Search Results (2,961)

Rapidly deployable floating bridges face coupled challenges in compact deployment, structural load-bearing, and controllable module maneuvering, which cannot be fully evaluated through a single-stage structural or hydrodynamic assessment. To close this gap, this study proposes a rigid–flexible hybrid floating bridge composed of rigid deck plates, inflatable buoyancy bladders, scissor linkages, and integrated waterjet propulsors. A multi-stage assessment was conducted through inflation and calm-water maneuvering tests, gas–solid coupled finite-element analysis, and hydrodynamic and mooring simulations. The inflation experiment revealed three stages in the inflation process of the rigid–flexible specimen, including filling, transition, and pressurization stages. A remotely controlled scale model completed longitudinal, lateral, rotational, and compound motions, demonstrating the feasibility of module-level maneuvering under manual remote control. The finite-element results showed that increasing the initial internal pressure improved the load-bearing capacity and reduced local plastic deformation of the upper deck, while further improvement became limited above 70 kPa. Under the specified wave–current conditions, the ten-module assembly exhibited maximum mooring tension, horizontal displacement, and rotation of 34.7 kN, 0.276 m, and 5.525°, respectively. These results demonstrate the potential of the proposed configuration for bearing capacity, rapid deployment, and resistance to the investigated current and wave conditions while providing a multi-stage framework for further engineering design. Full article

To address the challenges of structural deformation and limited load-bearing capacity in morphing wings, this paper proposes a novel rigid–flexible composite morphing wing based on a foldable membrane–skeleton structure with a high folding ratio. Inspired by the deployment mechanics of biological wings and the cooperative support principle of multi-bar mechanisms, an optimization model was established to resolve hinge interference in the skeletal design. Through geometric reconstruction of the skeleton, the design achieves compact stowage in the folded state and maximizes wing area in the deployed configuration. Furthermore, an integrated design model for the membrane–skeleton interface was established based on rigid–flexible hybrid connection principles, followed by an analysis of the wing’s static structural characteristics via finite element simulation. A prototype was fabricated to experimentally validate its morphing functionality and out-of-plane load-bearing performance. Results demonstrate that the mechanism attains an effective folding ratio of approximately 7.19. Additionally, the influence of membrane prestress on the overall structural load capacity was systematically investigated. Full article

Data centers are large and rapidly growing electricity consumers, and cooling systems account for a substantial share of their energy demand. A key contribution of this study is a climate-sensitive, hourly techno-economic comparison of three data-center cooling configurations under consistent operating assumptions: a conventional water-cooled centrifugal chiller baseline, a magnetic bearing chiller (MBC) system, and an MBC system integrated with aquifer thermal energy storage (ATES). The comparison is performed for Phoenix, Arizona, and Fairbanks, Alaska, which represent substantially different cooling climates in the U.S. Hourly simulations use identical information technology (IT) load profiles, identical aggregate installed chiller capacity represented by two 4058 kW chiller units, common water-side economizer controls, and site-specific weather and electricity tariffs. Results show that the MBC system reduces annual cooling-system electricity consumption from 1169.4 to 957.4 MWh in Phoenix (18.1%) and from 361.6 to 319.4 MWh in Fairbanks (11.7%). Peak cooling-system electrical demand decreases by 119.4 kW in Phoenix and 71.6 kW in Fairbanks. Relative to the centrifugal baseline, the MBC case gives a 5.8-year simple payback in Phoenix but is not economically attractive in Fairbanks under the assumed tariff. The MBC-only case gives the lowest annual cooling electricity use in both climates. The MBC+ATES case is treated only as a screening-level, discharge-assisted cold-storage scenario rather than a full techno-economic assessment of seasonal ATES, and no site-specific hydrogeological feasibility assessment is performed. Under the assumed O&M cost structure, MBC+ATES gives a higher discounted value of savings than MBC-only, but this economic result is not caused by additional cooling-electricity savings relative to MBC-only. The MBC+ATES case also has a longer payback period because of its higher capital cost. These results show that the value of advanced cooling configurations depends on climate, free-cooling availability, electricity pricing, storage assumptions, and economic assumptions within the modeling framework considered in this study. Full article

Hinge joints are critical structural components that connect precast girders and enhance the load-bearing capacity and serviceability of multi-girder bridges. Damage to hinge joints can significantly reduce the structural integrity of a bridge and may even lead to bridge collapse. This study numerically investigated the effects of hinge-joint damage on the mechanical performance and inter-girder connections of a hollow-slab girder bridge using a surface-based cohesive behavior model. Hinge-joint damage was simulated in the finite element software ABAQUS (version 2022) using bond-performance degradation at the slab–hinge joint interfaces. The effects of damage location and severity on the stress distribution within the hinge joints were evaluated. The results reveal that damage in two hinge joints produces stresses 15% higher than those caused by damage in a single hinge joint. This indicates a weak superposition effect among multiple damaged joints. Additionally, stress fluctuations at key points Nos. 1 and 2 are significantly greater than those at key points Nos. 3 and 4. These findings provide valuable guidance for improving the durability and crack resistance of hinge joints and designing and maintaining multi-girder bridges. Full article

Static wake steering can increase wind-farm power production, but its application to floating offshore wind farms requires assessment of the coupled wake, platform, structural, and station-keeping response. This study evaluates whether power-maximizing static yaw setpoints identified using the steady, control-oriented FLORIS model retain their benefit when transferred without re-optimization to a coupled FAST.Farm floating wind-farm model. The reference farm comprises four IEA Wind 15 MW turbines mounted on VolturnUS-S semi-submersible platforms. Greedy and static wake-steering operations are compared at three below-rated wind speeds, three sea states, and five matched turbulent-inflow realizations, resulting in 90 farm-level FAST.Farm simulations. Wake behavior is characterized through wake-center deflection, meandering, and velocity-deficit profiles, while turbine and mooring fatigue responses are evaluated using paired damage-equivalent-load statistics. Static wake steering increases mean farm power under all nine investigated wind–wave conditions. The gains are approximately 5.1–$5.2\%$ at $7\mathrm{m}{\mathrm{s}}^{-1}$, $5.0$–$5.1\%$ at $8\mathrm{m}{\mathrm{s}}^{-1}$, and $4.0$–$4.2\%$ at $9\mathrm{m}{\mathrm{s}}^{-1}$, with all paired $95\%$ confidence intervals remaining above zero. The gain results from a power redistribution in which the intentionally yawed upstream turbine incurs a local loss that is exceeded by the combined recovery of the downstream turbines. The fatigue response is strongly component- and turbine-dependent. The paired farm-mean blade-root DEL decreases by $0.82$–$2.24\%$, whereas the tower-base DEL increases by $0.76$–$2.78\%$, and the FairTen1 response generally increases by $0.88$–$2.92\%$. The farm-mean yaw-bearing response is mixed, ranging from a $1.15\%$ reduction to a $4.32\%$ increase. Turbine-level analysis reveals larger localized penalties, reaching approximately $10.4\%$ for the yaw-bearing DEL and $12.8\%$ for FairTen1. Spectral analysis associates the yaw-bearing response with yaw-induced aerodynamic and structural excitation, while the tower-base response is strongly influenced by low-frequency wave–platform dynamics. A complementary FLORIS sensitivity analysis demonstrates that the optimized aerodynamic benefit depends strongly on wind direction, spacing, wind speed, and turbulence intensity. For a Tampen-derived 11-turbine layout, resource weighting over the modeled 4–$13\mathrm{m}{\mathrm{s}}^{-1}$ interval produces an annual energy-contribution increase of $3.653\mathrm{GWh}{\mathrm{year}}^{-1}$, or $0.921\%$. These results provide numerical evidence that static wake steering can retain a positive power benefit in a coupled floating wind-farm environment, but controller assessment must include turbine- and component-specific dynamic loads rather than farm power alone. Full article

Phenolic aerogels, owing to their low density, high char yield, large specific surface area, and well-defined three-dimensional topological networks, hold considerable promise for applications in extreme thermal protection and multifunctional material systems. The sol–gel process, a cornerstone methodology for constructing the three-dimensional nanoporous architecture of these materials, critically governs the resulting microstructural topology and macroscopic performance through its reaction kinetics, phase-separation behavior, and drying dynamics. This review systematically surveys recent advances in the sol–gel synthesis of phenolic aerogels, focusing on the polycondensation mechanisms operative under acidic and basic catalytic conditions, nucleation-and-growth kinetics, and strategies for tailoring multiscale pore structures. It further provides a comparative analysis of interfacial regulation mechanisms for capillary-stress elimination across supercritical drying, freeze-drying, and ambient-pressure drying routes. We also dissect the structure–property relationships underpinning Knudsen-effect-mediated gaseous thermal insulation, multi-scale hybrid network toughening, and inorganic phase-transition-induced in situ ceramization for thermal protection, demonstrating the synergistic optimization of thermal insulation, structural load-bearing, and ablation resistance. Finally, we summarise current applications in extreme thermal protection, environmental adsorption, electromagnetic interference shielding, and electrochemical energy storage and highlight future directions towards green, scalable manufacturing and intelligent materials design. Full article

Ring-stiffened cylindrical shells are widely used as load-bearing components in submarine pressure-hull sections. Existing underwater explosion studies have mainly emphasized incident-face denting or global failure, leaving unresolved how circumferential shock-wave diffraction and internal structural load transfer produce different response sequences and plastic-strain accumulation at the incident, side, and rear faces. A mechanism-oriented underwater explosion model test was conducted using a 44 g TNT charge at a stand-off distance of 0.50 m, and a fluid–structure interaction model was established in MSC.Dytran using the general coupling method. The model incorporated the Cowper–Symonds strain-rate effect of 16MnR steel and was validated against the Cole empirical peak pressure and measured incident-face residual deformations. The calculated free-field peak pressure was 35.50 MPa, with an error of 0.65%, while the mean relative error of the six residual-deformation measurements was 13.50%. The shell plating between adjacent ring stiffeners exhibited higher velocity and acceleration peaks than the stiffeners, indicating the local constraint imposed by the ring stiffeners. The side-face nodes showed symmetric transverse expansion, and the corresponding elements exhibited no discernible equivalent plastic strain. The rear-face center displayed a delayed axial response, and its representative element reached a final equivalent plastic strain of approximately $1.32\times {10}^{-3}$, compared with $0.40\times {10}^{-3}$ for the incident-face element. These results identify distinct circumferential response modes and show that macroscopic motion amplitude is not simply correlated with local plastic deformation. Full article

Battery packs for new energy vehicles have evolved from simple load-bearing and protective assemblies into multifunctional safety structures integrating structural support, crash protection, thermal-runaway mitigation, flame retardancy, electrical insulation, electromagnetic interference shielding, waterproof sealing, and long-term reliability. Fiber-reinforced polymer composites are promising for upper covers, underbody shields, trays, cross beams, side frames, and local protective structures because of their low density, corrosion resistance, design flexibility, and functional-integration potential. However, composite-part performance is strongly governed by forming. Resin flow, impregnation, curing or cooling shrinkage, fiber orientation, filler dispersion, and interfacial bonding may induce voids, dry spots, resin-rich regions, delamination, warpage, and fiber waviness, thereby affecting load bearing, sealing, thermal protection, and durability. This review focuses on composite-forming technologies for new energy-vehicle battery packs. It summarizes component-level service requirements and material systems and compares representative forming routes, including sheet molding compound (SMC), prepreg compression molding/wet compression molding (PCM/WCM), resin transfer molding/high-pressure resin transfer molding (RTM/HP-RTM), vacuum-assisted resin transfer molding (VARTM), long-fiber thermoplastic direct processing (LFT-D), glass-mat thermoplastic (GMT), thermoplastic sheet forming, pultrusion, and multi-material joining. These routes are evaluated from six dimensions: material form, forming cycle, typical defects, representative mechanical performance, applicable components, and engineering maturity. The review further discusses defect mechanisms, performance effects, detection and control methods, and the roles of in-line monitoring, non-destructive testing, process simulation, machine learning, and digital twins in closed-loop quality manufacturing. Finally, engineering challenges are examined in multi-material joining, thermal-safety integration, low-carbon recycling, and standard certification. Composite-material battery-pack structures should therefore be developed as coordinated design and closed-loop manufacturing systems linking materials, processes, defects, performance, and validation. Full article

Metal-plate-connected (MPC) joints govern the stiffness and load-bearing performance of many prefabricated timber roof trusses, yet their response to repeated moisture changes remains critical for serviceability and durability. This study evaluated five continuous C24 Norway spruce reference specimens and fifteen specimens joined with GNA20-MIT nail plates using sequential four-point-bending stiffness measurements and wetting–drying conditioning. Test I was used as the initial stiffness stage, whereas Tests II and III followed successive 24 h water-immersion and 6-day natural-drying intervals; the specimens were subsequently tested to failure. The mean apparent modulus of elasticity of the MPC specimens decreased from 1.39 to 1.22 GPa (approximately 12%), but a Friedman repeated-measures test did not show a statistically significant stage effect (χ²(2) = 4.13, p = 0.127). Because the same specimens were repeatedly loaded, and no unexposed MPC control group was included, this change cannot be attributed exclusively to moisture cycling. In the primary analysis retaining all 15 MPC specimens, the mean apparent bending strength of the connected elements was 16.92 MPa, compared with 34.14 MPa for the structurally different continuous reference specimens; excluding M7 yielded 17.87 MPa only as a sensitivity analysis. Failure of the connected specimens was progressive and dominated by plate slip and partial spike withdrawal, whereas solid specimens failed more abruptly in bending. The results therefore support attention to connection flexibility and serviceability under variable environmental and loading histories, while further controlled testing is required to isolate the specific contribution of moisture cycling. Full article

This study investigates fire behavior and personnel evacuation safety in a nuclear chemical workshop based on the Fire Dynamics Simulator (FDS) and real fire experiment. The typical fire scenario caused by cable faults at middle distribution box locations was analyzed to evaluate the effects of ignition position on fire growth and smoke propagation. The FDS results show that the upper-layer temperature reaching approximately 180 °C at 173 s, while visibility at 2 m height decreases to 10 m at 176 s and CO₂ concentration rises to 1%. The CO concentration at 2 m reaches 500 ppm at around 290 s. The calculated Available Safe Egress Time (ASET) of 145 s exceeds the Required Safe Egress Time (RSET) of 117 s, indicating acceptable evacuation safety under this scenario. A full-scale real fire experiment was further conducted under a 5 MW fire. Temperature measurements showed that the thermocouple tree nearest the fire source reached a maximum temperature of approximately 620 °C, posing a severe threat to unprotected steel roof structures. The temperatures below 2 m remained relatively lower, decreasing from about 250 °C to 150 °C. These results demonstrate that the concentrated fire scenario primarily endangers roof load-bearing structures, whereas the thermal conditions in the evacuation zone are comparatively less severe. Full article

To address the insufficient load-bearing capacity and overall stiffness of timber truss roofs in brick–timber and earth–timber structures in rural areas, as well as the requirements for preserving traditional architectural characteristics, a steel–timber composite roof system was proposed. The system was developed through rational integration of timber and steel components to enhance the overall mechanical performance of the structure. At the joint level, flexural performance tests were conducted on cramp-iron joint, gusset–plate joint, and steel–timber joint. The moment–rotation relationships, failure modes, and ductility characteristics of the three joint types were systematically investigated. Based on the experimental results, a trilinear moment–rotation model was established. Furthermore, a finite element model of the roof structure was established using SAP2000 (26.2.0), and the stress distribution and load–displacement responses under horizontal static loading were analyzed through numerical simulation. The influence of different joint configurations on the mechanical performance of the roof structure was evaluated from an overall structural perspective. The results demonstrated that the peak bending moment of the steel–timber joint was increased by approximately 163.50% and 3.74% compared with those of the cramp-iron joint and gusset–plate joint, respectively. The ductility coefficient was enhanced by approximately 9.33% and 62.91%, respectively. In the finite element model of the roof structure, the peak load of the roof system with the steel–timber joint was increased by approximately 114.96% and 9.54%, while the corresponding displacement capacity was improved by approximately 76.62% and 43.41%, compared with the other two roof systems, respectively. Future studies will focus on further evaluating the seismic performance of steel–timber composite roof systems through cyclic loading experiments, dynamic response analysis, and full-scale structural validation, thereby providing a more comprehensive understanding of their long-term applicability in earthquake-prone rural buildings. Full article

This paper investigates the degradation law and calculation method for the load-carrying capacity of steel–concrete composite girders under fire exposure based on numerical analysis and mathematical statistics. A finite element model of simply supported box-section steel–concrete composite girders is established using ABAQUS, which is validated against existing scaled test data in terms of temperature field distribution, load-carrying capacity, and mid-span displacement. On this basis, the parametric effects of concrete slab thickness, steel web height, steel plate thickness, and concrete strength on the load-carrying capacity of the girders are systematically analyzed. The results indicate that concrete slab thickness, steel web height, and steel plate thickness exert significant influences on the structural bearing capacity, whereas concrete strength has a negligible effect. Specifically, the load-carrying capacity under fire exposure is substantially improved with the increase in concrete slab thickness, steel web height, and steel plate thickness. Furthermore, a simplified calculation formula for the capacity of box-section steel–concrete composite girders under fire exposure is developed via multiple linear regression analysis, incorporating the three dominant influencing factors of concrete slab thickness, steel web height and steel plate thickness. The proposed formula exhibits satisfactory calculation accuracy and can provide a reliable reference for the fire resistance design and repair decision-making of steel–concrete composite girders. Full article

Vernacular heritage conservation often separates material fabric, environmental adaptation, and social meaning. This study addresses that separation for one settlement. Socio-environmental heritage is defined here as heritage whose significance resides in the documented interdependence of environmental conditions, material practice, social organisation, and customary governance, rather than in fabric or imagery alone. The single purpose of the article is to develop and demonstrate an evidence-based method for interpreting and conserving Thee Ain Heritage Village in Al-Baha, Saudi Arabia, as such a system. A qualitative architectural case-study design combines a structured literature search, regional comparison, the author’s 2014 field observations and photographs, and published digital-heritage, energy-retrofit, and conservation studies; no human-participant data are analysed. Evidence is organised through three analytical layers—climatic material, socio-spatial, and customary governance—and each evidence–interpretation proposition is classified as directly observed, supported architectural inference, or hypothesis requiring measurement; conservation translation is treated as the output of this sequence rather than as a parallel analytical layer. Coded claim units are documented individually so that every interpretation and implication can be traced to its source, strength, and limitation. The analysis links rocky siting, stone and timber assemblies, thick load-bearing madameek walls, limited openings, vertical domestic hierarchy, controlled thresholds, and the agricultural setting to conservation priorities at landscape, construction, spatial, and adaptation scales. These priorities include compatible repair, retention of wall depth and opening logic, protection of privacy gradients and threshold sequences, and service integration without reducing the village to stone-clad imagery. Unlike previous work centred on digital documentation, energy modelling, or policy-level preservation, the contribution is an evidence-structured method linking architectural observation to bounded interpretation, conservation decisions, and explicit future testing requirements. Full article

Accurate specification of spatial heat sources is required for liquid fuel molten salt reactors, given the redistribution of deposited energy among fuel salt, graphite, and metallic structures by gamma ray transport. In this study, a refined power deposition framework based on Monte Carlo particle transport was formulated for a 150 MW thorium molten salt reactor to quantify particle, material, and spatial contributions to the core heat source. The calculation was performed under a static fuel salt approximation, in which flow-induced transport of delayed particle precursors in the circulating fuel salt was not explicitly considered. Particular attention was given to gamma ray generation, transport, and deposition, as well as to the resulting refined power density distribution. The results show that gamma rays contribute 7.64 MW to graphite heating, approximately 3.11 times the neutron contribution. In the alloy sleeve, capture gamma rays account for 63.44% of the deposited power, producing an average power density of 9.34 MW/m³, nearly 18 times that in graphite. This behavior is primarily associated with the strong neutron capture capability of the tungsten bearing alloy and the relatively short gamma ray mean free path in this material. The refined power density distribution further indicates that fuel salt channel power density decreases from about 100.0 MW/m³ near the core center to 57.7 MW/m³ near control rod assemblies, while local graphite power density varies by more than 40%. These findings indicate the need for spatially resolved and material specific heat source descriptions in thermal hydraulic coupling and structural heat load assessment, rather than material averaged treatments or fixed fuel to graphite scaling. Full article

A variety of measurement systems are available for monitoring existing concrete bridges with deficiencies in shear capacity. In addition to established systems, fiber optic sensors (FOS) offer significant potential for structural health monitoring. However, FOSs are often installed in the tension zone, where crack formation may occur even under service loads, increasing the risk of sensor failure and potentially resulting in a loss of measurement capability. A promising approach to significantly reduce this risk is the installation of FOSs in the compression zone. However, it remains unclear whether measurements obtained from FOSs in the compression zone can be used to assess the load-bearing and deformation behavior of reinforced concrete beams and how they relate to measurements obtained in the tension zone. To address this question, shear tests were carried out on reinforced concrete beams with shear reinforcement ratios commonly used in practice. The experimental results demonstrate close agreement between measurements obtained from FOSs installed in the compression and tension zones under service loads. Furthermore, the findings and the characteristic strain profiles associated with shear and flexural failure provide a basis for assessing existing structures monitored using FOSs. Full article