Search Results (12,597)

Glass fibre-reinforced polymer (GFRP) offers a durable, high-tensile strength alternative to steel rebar in reinforced concrete (RC). However, the inherent lack of ductility in GFRP limits its structural applications, which has led to the development of hybrid GFRP–steel RC systems. The composite nature of these systems requires an accurate understanding of the bond interaction between GFRP rebar and concrete. Existing bond models often fall short of accurately representing the distinct mechanical properties and surface characteristics of GFRP bars, particularly within finite element (FE) analysis environments. To address this gap, the present study proposes a computational method that employs a feedforward neural network (FFNN) trained on experimental data encompassing a specific range of parameters (bar diameters 8–16 mm, concrete strengths 18–50 MPa), including bar diameter, bond length, concrete strength, and cover thickness. Unlike conventional models that typically focus on peak bond strength, the developed FFNN accurately predicts the complete bond–slip relationship. The developed bond model is then integrated into the FE analysis. The simulation results demonstrate strong agreement with experimental data (average R² = 0.93) and effectively capture key behavioral aspects such as crack initiation and propagation. Full article

This paper presents a comparative modeling and analysis of an induction furnace for melting aluminum (Al) and copper (Cu), focusing on their electromagnetic behavior and heating performance. The study employs ANSYS Maxwell software version 16.0 with the finite element method (FEM) to simulate eddy current generation, Joule heating, and current density distribution in the metallic workpieces. The effects of coil geometry, input current, and operating frequency (50–100 kHz) on heating efficiency and skin depth are investigated. Estimated heating times based on ohmic losses are provided, revealing significant differences between aluminum and copper due to their distinct electrical and thermal properties. The results demonstrate that higher frequencies concentrate heating near the surface, reducing skin depth, while copper exhibits more uniform heating than aluminum. These findings offer practical insights for optimizing induction furnace design and operation for different non-ferrous metals. Full article

This paper presents a novel integrated gear drive unit (IGDU), which integrates a high torque density flux-focusing magnetic gear with a V-shaped interior permanent magnet (IPM) motor into a compact structure. The proposed configuration enables direct torque amplification and efficient low-speed, high-torque operation, addressing the inherent torque limitations of conventional electric motors. Critical design parameters, including pole-pair selection, modulation ring dimensions, and stator slot openings, are optimized to enhance torque performance and minimize cogging torque. Finite element analysis (FEA) verifies a maximum torque output of 43.7 Nm. A prototype of the proposed IGDU was fabricated, and experimental validation confirms the effectiveness of the design, with a good match between the measured back-EMF and the simulated one. The results highlight the potential of the proposed machine for compact, high-performance applications such as electric vehicles and industrial drives. Full article

The inner frame is a primary load-bearing component of an airborne electro-optical pod, and its structural mechanical characteristics directly influence imaging quality and attitude stability under complex operating conditions. During the early design stage, structural assessment mainly relies on high-fidelity finite element analysis (FEA), which is computationally intensive and inefficient for rapid parameter screening and scheme comparison. To address this issue, a simplified analytical method for preliminary evaluation of the inner-frame structure is proposed, and its engineering applicability is systematically assessed. The relationship between inner-frame axis rotation and structural loading conditions is first established. Under the assumption that the loading direction is approximately perpendicular to the curvature direction, curved frame members are equivalently modeled as straight beams of equal length, and analytical expressions for bending deflection are derived. Finite element simulations are then performed to evaluate the accuracy and applicability of the method under different structural parameters. Results show that when curvature and geometric conditions satisfy the limits defined in this study, the deviation between the simplified model and numerical results remains within an engineeringly acceptable range. The method provides an efficient analytical tool for rapid structural evaluation in the early design stage. Full article

High-temperature superconducting (HTS) technologies continue to advance as promising solutions for large-capacity rotating electrical machinery. However, the cryogenic architecture required to maintain superconducting states remains a critical design challenge, particularly for performance evaluation systems (PESs). Conventional helium–neon (He–Ne) circulation-based cooling enables stable low-temperature operation and has been experimentally validated in previous PES implementations, but it introduces substantial limitations due to installation complexity, flow-induced instability, and limited adaptability to different coil configurations. To address these constraints, this study proposes a conduction-cooled PES architecture optimized for HTS field coil testing and examines its thermal and structural characteristics through comprehensive design and finite element method (FEM)-based analysis. A multi-stage conduction cooling pathway using a cryocooler, thermal straps, and copper heat plates was designed to achieve uniform temperature distribution and reduce thermal gradients across the HTS winding. Three-dimensional FEM simulations were performed to evaluate the steady-state temperature distribution and heat-transfer characteristics of the proposed conduction-cooled PES under representative thermal load conditions, and the predicted cooling performance was comparatively assessed against the He–Ne cooled PES. The conduction-cooled PES was analyzed by comparing its predicted performance with previously obtained experimental results from the He–Ne cooled PES. The proposed conduction cooling architecture achieved a significant reduction in total heat load, decreasing from 177 W in the He–Ne system to approximately 78 W in the conduction-cooled configuration while also improving thermal efficiency and simplifying system integration. In addition, conduction cooling enhances compatibility with a wider range of HTS coil geometries by eliminating the constraints associated with fluid-based circulation. While the proposed conduction-cooled PES has not yet been physically fabricated, the numerical framework was established based on experimentally confirmed operating conditions of the previously implemented He–Ne-cooled PES, and future work will include fabrication and experimental validation of the conduction-cooled configuration. These findings demonstrate that conduction cooling represents a practical and scalable alternative for next-generation PES platforms and provide essential design guidelines for the development of high-field HTS coils and large-capacity superconducting rotating machines. Full article

In side-impact collisions, the occupant in the non-impacted far-side position faces a high risk of death and serious injury. However, current research on injury to far-side occupants remains limited. This study utilized 40 real-world side collision cases to extract dynamic boundary condition parameters of the impacted vehicle through kinematic reconstruction. These parameters were input into a simplified finite element (FE) vehicle model equipped with a human body FE model in the far-side position. Simulation calculations were performed to obtain head and chest injury parameters for the far-side occupant and assess their injury risk. Finally, the study focused on analyzing the effect of vehicle motion boundary conditions on far-side occupant’s injury risk. The assessment based on the head injury criterion HIC₁₅ shows a low head injury risk for the far-side occupant. However, using the BrIC metric, which accounts for head rotational motion, reveals a significant risk of severe traumatic brain injury in some cases. Regarding chest injury, analysis based on the effective plastic strain of ribs indicated a low risk of rib fractures. However, results from the chest viscosity criterion (VC) and internal organ strain analysis suggested a high risk of soft tissue injury in the chest. This computational investigation, leveraging biofidelic human models, underscores that the human body’s response to complex, multi-directional impacts is not fully captured by traditional metrics. This study concludes that addressing the protection of the far-side occupant is essential in side-impact safety design, with particular emphasis on the unique injury risks posed by vehicle rotational motion, potentially inspiring biomimetic safety systems that better adapt to these complex loading conditions. Full article

Background/Objectives: Sagittal split ramus osteotomy (SSRO) is a widely used method in the treatment of mandibular deformities. However, high parafunctional forces associated with bruxism can negatively affect stability at the osteotomy site. Botulinum toxin A (BoNT-A), which reduces masseter activity, is considered an additional approach to controlling these forces. Methods: In this comparative finite element study, five different fixation configurations were created on a three-dimensional mandibular model and evaluated under identical boundary conditions using both a 1000 N bruxism-related parafunctional loading and a standardized force-reduction scenario. The stress distributions and displacement amounts on the cortical bone, screws, and plates were examined in each model. Results: The stress distribution was more balanced in the model with double plates, whereas the stress and displacement values were found to be greater for fixations with single plates and only bicortical screws. Under the standardized force-reduction scenario, lower stress and displacement values were observed across all the models. Conclusions: Among the evaluated fixation configurations, the double-plate model demonstrated the most balanced stress distribution. Under the standardized force-reduction scenario, lower stress and displacement values were observed across all the models; these findings reflect the load sensitivity of the fixation constructs and should not be interpreted as evidence of clinical efficacy. Full article

The dynamic behavior of the DS306 detacher, a critical component in industrial fiber processing lines, plays a decisive role in maintenance performance and overall operational reliability. This study introduces a strengthened preventive maintenance strategy that leverages vibration analysis and dynamic modeling with a strong emphasis on early fault anticipation. A detailed numerical finite element model of the detacher was developed to determine its natural frequencies, critical modes, and dynamic response under real operating conditions. Experimental vibration measurements were conducted to validate the numerical model and identify characteristic frequencies associated with imbalance and wear. The results show that the proposed predictive framework not only reproduces the machine’s dynamic behavior with high accuracy but also anticipates mechanical degradation trends well before the occurrence of critical failures. This early-warning capability allows maintenance teams to plan interventions proactively, significantly reducing unexpected downtime, avoiding cascading damage, and improving long-term equipment availability. Overall, the study provides a robust and practical methodology for dynamic diagnosis, fault prediction, and optimized preventive maintenance in industrial rotating machinery. Full article

The traditional analysis of the mechanical performance of steel fiber-reinforced concrete (SFRC) predominantly relies on the assumption of an ideally random fiber distribution. This approach fails to account for the significant distribution inhomogeneity caused by practical construction processes like vibration, creating a discrepancy between simulation and reality. To address this, the main aim of this study was to demonstrate the critical impact of realistic fiber distribution on mechanical behavior by integrating image recognition with meso-mechanical simulation. Multi-factor controlled experiments were conducted to investigate the influence of vibration energy, fiber content, and aggregate volume fraction. An image recognition method was developed to accurately characterize the real spatial distribution of fibers, and these data were used to construct a three-dimensional meso-scale finite element model. Compared with the traditional model assuming random distribution, the proposed model based on the actual distribution showed significantly improved agreement with experimental results in terms of crack propagation paths and reduced the prediction error of the initial cracking load by more than 16.3%. For practitioners, the key takeaway is that modeling based on the actual fiber distribution is crucial for achieving realistic simulations. Our work provides a validated methodology to incorporate real distribution data, thereby improving the reliability of numerical assessments for SFRC structures, rather than relying on idealized random distribution assumptions. Full article

To investigate the dynamic response and failure mechanism of tempered glass subjected to falling-ball impact, a controlled falling-ball impact experimental platform was established. Strain gauges were arranged at multiple locations on the glass surface to capture the transient strain responses under different impact conditions. Based on the experimental setup, a finite element model of tempered glass was developed using Abaqus to simulate the impact process and stress-wave propagation behavior. The experimental results show that falling-ball impact induces pronounced transient strain responses in tempered glass, with strain amplitudes decreasing as the distance from the impact center increases. The strain responses also exhibit clear vibration attenuation characteristics due to energy dissipation and boundary effects. The numerical simulation results are in good agreement with the experimental strain–time history curves in terms of peak strain, temporal evolution, and attenuation trends, confirming the reliability of the numerical model. Further analysis indicates that stress waves generated at the impact point propagate radially within the glass plate and undergo reflection and superposition at the boundaries, leading to localized stress amplification. When the impact energy exceeds a critical threshold, the induced stress surpasses the strength limit of tempered glass, resulting in structural failure. The findings provide theoretical and experimental support for the impact-resistant design and safety assessment of tempered glass. Full article

With the increasing integration of regional energy systems, the dynamic coupling characteristics of cooling, heating, and power flows have become significantly pronounced. However, traditional scheduling models often utilize steady-state assumptions that neglect the thermal transmission delay of the pipeline network, leading to spatiotemporal mismatches between energy supply and load demand. To address this issue, this paper proposes an optimal operation strategy for regional Combined Cooling, Heating, and Power (CCHP) systems that explicitly integrates thermal inertia. First, a Pipeline Fluid Micro-element Discretization Method (PFMDM) is developed based on the Lagrangian specification to accurately characterize the dynamic flow and thermal decay processes without the heavy computational burden of partial differential equations. In addition, the accuracy of PFMDM is directly benchmarked against a high-fidelity transient PDE solver (finite-volume TVD–MUSCL scheme) over a wide range of pipe lengths, flow velocities, and thermal loss coefficients, where the outlet-temperature RMSE remains below 0.2 °C. This model quantitatively reveals the “Virtual Energy Storage” (VES) mechanism of the pipeline network. Second, to overcome the “curse of dimensionality” in dynamic scheduling, a Load-Gradient-Based Adaptive Temporal Discretization (LG-ATD) method is proposed. This method maintains a fine-grained baseline for electrical settlement while dynamically aggregating thermal/cooling steps based on load fluctuations. Simulation results demonstrate that the proposed strategy corrects the significant physical deviations of the traditional steady-state model. The analysis reveals that the steady-state model underestimates the required heating and cooling supply capacities by up to 26.66% and 39.15%, respectively, due to the neglect of transmission losses and delays. By leveraging the VES mechanism, the proposed method enables a fuel-shift in the energy-supply structure, substantially decreasing the electricity purchasing cost (by 75.2% in the tested case). This reduction reflects a reallocation from grid purchases to on-site gas-fired cogeneration to maintain physical feasibility under delay and loss effects, and therefore, it is accompanied by an increase in natural gas consumption and a higher total operating cost. Furthermore, the LG-ATD method significantly alleviates the computational burden by substantially compressing the presolved model size and reducing the overall solving time by more than 80%, thereby effectively mitigating the curse of dimensionality for practical engineering applications. Full article

To address the issues of displacement and insufficient positional stability observed in the clinical use of the PROPEL Mini stent, this study investigates the influence of different biodegradable materials on the mechanical properties of the stent under the constraint of a fixed monofilament braided closed-loop geometry. Finite element analyses are conducted using Abaqus/Explicit to quantitatively evaluate the nonlinear mapping between nominal diameter, axial length, and radial pressure throughout a loading–unloading cycle. The results reveal that while axial behavior is consistent during compression, material-specific plasticity causes irreversible geometric sets in Mg alloy and PLGA models, whereas the PCL stent achieves total elastic recovery to its initial dimensions. During unloading, the Mg alloy stent recovers to a nominal diameter of 28 mm with a reduced axial length of approximately 22 mm, whereas the PLGA stent exhibits a much smaller recovery diameter of 14 mm with an axial length of approximately 23 mm. These post-release configurations directly determine the functional expansion range of the biodegradable stents after implantation. During unloading, the Mg alloy stent provides the highest radial pressure (peak 6.8 kPa) with a functional recovery range up to 26.5 mm, ensuring superior scaffolding stability. In contrast, while PCL achieves the widest recovery (52 mm), its radial pressure is clinically negligible (the maximum value is still less than 165 Pa), and the PLGA model exhibits both insufficient support and a restricted functional recovery limit (13 mm). By using high-strength materials such as Mg alloys, the radial anchoring force of the stent can be effectively enhanced without changing the existing structure, providing a scientific basis for solving clinical displacement problems. Full article

In order to increase the torque of the permanent magnet synchronous machine (PMSM), this paper proposes a novel strategy focusing on the new concept of an additional rotor—referred to as the axial rotor—to effectively utilize the space in PMSMs with distributed windings while preserving the conventional stator slot geometry and winding configuration. Unlike the main radial rotor, which employs radially magnetized permanent magnets (PMs), the proposed axial rotor-based technique uses axially magnetized PMs to highly enhance the magnetic field within the air gap, leading to increased torque output as well as well-suited for transportation applications for transportation sector applications. Moreover, this paper develops a magnetic equivalent circuit (MEC) model so as to facilitate faster design iterations and reduce computational effort as well. The accuracy of the proposed model is validated through Finite Element (FE) analysis and also the proposed design strategy is compared with other configurations. Experimental results further validate the effectiveness of the proposed structure. Full article

Thin-tile vaults, characterized by a wide variety of geometric configurations, represent an important part of the architectural heritage in Southern Italy. Many of these structures are still in serviceable condition. However, the absence of dedicated design guidelines and the need to comply with modern safety and serviceability requirements make their assessment and conservation a challenging task. The present study contributes to a more informed and responsible approach to these historic systems by addressing current normative limitations and by clarifying the structural role of construction elements such as counter-vaults and stiffening ribs. The research focuses on a representative case study located in Sicily, where this technique was extensively used from the late eighteenth century. The investigation combines direct on-site surveys, laboratory characterization of collected material samples, and numerical analysis based on finite-element elastic modeling. The results show that the traditional building knowledge, commonly described as the art of good manufacturing and transmitted through long-standing craftsmanship, produced a construction technique that still fulfills its structural function with remarkable effectiveness. Full article

Designing structure-preserving numerical schemes for the generalized Poisson-Nernst-Planck (PNP) system is challenging due to its inherent strong nonlinearity and coupling. In this paper, we propose a class of efficient, unconditional energy-stable schemes based on the Stabilized Scalar Auxiliary Variable (S-SAV) framework combined with the finite element method. We construct both first-order (BE-S-SAV) and second-order (BDF2-S-SAV) fully discrete schemes. A distinguishing feature of our approach is the use of a linear decomposition strategy, which decouples the complex nonlinear system into a sequence of linear, constant-coefficient elliptic equations at each time step. This significantly reduces computational complexity by avoiding expensive nonlinear iterations. We provide rigorous theoretical proofs demonstrating that the proposed schemes are unconditionally energy stable and strictly preserve mass conservation. Numerical experiments satisfy the theoretical analysis, confirming optimal convergence rates and demonstrating robust preservation of mass conservation and modified energy stability in the tested regimes. Full article