Hybrid Configuration Research Articles

Additive manufacturing of hybrid continuous carbon/basalt fiber reinforced composites based on bi-matrix co-extrusion

A novel three-dimensional (3D) printed hybrid continuous fiber reinforced bi-matrix composite is proposed in this paper to improve the flexural fracture energy and the designability of flexural mechanical properties, combining the excellent wettability of thermosetting resin to distinct fibers and the wonderful extrusion forming ability of thermoplastic for nozzle based additive manufacturing (AM). Numerical simulations are conducted by finite element (FE) and peridynamics (PD) models, enabling an in-depth study for the influence of printed hybrid configuration on flexural mechanical properties. The results show that assigning more basalt fibers at bottom effectively enhances the capability of flexural energy absorption, with the maximum enhancement of 126.1% in contrast to single-type carbon fiber reinforced samples. The combination of experimental analysis and numerical simulation has reference significance for structural optimization and failure prediction of hybrid continuous fiber composites printed by co-extrusion process.

Quasi-static axial crushing investigation of filament-wound eco-friendly energy-absorbing glass fiber and jute fiber composite structures

This study conducts a comparative analysis of glass fiber (GF) and jute fiber (JF) as energy-absorbing filament wound eco-friendly structures under quasi-static axial crushing with varying wall thickness, starting with a 2-layer configuration and progressing to 4 and 6 layers. Three primary failure modes, fiber-matrix fracturing, local buckling, and delamination were observed. Both JF and GF 2-layer configurations showed less progressive failure due to their lightweight nature, with crush force efficiency (CFE) of 0.44–0.46 and specific energy absorption (SEA) of 4.4–5.1 J/g, raising considerations for crash scenarios involving human safety. The 4-layer JF configuration demonstrated a significant increase in IPF to 3496 N, effectively restricting buckling and brittle fracture and leading to a higher SEA of 12.61 J/g. In comparison, the GF 4-layer configuration exhibits lower initial peak force (IPF) and SEA values but a higher CFE value of 0.64 at a lower weight of 58 g. The 6-layer JF configuration attains increased stability in load-bearing capacity with a CFE of 0.84 but at the cost of a high weight of 128 g. On the other hand, the 6-layer GF configuration showcases a higher SEA of 10.5 J/g with a moderate CFE of 0.75 and slightly lower weight, suggesting a delicate balance between performance and weight. Visual examination revealed dominant failure modes as local buckling in GF and brittle fracturing in JF configurations. Overall, the 4-layer configurations of JF and the 6-layer configuration of GF composite tubes demonstrate exceptional energy absorption efficiency, suggesting the potential for exploring hybrid configurations to achieve a balanced crashworthiness performance.

Optimized Transverse–Longitudinal Hybrid Construction for Sustainable Design of Welded Steel Plate Girders

I-section girders with different types of steel in the flanges and web (fyf > fyw, respectively) are known as transverse hybrid girders. These have proven to be more economical than their homogeneous counterparts. However, the use of hybrid configurations in the longitudinal direction of the element has yet to be studied. This paper uses optimization techniques to explore the possibility of constructing transverse and longitudinally hybrid (TLH) steel girders. The optimization objective is to minimize the manufacturing cost, including seven activities besides the material cost. The geometrically double symmetric I-girder design subjected to a uniform transverse load is performed using Eurocode 3 specifications. Nine case studies are implemented, varying the element span (L) and the applied load. The results show that establishing various configurations along the length of the element is beneficial. The optimum number of transition points is six, meaning the girder will have four configurations, i.e., one central and three others symmetrically distributed toward each half of the element. The optimum position for the first transition would be at 0.24∗(L/2), the second at 0.40∗(L/2), and the third at 0.60∗(L/2). The optimum extreme configuration is usually homogeneous (fyf = fyw = 235 MPa). The others increase the steel quality in the plates, maintaining hybrid arrangements to reach the central one that usually remains with S700 steel for the flanges and S355 for the web. The study shows that TLH configurations are more effective for elements with larger spans. By applying the formulated design recommendations in a different case study, the manufacturing cost dropped by over 50% compared to the traditionally designed element and by more than 10% relative to the optimized element with a homogeneous configuration. The study’s limitations and encouraging results suggest future lines of research in this area.

Analysis of compliant mechanisms with series and parallel substructures through the ellipse of elasticity theory

Compliant mechanisms with complex hybrid configurations have been designed to meet the requirements of specific applications demanding high performance. Kinetostatic analysis, fundamental at the early stage of design, can become difficult for compliant systems characterized by series and parallel substructures. In the present paper, the ellipse of elasticity method is implemented for the analysis of a compliant mechanism with hybrid topology. Firstly, the ellipses associated to the different flexure hinges, characterized by uniform or non-uniform cross-sections, and by constant or variable initial curvature, are determined. Then, the unique ellipse representing the compliant mechanism is obtained by means of series and parallel compositions. By exploiting the antiprojective polarity properties of the ellipse, the kinetostatic analysis of the compliant system is reduced to a geometric problem with a straightforward solution. Linear and nonlinear finite element analyses and experimental tests are performed to verify the theoretical results.

Design and performance analysis of hybrid electric class 8 heavy-duty regional-haul trucks with a micro-pilot natural gas engine in real-world highway driving conditions

Diesel-fueled heavy-duty (HD) trucks are a key component of global freight transport, but consume 25% of the transportation industry's energy and emitting substantial greenhouse gas (GHG) emissions. Utilizing low-carbon fuels like natural gas (NG), combined with hybridization, presents an excellent opportunity for reducing GHG emissions and fuel consumption. Micro-pilot dual fuel diesel/NG engines offer high engine brake thermal efficiency (BTE) with an efficient three-way catalyst (TWC) to limit pollutant emissions like CO2 without the need for costly exhaust aftertreatment systems. This engine is particularly well-suited for hybridization, as it features high-efficiency under stable, mid-, and high-load conditions, but with reduced performance at low loads. This paper validates two conventional baseline models (X15 Cummins diesel engine and micro-pilot NG engine) based on a tested class 8 regional-haul truck on highway. The study investigates the combined effect of low-carbon fuels and hybridization on improving the fuel economy and GHG emissions of class 8 regional-haul trucks. This involves designing pre-transmission parallel and plug-in hybrid configurations with downsized 6.7-liter micro-pilot NG engines. The cargo load and performance requirements are maintained equivalent to the conventional diesel baseline. Results show comparable fuel economy and engine BTE between conventional diesel baseline and NG models on highways with full cargo load. The parallel and series plug-in hybrid NG designs exhibit fuel economy improvements of 2.9% and 26%, respectively, compared to the micro-pilot NG over highway with full cargo load. In the same conditions, the CO2 emissions reductions for parallel and series plug-in hybrid NG designs are 15% and 51%, respectively, relative to the conventional diesel baseline. In addition, this article provides a detailed comparison and analysis of non-plug-in and plug-in hybrids based on component energy losses and internal combustion engine (ICE) operating points.

Computational studies on hyper velocity impact of spherical projectiles on whipple shield with hybrid Newtonian fluid-filled core

Satellites orbiting in low Earth orbits face potential threats from space debris. To mitigate this risk, a Whipple shield is employed to shield satellites from potential hyper-velocity impacts caused by debris of varying sizes and speeds. Typically, these protective systems use spaced aluminum plates affixed to the satellite’s exterior. Ongoing advancements in this field include exploring alternative materials such as foam, cellular cores, and ceramics to replace aluminum in plate construction. This study introduces a hybrid configuration featuring a Newtonian fluid-filled, high-performance fiber-reinforced polymer core positioned between the aluminum alloy plates, aiming to enhance the Whipple shield’s overall shielding effectiveness. The analysis of hyper-velocity impacts was performed numerically using ANSYS Autodyn® computational software. Spherical projectiles made of stainless steel, ranging in diameter from 2 mm to 4 mm, were selected for direct collision simulations with the Whipple shield at velocities of 5 km/s, 7 km/s, and 9 km/s. The front and rear plates, each 1 mm thick, were constructed using AA6061-T6. The core, measuring 10 mm in thickness, incorporated multiple plies of Kevlar fiber-reinforced polymer (KFRP), with interplay spacing between successive KFRP plies filled with a Newtonian fluid (water). It was observed that spherical projectiles made of stainless steel with diameter ≥ 3 mm penetrated the rear plate of the whipple shield at the lower velocity of 5 km/s, with enhanced damage as the initial velocity of the projectile was increased from 5 km/s to 9 km/s. The debris cloud was found to scatter the fluid droplets, rupture the successive KFRP layers, with the initial kinetic energy playing a significant role in the severity of the damage.

ADVANCED HYBRID SOLAR THERMOELECTRIC GENERATOR THEORETICAL ANALYSES

Due to the fact that much of the world’s best solar resources are inversely correlated with population centers, significant motivation exists for developing the technology, which can deliver reliable and autonomous conversion of sunlight into electricity. Thermoelectric generators (TEG) are gaining incremental ground in this area due to its extensive use in solar thermal application as power generators, known as solar thermoelectric generators (STEG). STEG systems are gaining significant interest in both, concentrated and non-concentrated systems and have been employed in hybrid configurations with the solar thermal and photovoltaic systems. In this dissertation, mainly studies of Hybrid Solar Thermoelectric Generators (HSTEG) configuration are presented. HSTEG systems are much less studied both experimentally and theoretically, despite their clear technoeconomic advantages. There is a scope for significant improvement in the performance (efficiency) and a need for detailed performance analysis to understand the fundamentals of the energy transfer process. HSTEG systems (conventional) reported till date, initially the solar energy is utilized by the TEG for generating electricity and then transferred to other low temperature thermal cycles (heating or cooling). As an alternative one can design an advanced HSTEG system, in such way to first utilize the solar energy in the heat transfer fluid (HTF), which can run high temperature thermal cycle for heating or cooling or power generation) and then generate electricity by using TEG. Further, there is no advanced HSTEG system is available in the literature, which could deliver high temperature heat output from the hot side of the HSTEG system. Key Words: optics, photonics, light, lasers, stencils, journals

Energy absorption and piezoresistive characteristics of 3D printed honeycomb composites with hybrid cell architecture

ABSTRACT This paper introduces a novel hybrid honeycomb (HC) design achieved by continuously blending non-auxetic hexagonal and auxetic re-entrant cell geometries along the out-of-plane direction. These novel hybrid HCs are additively manufactured via fused deposition modelling (FDM) using PA12 polymer reinforced with 15 wt.% of discontinuous carbon fibres. We study the mechanical and piezoresistive performance of hybrid HCs under quasi-static in-plane and out-of-plane loading performed at temperatures ranging between 25-125°C. The results demonstrate significant in-plane compression performance enhancements in the hybrid configuration, achieving up to 43% increase in the collapse strength and 119% in absorbed energy. The incorporation of multiple hybrid layers in the honeycomb structure further enhanced the in-plane properties, ultimately achieving a 181% enhancement in energy absorption. The hybrid honeycombs also showed a pronounced piezoresistive response with gauge factors in the range of 18–37 within the elastic regime, making them suitable for a wide range of multifunctional applications.

Advanced linear axial wavelength spreading through cascaded double hyperchromats

This study explores the design and optimization of cascaded double-hyperchromatic optical systems (i.e., 2×2 lenses), focusing on achieving an extremely linear axial spectral decomposition characterized by an exceptionally low equivalent Abbe number. The investigation involves two double hyperchromats, considering both purely refractive systems and hybrid configurations that combine refractive and diffractive elements. For purely refractive systems, alternating focal length signs of divergent and collective lenses are crucial to achieve significant axial chromatic dispersion. In hybrid systems, the position of the diffractive optical element (DOE) and the selection of focal lengths play key roles in obtaining extremely low equivalent Abbe numbers. The optimized systems demonstrate absolute equivalent Abbe numbers of 0.983 for purely refractive and 0.65 for hybrid systems—more than four times lower than the absolute Abbe number of a single diffractive element. Notably, even systems using standard materials exhibit significantly low equivalent Abbe numbers of 2.5 and 1.4 for pure refractive and hybrid configurations, respectively. These results offer promising opportunities for improving optical applications based on axial spectral decomposition, overcoming previous limitations of axial chromatic spreading.

A Cable-Based Haptic Interface with a Reconfigurable Structure

Abstract Cable robots have been used as haptic interfaces for several decades now, with the most notable examples being the SPIDAR and its numerous iterations throughout the years, as well as the more recent IPAnema 3 Mini manufactured by Fraunhofer IPA. However, these robots still have drawbacks, particularly their high number of cables required to maintain a high workspace-to-installation-space ratio. Using a hybrid-structure cable robot (HSCR) could prevent some collisions that occur between the cables and the user's body. More specifically, some applications requiring multimodal feedback could benefit from the flexibility that a reduced number of cables offers. Therefore, this paper presents a novel SPIDAR-like VSCR and its sensor-less force control method based on motor current. The purpose of this work is to clarify the advantages that a variable structure can provide for haptic interaction. In this regard, experimental results regarding the device's workspace and its force feedback capabilities are presented. Additionally, since real-time high-frequency updates are required for haptic display, we provide additional data regarding the control algorithm's runtime. Lastly, another experiment was conducted to study changes in user performance when using both the variable and the usual cable configuration. The results showed that feedback accuracy is maintained, and there are no drawbacks to using hybrid configurations.

Impact of flow configuration and temperature on water flooding and membrane water content of low-temperature proton exchange membrane fuel cell

Low-temperature proton exchange membrane fuel cells (LT-PEMFCs) have emerged as promising candidates in transportation due to zero-emission, high power density and efficiency. Issues such as liquid water flooding and membrane drying significantly reduce their performance and durability during higher current density operations. Although many simplified 1-D and 2-D models have been proposed, they do not aid in understanding water dynamics and membrane water content for different flow configurations and operating temperatures. This work focuses on the development of a 3-D, multiphase, non-isothermal, physics-based model of the LT-PEMFC to address the above-mentioned issues. The model is validated with experiments performed on a 32 cm2 LT-PEMFC at 40 °C with a hybrid flow configuration. The results suggest that the hybrid configuration provides a power density enhancement of 12 % compared to the parallel configuration at 70 °C. Due to this performance improvement, ΔT of the hybrid configuration has reached 7 °C, which is slightly higher than the parallel configuration's ΔT of 5.7 °C. With an increase in operating temperature from 40 °C to 70 °C, the hybrid configuration experiences a 50% enhancement in the power density. For both temperatures, the hybrid configuration shows a consistent increment in the saturation from inlet to outlet, which creates a favorable pathway for water removal from the cell. The findings from this work suggest that the hybrid configuration is superior to the parallel configuration in terms of power density output, water removal capacity and membrane water content. This work provides valuable insight into overcoming key issues of liquid water flooding and membrane durability.

Investigation on fatigue behavior of GFRP hybrid bonded/bolted joint under shear loading based on nondestructive monitoring test and numerical modeling

The GFRP (Glass Fiber Reinforced Polymer) is prospective in bridge and building engineering for its advantageous material property. The connection configuration of hybrid bonded/bolted joint of GFRP is thought superior in mechanical performance compared with the traditional bonded and bolted joints. However, the fatigue issue of this type of joint remains unclear which impedes its engineering applications. The presented work experimentally and numerically investigated the fatigue behavior of the GFRP hybrid bonded/bolted single-lap joints under shear loading. High-cycle fatigue tests on single-bolt, four-bolt, and nine-bolt specimens were conducted to study the failure process, rigidity degradation, failure mode, and fatigue life of the hybrid joints, where the nondestructive monitoring techniques of AE (Acoustic Emission) and 3D-DIC (Three-Dimensional Digital Image Correlation) were adopted, respectively to detect the material damages and overall deformation of specimens. Finite element modelling was further carried out to reveal the fatigue failure mechanism of hybrid joints, in which the property degradation of GFRP plates and adhesive layer were considered. Results showed that the failure process of GFRP hybrid single-lap joints under fatigue shear loading can be divided into four stages: (1) steady and (2) rapid development of adhesive damage, (3) steady and (4) rapid development of GFRP damage, of which the (2) and (4) stages account for less than 3% of the total fatigue life of joint, respectively. Stiffness degradation of 14–35% were read for the tested joints before final failure, and the joints with more bolts performed a superior degradation resistance compared to the less ones. Besides debonding and bolt inclination, the single-bolt joints failed with bearing failure of GFRP material, while the failure mode of multi-bolt joints were dominated by shear failure in GFRP plate with Y-shaped zone. The simulation results well supported the observations in experimental test. Based on the experimental results, the S-N curve of the GFRP hybrid single-lap joints is proposed, which can provide support for the engineering design of this type of joints.

Enhanced freeze-thaw resilience of cement mortars through Nano-SiO2 and single/hybrid basalt fiber incorporation: Assessing workability, strength, durability

This study investigated how freeze-thaw cycles (FTC) impact concrete durability and structural integrity, exploring novel approaches like integrating nanomaterials and fibers into concrete compositions. After subjecting the materials to FTC, the study evaluated mortars enriched with nano-SiO2 (NS) and micro- and macro-basalt (BA) fibers. NS was incorporated by substituting 1 % and 2 % of the cement content. Meanwhile, 24 mm in length macro-BA fibers were added individually or in hybrid compositions with 6 mm micro-BA fibers at 0.5 % and 1 % volumetric ratios. The results revealed significant improvements in both the strength and durability of mortar specimens post-FTC, attributed to the enhancing properties of NS. Its capacity to fill voids and substantial pozzolanic activity notably improved the material's performance. However, adding BA fibers adversely affected mortar workability, causing a decrease in flow diameters (FD) as the fiber ratio increased.Nevertheless, BA fibers effectively maintained specimen integrity post-FTC despite leading to decreased residual compressive (RCS) and flexural strengths (RFS). This reduction was linked to the robust bonding between BA fibers and the matrix, impeding crack propagation post-FTC. Interestingly, combining BA fibers in hybrid configurations improved workability and significantly enhanced residual strength characteristics, surpassing singular applications. For instance, after 180 FTC, the K0 control specimen exhibited a 34.17 % and 34.56 % reduction in RCS and RFS, respectively. In contrast, the K10 specimen with 2 % NS and a hybrid combination of BA fibers at a volumetric ratio of 1 % displayed notably lower reduction rates of 23.69 % and 16.99 %, respectively.

Optimizing integrated energy systems using a hybrid approach blending grey wolf optimization with local search heuristics

Integrated energy systems play a crucial role in the transition to sustainable energy solutions, requiring a delicate balance between economic efficiency and reliability. Energy storage and demand response are pivotal components for managing power fluctuations and optimizing consumption. This paper introduces a hybrid approach that combines Grey Wolf Optimization (GWO) with Local Search Heuristics (GWOLSH) to achieve optimal energy system configurations. The approach formulates a hybrid energy storage capacity allocation method that considers the needs of wind power companies and users. It begins by constructing load-shifting and load-reduction models based on flexible user-side load response characteristics. In a comparative analysis, GWOLSH exhibits superior performance over WSO and PSO, evidenced by achieving a lower cost reduction of 330,595 USD (GWOLSH) compared to 344,974 USD (WSO) and 350,694 USD (PSO), along with higher percentage improvements in system stability (0.38 % for GWOLSH, 0.39 % for GWO, and 0.40 % for Particle swarm optimization (PSO)) and greater user satisfaction levels (0.8985 for WSOLSH, 0.8930 for GWO, and 0.8928 for PSO). This hybrid configuration proves effective in enhancing both economic efficiency and system reliability, offering a promising solution for maintaining a consistent power supply amid fluctuations, identifying energy system configurations that enhance economic efficiency while bolstering system reliability to ensure a consistent power supply amid fluctuations.

Performance analysis of an idealized Darrieus–Savonius combined vertical axis wind turbine

AbstractTo investigate the effect of force distributions of each turbine component on the power performance of the Darrieus–Savonius combined vertical axis wind turbine (hybrid VAWT), the hybrid VAWT is modeled as idealized turbine under various force distributions. The goal of idealization is to simplify the intricate interactions between the Savonius and Darrieus components. The simulation actuator surfaces with uniform force distributions lead to a cost‐effective way to identify the optimal force distribution of each turbine component. The numerical model was validated against momentum theory. The results demonstrated that the numerical and theoretical results yield similar predictions in the low‐thrust cases but show differences in the high‐thrust cases. The maximum power coefficient of an idealized hybrid VAWT with given thrust coefficient is lower than that of a single actuator. This is a consequence of the nonoptimal loading on the actuator. The results indicate that an idealized hybrid VAWT does not show a significant power increase compared with an optimal single Darrieus rotor. Therefore, the presence of a Savonius rotor inside a Darrieus rotor leads to a lower power output in any circumstance. The hybrid configuration is primarily advantageous for the start‐up performance of the combined rotor, which is not explored in this study.

Sustainable approach for the treatment of dye-containing wastewater – a critical review

Abstract In the world’s rapidly expanding economy, textile industries are recognized as a substantial contributor to economic growth, but they are one of the most significant polluting industrial sectors. Dye-contaminated water sources can pose serious public health concerns, including toxicity, mutagenicity, and carcinogenicity among other adverse health effects. Despite a limited understanding of efficacious decolorization methodologies, the pursuit of a sustainable strategy for the treatment of a wide spectrum of dyes remains a formidable challenge. This article conducted an exhaustive review of extant literature pertaining to diverse physical, chemical, biological, and hybrid processes with the aim of ascertaining their efficacy. It also elucidates the advantages and disadvantages, cost considerations, as well as scalability impediments of the treatment methodologies, thereby facilitating the identification of optimal strategies for establishing techno-economically efficient processes in the sustainable handling of these effluents. The hybrid configuration exhibited superior efficiency and was documented to surmount the limitations and constraints inherent to individual techniques. The study also revealed that most of the proven and established dye removal techniques share a common limitation viz., the generation of secondary pollution (i.e., sludge generation, toxic intermediates, etc.) to the ecosystem.

Theoretical Modeling and Experimental Verification of Elliptical Hyperbolic Hybrid Flexure Hinges

A flexure hinge composed of elliptical and hyperbolic hybrid configurations is developed and analyzed in this paper. The analytical models of compliance, rotation accuracy, and maximum stress of the flexure hinge are established, and the correctness of the models is validated by finite element analysis and experiments. The influence of structural parameters on compliance and rotation accuracy is discussed. The concept of compliance stress ratio is proposed to assess the deformation capacity of flexure hinges when subjected to the same stress, which provides a basis for quantitatively comparing the comprehensive performance of flexure hinges. The performance of the hybrid flexure hinge is compared with that of elliptical, hyperbolic, and circular flexure hinges by taking the compliance accuracy ratio and the compliance stress ratio as the performance evaluation indexes. The results show that the hybrid flexure hinge combines the advantages of hyperbolic and elliptical hinges and has a balanced performance in compliance, rotation accuracy, and low stress. The designed hybrid flexure hinge is suitable for the support structure of fast steering mirrors, which provides a valuable reference for the engineering optimization design of flexure hinges.

Techno-economic feasibility assessment and performance analysis of standalone solar photo voltaic-biomass hybrid system with optimized storage: a case study—Grand Bassa, Liberia

Introduction: Liberia has a significant obstacle in terms of restricted power accessibility, as only 26.7% of its populace have access to electrical energy. To tackle this issue, there is a collaborative effort between the government and private sector to undertake energy projects aimed at enhancing the power supply of the grid. The purpose of this study is to evaluate the techno-economic feasibility and analyze the performance of a standalone biomass/solar photovoltaic (PV) hybrid energy system for a rural Liberian community that mostly relies on traditional biomass.Methods: HOMER pro program was used to configure the system, model the community’s load over a year, and generate the resource data of the location.Results and Discussion: Four different configurations were obtained and analyzed both technically and economically to determine the most feasible configuration. This study has shown that a hybrid configuration incorporating Biomass Gasifier, Solar PV, and Battery storage is more feasible with annual output power of 77104 kWh/yr, LCOE ($/kwh) of 0.29 and NPC ($) of 0.3979 million. If implemented with external funding, it will enhance the education, economic and socio-economic status of rural settlements. The results will serve as a valuable resource for informing choices on the implementation of the hybrid energy solution and guaranteeing its sustained efficacy within the community.

Integrated CFD-FEM approach for external gear pump vibroacoustic field prediction

In this work, a three-dimensional fluid-structural and vibro-acoustics coupled model of a gear pump is presented. Gear pumps represent the majority of the positive displacement machines used for flow generation in fluid power systems. Typically, the dynamics of gear pumps are dependent on the characteristics of the fluid dynamics inside the pump, which translates into vibrations to the housing. These vibrations then propagate to the surrounding medium and emit sound. The purpose of this study is to propose a three-dimensional fully integrated computational model to simulate the complete gear pump behaviour from the fluid dynamics to the structural vibrations, up to the vibroacoustic response. In this hybrid configuration, a transient CFD (Computational Fluid Dynamics) model is first developed to simulate the 3D flow field with a deforming and re-meshing approach to take into account the variation of the volume between the gears. Second, the internal pressure field calculated at each time step is then used as a loading into a structural FEM (Finite Element Method) model of the gear pump to compute the actual stresses and deformations of the housing. Third, the results of the structural response are used as excitation in a vibroacoustic sub-model to simulate the radiated noise using a high-order FEM technique. The comparison between the numerical and experimental flow curves validates the CFD model. The sound power calculations from the vibroacoustic model show good comparison with the sound intensity measurements around the pump casing, confirming the validity of the proposed coupled model. The described CFD-FEM approach proves to be a powerful gear pump design tool: it provides a reliable estimate of gear pump working parameters such as fluid power and vibroacoustic characteristics, starting from the CAD (Computer-Aided Design) geometry of the components. Furthermore, being one of the first multi-domain simulation models of a gear pump, this work can be useful to researchers as a starting point to correlate the noise emitted with the internal flow in full 3D conditions.

Mechanical Properties Characterization of Glass/Carbon Fiber Hybrid Multilayer Composite under Environmental Aging Condition

Metallic components in boating industry are being replaced with carbon fiber composites due to their light weight, excellent mechanical properties, and corrosion resistance. However, the carbon fiber cost has obstructed the substitution. Hybridization is suggested to merge carbon and glass fibers in cost-effective composites while maintaining the desired engineering properties. This study experimentally examines the impact of hybridization and seawater aging on the mechanical properties of glass and carbon fibers hybrid composites. A range of composites ([C]6, [CGC]s, [C]3[G]3, [GCG]s, and [G]6) are fabricated and aged in simulated seawater solution before their tensile, flexural, impact, and hardness properties are examined. The results revealed degradation in properties due to the ageing, the degree of degradation is influenced by the s hybridization configuration. The [G]6 sample shows the highest tensile strength reduction of 30% compared to 20% for the [C]6. The remaining samples exhibit reduction percentages falling between these two extremes. A similar behavior is observed in the flexural test, though the extremes values are smaller, 10.2%, and 12.5%. The impact and hardness tests showed an inverse relationship between the glass fiber content and impact strength degradation due to aging, while they exhibited a linear correlation for hardness degradation due to ageing.