Search Results (402)

In modern multistory buildings, integrating beam web openings adjacent to beam–column connections (BCCs) is frequently required to accommodate utility ducts and piping. While this optimizes clear story height, it drastically alters the stress distribution within the BCCs under seismic loading. Consequently, this study evaluates the seismic performance of twenty-one exterior BCCs, with particular emphasis on the coupled effects of opening configuration (size and location) and concrete type: normal strength concrete (NSC, f_c′ = 25 MPa), high-strength concrete (HSC, f_c′ = 80 MPa), and ultra-high-strength concrete (UHPC, f_c′ = 120 MPa). For BCC specimens without openings, upgrading from NSC to HSC and UHPC increased the failure load (P_f) by about 66.67% and 111.11%, and the ultimate capacity (P_u) by 61.54% and 100.0%, respectively. Conversely, web openings reduced the (P_u) of HSC specimens by 14–34%, and UHPC specimens by 12–31%, respectively, when compared to the reference specimens without openings. Furthermore, the presence of web openings compromised cumulative energy dissipation capacity by 16–36% for (NSC), 13–31% for (HSC), and 12–28% for (UHPC), compared with the corresponding reference specimens without openings. Although HSC and UHPC provided superior absolute energy performance, they did not eliminate the structural deficiencies associated with openings positioned adjacent to the joint core. Consequently, a critical threshold value of S/D ≥ 0.5 (where S represents the distance from the column face to the edge of the opening, and D denotes the beam depth), is recommended for HSC and UHPC. In contrast, conventional NSC strictly requires a more conservative limit of S/D ≥ 1.0 to prevent severe cyclic shear degradation near the high-stress region. Full article

Background: Precise intraoperative localisation of small colorectal tumours during laparoscopic surgery remains challenging due to absent tactile feedback and subserosal tumour location. Current standard methods, particularly India ink tattooing, demonstrate 15–30% failure rates for lesions less than 10 mm, leading to prolonged operative times, incomplete resections, and re-operations. Multiple emerging technologies promise improved localisation, yet comparative evidence remains fragmented. Objective: To map and characterise the current landscape of intraoperative marking and identification technologies for small colorectal tumour localisation during laparoscopic surgery, with emphasis on radiofrequency-based methods and alternative approaches, and to identify evidence gaps guiding future research. Methods: Following PRISMA-ScR guidelines, we systematically searched PubMed, Web of Science, and Scopus databases from January 2000 through December 2025 for studies evaluating tumour localisation technologies in colorectal cancer surgery, including primary tumour localisation during laparoscopic colectomy and localisation of colorectal liver metastases during hepatic surgery, or transferable anatomical applications with documented translational potential to colorectal surgery. Two independent reviewers screened all records, with discrepancies resolved through discussion and a third senior reviewer consulted for unresolved disagreements; data were extracted on technical performance, safety, feasibility, cost-effectiveness, usability, innovation potential, and evidence quality. Results: We included 89 studies comprising 18 colorectal-specific articles and 71 transferable/GI-adjacent studies. Detection success rates ranged from 71% to 100% across modalities. Near-infrared fluorescence with indocyanine green demonstrated the strongest clinical evidence with 75–100% detection across eight colorectal studies encompassing 2134 procedures and seamless workflow integration. Radiofrequency identification systems achieved 91.9–99% detection in feasibility studies with promising tissue penetration of 15–35 mm but limited colorectal validation. Electromagnetic navigation excelled in rigid organs with 85–98% success but showed degraded performance in mobile bowel at 71–75%. Critical evidence gaps included absent head-to-head comparative trials, non-standardised outcome metrics limiting cross-study comparability, and limited long-term safety data with only 14 studies providing follow-up exceeding six months. Conclusions: ICG fluorescence represents the most clinically mature technology identified, representing a priority candidate for colorectal-specific validation in challenging localisation scenarios. RFID systems demonstrate promising characteristics justifying prioritised research investment through adequately powered comparative trials. Future research must emphasise consortium-based comparative effectiveness studies, standardised outcome metrics, and integration with robotic and AI-assisted surgical platforms to accelerate clinical translation. Full article

With the rapid development of the hydrogen economy, Type IV composite pressure vessels have emerged as the core components of on-board hydrogen storage systems. However, accurate fatigue life prediction remains a critical bottleneck limiting their design optimization and safe operation. Existing methods often exhibit prediction errors exceeding ±50% due to the inherent scatter, anisotropy, and complex service environments of composites. This study proposes an improved simulation method for fatigue life prediction of Type IV cylinders. Systematic tension–tension fatigue tests were conducted on carbon fiber-reinforced polymer (CFRP) laminates at four ply angles (0°, ±15°, ±30°, ±45°) and PA6 liner at three temperatures (−30 °C, 25 °C, 82 °C) to establish comprehensive S-N curve databases. The results reveal that ply angle is the predominant factor governing CFRP fatigue performance, while temperature significantly influences PA6 behavior, and failure mode transitions from fiber fracture to matrix-dominated damage as ply angle increases. A fatigue analysis model was developed in nCode, incorporating the ply fatigue Algorithm to characterize the anisotropic fatigue behavior of CFRP overwraps. Full-scale validation on Type IV cylinders under cyclic pressure (2–87.5 MPa) confirmed the method’s effectiveness, achieving prediction errors of 11.5% and 35.3% for the two failed specimens, with failure locations well predicted. This study provides a rapid and reliable engineering calculation method and data support for the anti-fatigue design, safety assessment, and life management of Type IV cylinders. Full article

This paper presents an innovative asset management system developed by ISOIL to predict pipe failures and reduce non-revenue water losses in distribution networks. The system combines advanced risk assessment algorithms with mobile data collection tools to identify critical pipeline sections and optimize replacement strategies. Applied to a medium-sized utility in Northern Italy, the approach successfully identified 2.36% of the network (~38 km) with the highest vulnerability levels. The predictive model demonstrated 68% accuracy in identifying locations where new leaks subsequently occurred, validating its effectiveness for proactive maintenance planning and leak detection optimization. Full article

Aerospace canopies require both high impact resistance and optical transparency for pilot safety and aerodynamic shielding. While polycarbonate (PC) and poly(methyl methacrylate) (PMMA) are widely utilized, their vulnerability to strain-rate-dependent failure during high-velocity bird strikes necessitates advanced reinforcement strategies. This study presents a multiscale computational framework for nanoparticle-reinforced PC nanocomposites. To circumvent the prohibitive computational costs of atomistic simulations, a novel Strain-Rate Dependent Micromechanics (SRDM) framework is proposed for silica-, alumina-, and zirconia-reinforced PC systems, integrating the Goldberg constitutive model with Halpin–Tsai micromechanics to generate rate-dependent stress–strain responses and calibrate Johnson–Cook (J-C) parameters for impact-scale simulations. Unlike conventional approaches relying on atomistic simulations or empirical fitting, the proposed framework directly links micromechanical nanocomposite modeling with finite element bird-strike simulations. Bird-strike analyses were performed in LS-DYNA on a generic fighter canopy model. The framework further incorporates literature-based optical transparency criteria considering nanoparticle size and refractive-index compatibility. Among the investigated nanofillers, silica-reinforced PC provided the most favorable response. At the most critical impact location, the maximum canopy deformation decreased from 118.6 mm for neat PC to 61.9 mm, corresponding to an approximately 48% reduction. Although the reinforced canopy exhibited a reduction in peak internal energy absorption from approximately 10 kJ to 5 kJ due to its increased stiffness and reduced plastic deformation, it provided improved deformation resistance and structural stability under impact loading. Overall, this work provides a computationally efficient framework for designing bird-strike-resistant transparent nanocomposite canopy structures using nanofiller systems previously reported in the literature to preserve optical transparency. Full article

Medium-voltage distribution networks are an important element of the global power system, being responsible for the distribution of electrical energy from transformer stations to local points of delivery and to transformer stations of lower voltage levels. The reliability of the operation of these networks has a direct impact on the continuity of energy supply and the level of unmet energy demand in the power system. The article presents a reliability analysis of a selected segment of a medium-voltage distribution network located in northern Poland. In this study, a probabilistic model of the operation process based on an eight-state graph describing successive levels of technical degradation of the analyzed network was applied. Transitions between the states of the model were described by failure intensities and restoration intensities of the system elements. On the basis of the Kolmogorov–Chapman state equations, the probabilities of the system being in particular operational states were determined. The results obtained were then used to assess the energy-related consequences of failures by linking state probabilities with the share of unmet energy demand. The analysis conducted enabled the identification of the most critical elements of the analyzed network structure and the determination of their impact on the energy supply capability of the distribution network. The obtained results may constitute a basis for planning operational activities, maintenance strategies, and modernization processes of medium-voltage distribution networks. Full article

This study addresses two critical issues in power material warehouse management: insufficient positioning accuracy leading to inefficient inventory auditing and uncontrolled material movement, and procurement-demand imbalances caused by subjective forecasting methods. We present an integrated warehouse management system that synergizes Ultra-Wideband (UWB) centimeter-level real-time positioning with data-driven demand forecasting. The UWB subsystem, built on STM32F1 microcontrollers (STMicroelectronics, Geneva, Switzerland) and DW1000 RF modules (Decawave Ltd., Dublin, Ireland), achieves high-precision location tracking by employing the Double-Sided Two-Way Ranging (DS-TWR) method combined with trilateration and triangular centroid algorithms. The data-driven procurement subsystem utilizes a vast historical dataset (4.86 million records from 36,988 grid projects, 2020–2024) to train demand prediction models. A comparative evaluation of six algorithms identified the Random Forest (RF) model as optimal, demonstrating superior performance with 89.2% accuracy, a Mean Absolute Error (MAE) of 5.48, and a Mean Absolute Percentage Error (MAPE) of 4.89%. The RF model effectively incorporates key factors like failure rates and seasonal cycles. Experimental validation confirmed the UWB subsystem’s robustness, with an average positioning error of 12.05 cm. The integrated system enables precise material tracking, 3D trajectory reconstruction, and generates data-informed procurement signals—including replenishment warnings, optimized order quantities, and adaptive resupply cycles. This approach significantly reduces surplus inventory while maintaining high material availability, offering a scientific, data-driven solution for enhancing efficiency in power material management. Full article

This paper examines the effectiveness of deposit insurance in reducing bank run risk using an agent-based model with heterogeneous depositor behavior, including random withdrawals, risk-based responses, and peer-driven contagion. The results reveal a nonlinear stability pattern with a narrow transition region separating solvency from collapse. Within this region, deposit insurance mainly improves stability by shifting the critical threshold and extending time-to-failure. Across all scenarios, behavioral and structural factors, including wealth inequality, risk aversion, depositor awareness, and contagion, systematically affect the location and sharpness of this transition without removing it. Fragility rises sharply beyond moderate inequality (Gini ≈ 0.5), while depositor awareness and peer effects act as coordination mechanisms that accelerate collapse. Overall, deposit insurance is a powerful but limited stabilization tool: it strengthens resilience but does not alter the underlying dynamics of systemic risk. These findings suggest that effective policy must also address the behavioral and informational drivers of bank runs. Full article

This paper presents an investigation into the structural behavior of a suspension bridge exposed to an oil-tanker-truck fire. A coupled CFD-FEM analysis model is established to incorporate realistic oil-tanker fire scenarios and multiscale thermo-mechanical coupling, allowing the local thermal responses of critical components and global structural behavior of the suspension bridge to be captured within a unified framework. This model is validated to investigate thermal and structural responses on suspension bridges under different fire exposure lengths and locations influenced by transverse wind. Herein, this response embraces temperature rise, deflection progression, stress evolution in the main cable, force redistribution of hangers, and global failure evolution. Thereafter, failure assessment methods for main cables and hangers in suspension bridges exposed to oil-tanker-truck fires are proposed. The predominant results indicate that crosswind causes the flame to tilt toward and even fully envelop the main cable. Rapid temperature rise along the circumference of the main cable accelerates the degradation of cable load-carrying capacity, eventually leading to main cable rupture and global collapse of the suspension bridge. The proposed main-cable failure assessment method, based on fire exposure duration and surface temperature, can rapidly estimate the fire-resistance limit of main cables. Ruptured hangers lead to upward jumping of deflection in the main cable and a downward deflecting of the main girder. Force redistribution to adjacent hangers may trigger successive ruptures, and the force-based assessment method effectively evaluates the progressive collapse of a suspension bridge subjected to an oil-tanker-truck fire. Full article

Background: Hip implant fractures are rare, yet difficult to correct once they occur. For cemented implants, fracture is often associated with increased stresses at the implant stem when proximal regions of the implant have debonded. While deterministic analyses offer predictive power by using averages for model inputs, averages fail to capture the variability inherent in device manufacturing and musculoskeletal biology. This study developed a probabilistic finite element model of a debonded hip implant to better account for some of these variabilities to predict the most likely failure mode. The hypothesis was that fatigue would be more likely to occur than overloading. Methods and Materials: Monte Carlo sampling generated 1000 simulations varying the material elastic modulus (implant, cement, and bone) and loading magnitude at stance phase of the gait. The resultant distributions of maximum von Mises stress at the stem were compared to distributions for failure properties in the literature. Results: The analysis found the likelihood of the implant failing due to overloading was remote. In contrast, fatigue failure had a 99.4% chance of occurring. Fracture mechanics predicted that the debonded implant would reach critical flaw length between 1.8 and 26.4 months, with a mean of 7.2 months. Conclusions: The results show good agreement with the findings of the case study the model was based on, particularly in predicting the location of failure and fatigue life. The results of this study provide a framework for developing future decision-making tools that ultimately may assist clinicians in deciding when interventions are necessary to minimize the risk of implant or periprosthetic fracture. Full article

Grouted sleeve connectors are critical components in precast concrete structural joints. This study investigates the effects of grouting defect location, quantity, and grout strength on the bond–slip constitutive relationship at the steel–grout interface in fully grouted sleeves. Fifteen centrally loaded pull-out specimens were designed using the controlled variable method and tested under monotonic tension. Failure modes, ultimate load, bond stress, and slip characteristics were analyzed. Numerical modeling was performed using ABAQUS, and a mathematical bond–slip constitutive model was developed. The experimental results show that all specimens with a single defect failed by tensile fracture of the reinforcing bar, whereas those with multiple defects exhibited bar pull-out failure, which most significantly degraded connection performance. Grout strength positively correlated with interfacial bond performance. Deviation of the water-to-binder ratio from the standard value reduced grout strength, leading to decreases in bond strength, ultimate load, and slip. The apparent increase in bond stress under multiple defects was attributed to the reduced effective anchorage area rather than enhanced interfacial bonding, resulting in the lowest actual ultimate load among all scenarios. The established bond–slip constitutive model achieved a coefficient of determination R² ≥ 0.96, indicating excellent fit. The finite element simulations agreed well with test data and accurately reproduced the bond–slip response under various defect conditions. The proposed constitutive model and finite element modeling approach provide a theoretical and quantitative basis for performance assessment of grouted sleeve connectors in engineering practice. Full article

The seismic design of spatial joints in long-span concrete-filled steel tube (CFST) arch bridges under complex stresses remains a critical challenge in high-intensity seismic zones. This study investigates the seismic performance and failure mechanisms of CFST spatial KT-type joints, using the Pingnan No. 3 Bridge as a case study. Based on similarity theory, four scaled test specimens were designed. The core variable was the axial compression ratio of the main pipe, while the load on the K-branch served as the parametric variable. Quasi-static tests were conducted under constant static loading on the main pipe and K-branches, coupled with low-cycle cyclic loading on the T-branch. Furthermore, nonlinear finite element analysis (FEA) was performed using Abaqus for cross-validation. The results indicate that the primary failure mode of this joint configuration is the shear-punching failure of the main pipe wall at the T-branch intersection. The load–displacement hysteresis curves exhibit a robust “bow-shaped” profile, indicating substantial plastic energy dissipation capacity. Comparative analysis confirms that hollow steel pipe T-branches offer superior ductility in long-span arch bridges compared to concrete-filled alternatives. By extracting shear stress distribution characteristics from the FEA model to precisely locate the neutral axis, this study proposes a theoretical correction to the ultimate load-carrying capacity calculation model. The derived theoretical values demonstrate good agreement with the experimental results. The relative errors between the calculated and experimental bearing capacities of KT783a, KT783, KT700, and KT607 were 1.99%, 0.23%, 2.26%, and 2.45%, respectively, referring to the T-branch out-of-plane bearing capacity predicted by the proposed formula. The proposed theoretical model provides a reliable quantitative basis for the seismic design and local strengthening of similar spatial joints in long-span CFST arch bridges. Full article

This paper presents a numerical assessment of bending-fatigue durability in the tooth root region of cylindrical involute gears. Multiple gear pairs were modelled with different numbers of teeth and varying gear rim thicknesses. The generated geometry was implemented in the ANSYS 2025 R2 software suite, where the maximum normal stresses at critical locations in the tooth root region were determined through numerical simulation. A deformation-based method derived from Socie’s models was applied to estimate the duration of the phase leading up to fatigue crack formation in terms of load cycle accumulation. The gear geometry, together with the generated finite element mesh, was transferred to the FRANC2D/L version 4 software suite, where fatigue crack propagation was numerically simulated. Numerical analysis provided effective stress intensity factors, which then enabled an estimation of the number of load cycles required for an initiated crack to grow to the critical length associated with tooth failure. The total fatigue life in the tooth root region was evaluated as the sum of load cycles in the crack initiation phase and the crack propagation phase up to the critical crack length. The results show that all analysed factors exhibit very high resistance to fatigue fractures in the tooth root region. Furthermore, for gears with a rim thickness ratio greater than 0.7, the fatigue crack propagates through the tooth and reaches the fracture toughness limit of the material (K_Ic), whereas for lower rim thickness ratios, crack propagation occurs through the gear rim itself. Full article

The low-cycle fatigue failure of drive shafts under complex service conditions constitutes a critical issue that undermines the structural integrity and service safety of the transmission system in special vehicles. To improve the prediction accuracy of the low-cycle fatigue life of drive shafts, a low-cycle fatigue life prediction method for the drive shaft that accounts for load effects and strength degradation is proposed. A fatigue life prediction model that accounts for the mean stress effect and fatigue strength degradation is proposed by introducing dynamically degrading fatigue strength into the mean stress-refined SWT (Smith–Watson–Topper) model. A fatigue cumulative damage model that considers load interactions and fatigue strength degradation is also proposed, in which the load ratio is introduced to quantitatively describe the extent of the influence of load interactions on the damage process. Furthermore, the dynamically degrading fatigue strength is incorporated into the M-H (Manson–Halford) model. Finally, the stress–strain responses at the critical locations of the drive shaft are analyzed using the finite element model, and the fatigue life of the drive shaft under the load spectrum is calculated using the improved fatigue life prediction model and the improved fatigue cumulative damage model. The results indicate that the improved life prediction method, which considers load effects and strength degradation, can effectively enhance the accuracy of fatigue life prediction for the drive shaft. Full article

To address the issue of coordination failure in multi-stage surge protective devices (SPDs) under lightning surges in communication power systems, this study employs traveling wave propagation theory and electromagnetic transient simulations using the PSCAD/EMTDC platform. It systematically evaluates how lightning strike location, interstage cable length, and load type affect energy coordination and overvoltage response in a two-stage SPD configuration. By combining time-domain and frequency-domain analysis, the coupling mechanism of SPD conduction timing is revealed. There exists a critical length for the interstage cable to ensure coordinated operation of the SPDs. This critical length decreases with increasing surge intensity but increases significantly with greater lightning strike distance. Incorporating an appropriate series inductor can provide the necessary time delay, serving as an alternative to using a long cable. For capacitive loads, although an excessively short cable can reduce the amplitude of oscillatory voltage spikes, it aggravates the surge steepness, thereby stressing the SPD. These oscillations can be effectively suppressed by installing a damping resistor in front of the SPD2. Furthermore, the study reveals a strong coupling between energy coordination and overvoltage behavior under capacitive load conditions, indicating that the two must be jointly optimized. The parameter configurations and practical recommendations presented offer quantitative design guidance for SPD selection, cable layout, and resonance suppression in communication power systems. Full article