Load Conditions Research Articles

Biomechanical stability of magnesium plate and screw fixation systems in LeFort I osteotomy: a three-dimensional finite element analysis

BackgroundTitanium (Ti–6Al–4 V) is used for fixation in LeFort I osteotomy, a procedure for treating midface deformities. This study assessed the biomechanical stabilities of two Mg alloys (WE43 and ZK60) as biodegradable alternatives and compared them against Ti using finite element analyses. The LeFort I osteotomy procedure was simulated, and various plate and screw configurations were tested. The maximum principal and peak von Mises stresses in the metal plates and bone screws were measured under four load conditions, and the stability was evaluated.ResultsThe holes in the Mg screws, as compared with the Ti counterparts, exhibited higher and lower stress levels in the cortical and cancellous bones, respectively. The Mg screws also exhibited a higher fracture risk. The ZK60 plate, as compared with the Ti and WE43 plates, exhibited a lower fracture risk under all load conditions. ZK60 exhibited higher biomechanical stability in terms of maintaining the gap between osteotomy surfaces and lower fracture risk; the osteotomy surfaces with Ti im-plants underwent bone impaction, resulting in gap closure.ConclusionsAlthough the Mg implants exhibited better stress distribution, their screw strength requires improvement. Appropriate improvements can promote the use of Mg alloys in bone fixation applications.

Stability Analysis of DC Microgrids: Insights for Enhancing Renewable Energy Integration, Efficiency and Power Quality

In the current context of smart grids, microgrids have proven to be an effective solution to meet the energy needs of neighborhoods and collective buildings. This study investigates the voltage behavior and other critical parameters within a direct current (DC) microgrid to enhance system efficiency, stability, and reliability. The dynamic performance of a DC microgrid is analyzed under varying load and generation conditions, with particular emphasis on the voltage response and load-sharing mechanisms required to ensure stable operation. The findings indicate that specific control strategies, particularly droop methods, are effective in mitigating voltage fluctuations, enhancing power quality, and ensuring proper load distribution across multiple sources. This study also addresses significant challenges, including voltage regulation and fault resilience, to provide guidelines for designing robust and efficient DC microgrids. These insights are essential to inspire further advancements in control strategies and facilitate the practical deployment of DC microgrids as a sustainable solution for distributed energy systems, especially in scenarios prioritizing high DC load penetration and renewable energy integration.

Tribological gradients of acid-aged coir and coconut husk powder reinforced LDPE plastic under different normal load conditions for potential applications in oil and gas industries

Tribological gradients of acid-aged coir and coconut husk powder reinforced LDPE plastic under different normal load conditions for potential applications in oil and gas industries

Experimental Investigation into the Influence of Filament Layer Arrangement on the Tensile Strength of FFF-Manufactured Components

One major disadvantage of fused filament fabricated components (FFF) is its well-known anisotropy, which results from the layer-wise adding of material, and that it is not always possible to avoid loading in the layer build-up direction. In particular, components that are exposed to multi-axial load conditions must manage with reduced tensile strength in the build-up direction. This work is therefore concerned with improving the tensile strength transverse to the layering by changing the layer structure without directly changing the material itself. Therefore, the print-defining G-Code was modified to change the arrangement between the layers. The effectiveness of this method was investigated by means of tensile tests using thermoplastic samples made of Acrylonitrile Styrene Acrylate (ASA), Poly Cyclohexylenedimethylene Terephthalate Glycol (PCTG), Poly Ethylene Terephthalate Glycol (PETG) and Poly Lactic Acid (PLA) for layer thicknesses of 0.16 mm and 0.28 mm. The results show that the G-Code modification generally resulted in an increase in tensile strength. For PETG, an improvement of 25% was achieved.

Impact of Optimization Variables on Fuel Consumption in Large Four-Stroke Diesel Marine Engines with Electrically Divided Turbochargers

The objective of this study is to understand how each variable impacts the optimal configuration of a marine diesel engine equipped with an electric hybrid air-charging system that allows energy assistance and recovery. The aim is to minimize CO2 emissions by reducing fuel consumption. The hybrid system offers flexibility in adjusting parameters from both the engine and air-charging system. It is compared with the baseline engine, which uses a free-floating turbocharger. The results show a significant improvement at low engine loads, where the baseline engine struggles to provide sufficient air. While turbine speed has little influence, compressor power reduces fuel consumption at low loads. However, at mid loads, resizing the turbomachine is necessary for further improvements. At high loads, full optimization of all variables is required to reduce fuel consumption. The electric hybrid system is particularly effective in tugboat-like conditions, where low loads dominate, but less impactful for ro-pax ferries. Despite the potential of the hybrid system, a fully optimized turbocharger could provide greater benefits due to reduced losses. Future studies could explore combining the adaptability of the hybrid system with a highly efficient turbocharger to reduce emissions across all load conditions.

A novel tube law analysis under anisotropic external load

Mathematical and physical modeling of flows in collapsible pipes often relates the flow area to the difference between the internal and the external pressures (i.e. the transmural pressure). The relation is used to model the conduits of the human body transporting biological fluids, is called tube law and usually considers the transmural pressure resulting from isotropic external pressure only. We provide a new empirical tube law considering anisotropic conditions of the external load; our formulation is based on the hypothesis, supported by clinical and experimental findings, that in physiological conditions both isotropic and anisotropic stresses are combined in the external load acting on vessels. The proposed mathematical model was validated through laboratory experiments reproducing the flow through a collapsible tube representing the physiological conditions of male urethra during micturition. The proposed tube law better agrees with the experimental observations, in comparison to classic formulations available in literature, thus showing that the proposed model better describes the physiological condition of flow in collapsible tubes subjected to anisotropic external load. The application of our model can be readily extended to several types of vessels.

OC6 Phase IV: Validation of CFD Models for Stiesdal TetraSpar Floating Offshore Wind Platform

ABSTRACTWith only a few floating offshore wind turbine (FOWT) farms deployed anywhere in the world, FOWT technology is still in its infancy, building on a modicum of real‐world experience to advance the nascent industry. To support further development, engineers rely heavily on modeling tools to accurately portray the behavior of these complex systems under realistic environmental conditions. This reliance creates a need for verification and validation of such tools to improve reliability of load and dynamic response prediction and analysis capabilities of FOWT systems. The Offshore Code Comparison Collaboration, Continued with Correlation and unCertainty (OC6) project was created under the framework of the International Energy Agency to address this need and considers a three‐sided verification and validation between engineering level models, computational fluid dynamics (CFD), and experimental results. In this paper, a novel floating offshore wind platform, the Stiesdal TetraSpar, is simulated using CFD under the load conditions defined by Phase IV of the OC6 project. The comparison of these CFD results against the experimental results demonstrated the ability to predict the platform response to waves when imposing the measured wave signals as input. Although validation versus experiment was largely successful, the damping behavior was impacted by uncertainties likely originating from the mooring system and sensor umbilical cable. This extensive comparison effort with multiple CFD practitioners offers insight into best practices to achieve reliable results.

Highly accurate simplification of physics-based electrochemical model of all-solid-state battery for online state of charge estimation

Abstract All-solid-state lithium batteries offer superior energy density and safety features, making them highly attractive for electric vehicles and wearable devices. Original physics-based electrochemical model can effectively simulate the internal electrochemical reactions, but they are difficult to be applied to embedded battery management systems. To facilitate the development of real-time applications based on physical models, this paper proposes a SOC prediction method based on a simplified electrochemical model (SEM). First, the transcendental transfer function is converted to third-order transfer functions using the Padé approximation. The electric field in the mass transfer overpotential is then solved for using average numerical integration method. Then, the proposed SEM method under variable load conditions is verified by comparing to the results from original partial differential equations. The results show that the developed SEM strikes a balance between high fidelity and computational efficiency. By taking into account the concentration of Li+ ions in the solid electrolyte, the estimation accuracy of SOC in the range of 0.1 to 0.3 is significantly improved, compared with prior studies. Strong support is provided for the advanced control design of smart management systems of ASSBs.

Biomechanical study of screw implant angle in reconstruction of tibiofibular syndesmosis injury

To investigate ideal screw implant angle in reconstruction of tibiofibular syndesmosis injury by using a biomechanical test. A total of 24 ankle specimens from adult cadavers were used as the tibiofibular syndesmosis injury model. According to the angle of screw placement, the tibiofibular syndesmosis injury models were randomly divided into groups A (0°), B (10°-15°), C (20°-25°), and D (30°-35°), and the screws were placed at a level 2 cm proximal to the ankle joint. The displacement of fibula was measured by biomechanical testing machine at neutral, dorsiflexion (10°), plantar flexion (15°), varus (10°), and valgus (15°) positions, with axial load of 0-700 N (pressure separation test). The displacement of fibula was also measured at neutral position by applying 0-5 N·m torque load during internal and external rotation (torsional separation test). In the pressure separation test, group C exhibited the smallest displacement under different positions and load conditions. At neutral position, significant differences were observed ( P<0.05) between group A and group C under load of 300-700 N, as well as between group B and group C under all load conditions. At dorsiflexion position, significant differences were observed ( P<0.05) between group A and group C under load of 500-700 N, as well as between groups B, D and group C under all load conditions, and the displacements under all load conditions were significantly smaller in group A than in group B ( P<0.05). At plantar flexion position, significant differences were observed ( P<0.05) between group D and group C under all load conditions. At valgus position, significant differences were observed ( P<0.05) between group A and group C under load of 400-700 N, as well as between groups B, D and group C under all load conditions. In the torsional separation test, group C exhibited the smallest displacement and group B had the largest displacement under different load conditions. During internal rotation, significant differences were observed ( P<0.05) between group B and group C under all load conditions, as well as between group D and group C at load of 3-5 N·m. During external rotation, significant differences were observed between groups B, D and group C under all load conditions ( P<0.05). No significant difference was detected between groups at the remaining load conditions ( P>0.05). The ideal screw implant angle in reconstruction of tibiofibular syndesmosis injury was 20°-25°, which has a small displacement of fibula.

Effective utilization of unidirectional laminates for mass reduction in composite blades of multi-MW wind turbines

In this study, a reduction of 7.8–10.37% in the blade mass was achieved by optimizing the thickness of unidirectional spars in the Sandia 100-m all-glass baseline blade for a 13.2 MW wind turbine. The optimized design still complies with stiffness, strength, buckling, and resonance requirements for two design load conditions (i.e. DLCs 6.2 and 1.4) specified in the IEC 61,400-1 standard for both stationary and spinning blades. A genetic algorithm was utilized to solve the multi-criteria, multi-constraint optimization problem while satisfying the allowable design limits specified by the wind turbine standard. The optimized blade designs demonstrated effective use of unidirectional laminates in the spars but led to increased tip deflection and longitudinal strains along with a decrease in buckling performance and first natural frequency.

Straight and helical plating with locking plates for proximal humeral shaft fractures- a biomechanical comparison under physiological load conditions.

Helical plating is an established method for treating proximal humeral shaft fractures, mitigating the risk of iatrogenic radial nerve damage. However, biomechanical test data on helical plates under physiological load condition is limited. Hence, the aim of this study was to compare the biomechanical performance of helical and straight PHILOS® Long plates in AO12C2 fractures using static and cyclic implant system testing. Helical and straight PHILOS® Long plates on artificial bone substitutes were tested under physiological axial static (n=6) and cyclic loading (n=12). The axial construct stiffness was the main parameter for comparing the biomechanical performance of the two groups. Mimicking a clinical scenario, the helical deformation was performed consecutively by an experienced surgeon using iron bending tools. The torsional angle was determined computationally from 3D-scanning models afterwards. Helical plating resulted in a significantly reduced axial construct stiffness in all test scenarios compared to conventional straight plating (static testing: p=0.012; cyclic testing: p≤0.010). No failure occurred within the range of physiological loading in both groups. Helical plating favors multidimensional deformation of the test sample in lateral-ventral direction under axial loading, resulting in a reduced axial construct stiffness and in an increased interfragmentary movement. No biomechanical failure is to be expected within physiological load boundaries.

Effect of Acrylate Emulsion on the Mechanical and Microscopic Properties of Straw Fiber-Reinforced Cement-Magnesium Slag Stabilized Soil

In order to investigate the mechanism of mechanical performance enhancement and the curing mechanisms of acrylate emulsion (AE) in cement and magnesium slag (MS) composite-stabilized soil (AE-C-M), this study has conducted a comprehensive analysis of the compressive strength and microstructural characteristics of AE-C-M stabilized soil. The results show that the addition of AE significantly improves the compressive strength of the stabilized soil. When the AE content is 0.4%, the cement content is 3%, and the magnesium slag content is 3% (AE4-C3M3), the strength of the formula reaches 4.21 MPa, which meets the requirements of heavy traffic load conditions in the construction of high-speed or main road base layers. Some reactive groups on the polymer side chains (-COOH) engage in bridging with Ca2+ and RCOO− to form a chemically bonded interpenetrating network structure, thereby enabling the acrylate emulsion to enhance the water damage resistance of the specimens. The notable improvement in strength is attributed to the film-forming and solidifying actions of AE, the binding and filling effects of C-S-H gel, and the reinforcing effect of straw fibers. FT-IR and TG-DSC analysis reveals the presence of polar electrostatic interactions between AE and the soil matrix. AE enhances the bonding among soil particles and facilitates the attachment of C-S-H gel onto the surfaces of the straw fibers, thereby increasing the strength and toughness of the material. The application of MS in conjunction with straw fibers within polymer-modified stabilized soil serves to promote the recycling of waste materials, thereby providing an environmentally friendly solution for the engineering application of solid waste.

A Comparative Study on the Wear Resistance of CrNiMo Cast Steels Under Dynamic Load and Ring Block Conditions

Low-alloy CrNiMo cast steels are often used in the caterpillar boards of excavators in mining engineering machinery due to their good mechanical properties and low cost. Three CrNiMo cast steels with different carbon contents (0.20%, 0.29%, and 0.35% by weight) were developed in this work. The mechanical properties of ingots of these cast steels can be optimized by heat-treated quenching and tempering (QT) and surface induction hardening (QTIH). The wear behavior of QT and QTIH specimens was evaluated under dynamic load and ring block conditions. The results show that the QT specimens exhibit a good mechanical performance and wear resistance. Compared to the QT specimens, the wear resistance can be further improved by QTIH treatment. The wear weight loss of QTIH specimens decreased by 42.7% and 73.2% under dynamic load and ring block wear tests, respectively. Additionally, the strength increased while plasticity and toughness decreased with increasing carbon content. Notably, when the carbon content is 0.29%, the CrNiMo cast steel exhibits an excellent combination of strength, ductility, and wear resistance.

Influence of mode and design factors on the temperature condition of automobile drum brakes

The current state of the highway pavement makes it possible to implement prompt transportation operations. These circumstances lead to the movement of vehicles at high speeds, which is impossible without a braking system capable of ensuring high braking efficiency and optimal flow of the process from the standpoint of stability and controllability. One of the main requirements for a modern automatic transmission braking system is the stability of the initial parameters, that is, parametric reliability. Therefore, it is important to have data on the brakes' operating modes and energy consumption. Only with such data is it possible to create a braking system whose output characteristic will be sufficiently stable under conditions of high energy load. Therefore, it is no coincidence that the international methodology for testing the effectiveness of vehicle brakes (UNECE Rule 13) provides for Test I, which is characterized by cyclic braking (urban conditions), and Test II, which is characterized by prolonged braking (mountain conditions). The brake mechanism is the most unstable link of the brake system; one way to increase its efficiency is to ensure sufficient energy capacity, which is limited by the temperature of the friction surface. The object of the study is the question of the equivalence of the change in the drum radius and the width of the friction belt of the brake, taking the invariance of the temperature of the friction surface under the selected test mode as the criterion of equivalence. It is shown that the role of the drum's side wall on the brake's temperature mode under different test modes can also be evaluated on grid thermal models with the involvement of the "Fourier–2 x,y,z" software complex. The effect of the heat transfer coefficient on the temperature mode of the brake due to the consideration of the gap between the drum wall and the wheel rim is shown. Derived formulas for determining the friction belt's equivalent width under the equality of heat flows, masses, and cooling surfaces.

Series Active Power Filter for Power Quality Improvement

The paper discusses the theoretical framework and operating principles of the SAPF, including its control strategies based on instantaneous reactive power theory and synchronous reference frame theory. The design criteria for the SAPF components, such as the voltage source inverter, DC link capacitor, and coupling transformer, are also elaborated to ensure optimal performance. Simulation studies using MATLAB/Simulink are conducted to evaluate the effectiveness of the proposed SAPF under various power quality disturbance scenarios. The results demonstrate that the SAPF effectively compensates for voltage sags, swells, and harmonics, maintaining voltage stability and reducing total harmonic distortion (THD) to within acceptable standards. Additionally, a prototype of the SAPF is developed and tested in a laboratory environment, confirming the simulation results and showcasing the practical feasibility of the solution. The study concludes that the Series Active Power Filter is a robust and versatile solution for power quality improvement in modern electrical distribution systems. Future work may involve exploring hybrid configurations combining series and parallel active filters for comprehensive power quality management and the development of advanced control algorithms for enhanced performance under dynamic load conditions.

Improvement of Engine Combustion and Emission Characteristics by Fuel Property Modulation

The sustainability of diesel engines has come to the forefront of research with the growing global interest in reducing greenhouse gas emissions and improving energy efficiency. The aim of this paper is to support the goal of sustainable development by improving the volatile properties of diesel fuel to promote cleaner combustion in engines. In order to study the effect of diesel fuel volatility on spraying, combustion, and emission, the tests were carried out with the help of the constant volume chamber (CVC) test rig and an engine test rig, respectively. CVC test: A high-speed video camera recorded the spray characteristics of different volatile fuels in a constant-volume combustion bomb. The effects of different rail pressures and ambient back pressures on the spray characteristics were investigated. Engine test: The combustion and emission characteristics of different volatile diesel fuels under different load conditions (25%, 50%, 75%) were investigated in a four-stroke direct-injection diesel engine with the engine speed fixed at 2000 rpm. The test results show that as the rail pressure increases and the ambient pressure decreases, the spray characteristics of the fuels tend to increase; for the more volatile fuels, although reducing the spray tip penetration, the spray projected area and spray cone angle increase, which is conducive to improving the homogeneity of the fuel and air mixing in the cylinder. The improvement of fuel volatility can form more and better-quality mixtures within the ignition delay time (ID), resulting in a 1–2% increase in peak cylinder pressure and a 2–4% increase in peak heat release. For different loads, pre-injection heat release is generated to redefine the ID and combustion duration (CD). Improved fuel volatility effectively reduces carbon monoxide (CO) emissions by about 8–10% and hydrocarbon (HC) emissions by about 13–16%, but it increases nitrogen oxide (NOx) emissions by about 8–11%. Analyzing from the perspective of particulate matter (PM), combined with the aromatic content of volatile fuels, it is recommended to use fuels with moderate volatility and aromatic content under low load conditions, and at medium to large loads, the volatility of the fuel has less weight on particulates and more weight on aromatics, so it is desirable to use the fuel with the lowest volatility and lowest aromatic content of the fuel selected.

Shear Connection Behaviour and Performance of Steel-Concrete Composite Beams under Seismic and Load Conditions: A Finite Element Analysis

Shear Connection Behaviour and Performance of Steel-Concrete Composite Beams under Seismic and Load Conditions: A Finite Element Analysis

A sustainable Response Surface Methodology and Analytic Hierarchy Process - Weighted Aggregated Sum Product Assessment model to Evaluate Performance and Emissions Characteristics of Diesel engine using Clove Oil Biodiesel Blend

Abstract Replacing diesel with biodiesel generally results in a decrease in exhaust emissions like carbon monoxide, hydrocarbon, particulate matter, and carbon dioxide. However, nitrogen oxide emissions show increasing trends. On the other hand, a decrease in nitrogen oxide emissions has been found using various additives with diesel and biodiesel blends. In this work the experimentations are carried out on diesel, B30 (70% v/v diesel+30% v/v biodiesel), and the B30CL1000 (70% v/v diesel+30% v/v biodiesel+1000 ppm clove oil) to evaluate the performance and emissions of diesel engine. The Response Surface Methodology based approach has been applied to evaluate the effect of different engine operating parameters on engine performance and emission while fueled with the B30CL1000 fuel blend. Further, the Analytic Hierarchy Process - Weighted Aggregated Sum Product Assessment method has been applied to identify the optimal setting of the parameters and rank the optimal engine operating range for the B30CL1000 blend. From results, elicited that the accumulation of 1000 ppm of antioxidant (clove oil) additives in the B30 blend resulted in a reduction in the brake-specific fuel consumption by up to 11.5% at higher loads. Brake thermal efficiency increased by 16.3% at low load conditions for the B30CL1000 blend. After that the B30CL1000 blend showed a 2% drop in carbon monoxide emission at higher loads and the decreased nitrogen oxide emission for the B30CL1000 blend has been also reported as 12% at low loads and 2% at higher loads which follows a similar trend as exhaust gas temperature. The 5th experimental run having CR (17), EGR (0%) and Load (12kg) has been ranked as 1.

Enhanced spray-wall interaction model for port fuel injection under medium load conditions

Abstract This study presents an Eulerian-Lagrangian framework for the numerical analysis of spray dynamics, with a focus on droplet movement, spray-wall interactions, and the effects of varying injection parameters associated with port fuel injection (PFI) system. A grid-independent criterion is introduced to optimize mesh analysis for accurate predictions of fuel penetration length. The size distribution of secondary droplets is described using a probability density function, and statistical optimization is subsequently implemented to estimate their mean size. This probabilistic approach enhances the Lagrangian wall film (LWF) model, leading to accurate predictions of the Sauter mean diameter (SMD) at a given radial width ( $$R_\text{{w}}$$ R w ), with results closely matching experimental data. For $$8.0 ~\text {mm} \le R_\text{{w}} \le 24.0 ~\text {mm}$$ 8.0 mm ≤ R w ≤ 24.0 mm , the maximum SMD of 21.67 $$\mu$$ μ m corresponds to $$R_\text{{w}} = 14.0, \text {mm}$$ R w = 14.0 , mm , while the smallest SMD of 12.68 $$\mu$$ μ m is computed for a radial position of $$R_\text{{w}} = 24.0 ~\text {mm}$$ R w = 24.0 mm . The numerical investigation quantifies the role of spray-wall interactions in determining the trajectory of fuel distribution, particularly in the formation of wall films and the relative spatio-temporal diesel concentration (F/A) %. The study explores aspects such as droplet size variations, heat transfer during evaporation, and film behavior under different injection pressures, providing insights into the multiphysical characteristics of spray-wall systems. Near the impingement site ( $$2.0 ~\text {mm} \le R_\text{{w}} \le 4.0 ~\text {mm}$$ 2.0 mm ≤ R w ≤ 4.0 mm ), the plume height ( $$H_\text{{w}}$$ H w ) slightly decreases with an increase in injection pressure. While the CFD methodology in this current work has been primarily developed for automotive engineering sector (PFI engines), it also has potential applications in areas such as additive manufacturing, hydropower engineering, climate science, and environmental engineering.

Proportional resonant controller design with anti-windup for a single-phase solar inverter

This paper introduces a novel control strategy for regulating the output voltage of a single-phase inverter equipped with an LC filter. The proposed method integrates a Proportional Resonant (PR) controller with an anti-windup compensator to address challenges in voltage regulation and system stability. Unlike conventional techniques, this control approach relies on a single measurement from an output voltage sensor, eliminating the need for complex frame transformations and significantly simplifying the control architecture. The innovative use of the PR controller ensures high performance by achieving zero steady-state error for sinusoidal references, making it particularly effective for applications requiring precision and reliability. The anti-windup compensator enhances system robustness by mitigating controller saturation and maintaining stability under varying load conditions. Extensive experimental tests were conducted to validate the proposed method, demonstrating its superior effectiveness and robustness compared to traditional control strategies. Results highlight its ability to achieve fast response times, minimal steady-state error, and consistent performance across a wide range of operating conditions. This control design offers a simplified yet efficient solution for inverter applications, paving the way for improved performance in renewable energy systems, power distribution networks, and industrial automation, where precise voltage regulation is critical.