aircraft. Both gravitational and impulse-based release mechanisms are examined across multiple suspension stations and a wide range of flight conditions. Computational fluid dynamics (CFD) methods were employed using a density-based, compressible solver with SST k–ω turbulence modeling, combined with a fully coupled six-degree-of-freedom (6DOF) solver and dynamic mesh deformation techniques. The study considers a wide range of Mach numbers from 0.6 to 0.9 and angles-of-attack between −2° and 4°, and three different suspension stations located at the inner wing pylon, outer wing pylon, and fuselage centerline. These conditions strongly influence the aerodynamic environment around the store and therefore affect its initial motion after release and flight path. The impulse ejection forces used in the analysis come from experimental data and are applied through a user-defined function (UDF) at each time step, allowing the simulation to reproduce the ejection event as realistically as possible. Numerical results confirm that the flight paths of external store are highly non-symmetrical, requiring the employment of complex computational models for their successful resolution, and that they gravely depend on the operating conditions, carrier geometry as well as the suspension location. Full article

Background/Objectives: MRI-guided neurovascular interventions could benefit from lower-field systems due to reduced magnetic and radiofrequency hazards. However, safety and practical visibility of commonly used neurointerventional devices at 0.55 T remain insufficiently characterized. We evaluated magnetic field interactions, RF-induced heating, and qualitative device visibility in 11 commercially available and commonly used neurovascular devices on a 0.55 T MRI system. Methods: Eleven devices, including stent retrievers, guidewires, catheters, and one embolization implant, were tested at 0.55 T. Magnetostatic interactions were quantified using the American Society for Testing and Materials (ASTM)-guided deflection methods for translational force (ASTM-F2052) and a two-string suspension apparatus for torque (adapted from Stoianovici et al.). RF-induced heating was measured in an in vitro perfused cerebral vessel phantom using a 15 min high-specific absorption rate spin echo sequence under static and flow conditions. Qualitative device visibility was assessed using a turbo spin echo (TSE) and balanced steady-state free precession (bSSFP) imaging on each device individually. Results: Eight of eleven devices passed the translational force test, while three devices (D, E, and G), containing significant ferromagnetic components, failed with deflection angles > 45°. Eight devices passed torque testing, remaining below the critical threshold in all rotation positions; three devices (D, G, and J) failed by exceeding the 54° criterion, including one guidewire and two devices with braided/coiled metallic structures. Under static conditions, RF-induced heating ranged from negligible to 10.4 °C (maximum in device D) and generally decreased under flow; in the flow configuration, temperature rise remained below 2 °C for 6/11 devices. Qualitative imaging performance differed by sequence, with bSSFP enabling improved delineation of device structure (best for devices A, C, and H), whereas devices D, E, F, and J produced extensive signal voids that precluded reliable visualization in both sequences. Overall, three devices satisfied all safety criteria while remaining clearly visible under MRI. Conclusions: Devices that pass safety thresholds at 0.55 T can serve as candidates for further sequence optimization and preclinical workflow development, enabling the design of low-SAR, device-compatible imaging protocols tailored for neurointerventional workflows. These results provide key safety data supporting the feasibility of MR-guided neurovascular procedures at 0.55 T. Full article