Purpose This study investigates the influence of thermal radiation on the free convection flow of a Jeffrey fluid over a vertical stationary plate. To account for memory and non-local effects in the transport process, the Atangana-Baleanu fractional derivative in the Caputo sense is incorporated into the mathematical model. Design/methodology/approach The governing fractional differential equations are solved analytically using the Laplace transform technique. To further validate and predict the obtained solutions, an Artificial Neural Network (ANN) based on the Levenberg–Marquardt Scheme (LMS-NNA) is developed and trained using the analytical results. Findings The results indicate that thermal radiation significantly enhances the temperature distribution by approximately 12%, while the fluid velocity decreases by about 9% because of the increased thermal resistance and effective viscosity within the boundary layer. The ANN model accurately reproduces the analytical solutions, achieving a maximum prediction error of (10−7) and a regression coefficient ((R)) of 0.9999, demonstrating excellent predictive capability. Originality/value The study combines the Atangana-Baleanu fractional derivative with an ANN-based prediction framework to analyze Jeffrey fluid flow under thermal radiation. This integrated approach provides highly accurate solutions while offering an efficient computational framework for analyzing fractional transport phenomena. The findings contribute to the understanding of radiative heat transfer in non-Newtonian fluids and may be useful in the design and optimization of advanced thermal management and energy-related engineering systems.
Purpose The combined effect of graphene and ceramic reinforcements on the mechanical properties, microstructural characteristics, strain-hardening behavior and Hollomon parameters of AA2024 hybrid composites was systematically investigated. Design/methodology/approach A hybrid metal matrix composite based on AA2024 reinforced with graphene (Gr), zirconium oxide (ZrO2) and boron carbide (B4C) was fabricated using the stir-casting technique. Three compositions A2024 + 0.5 wt.% Gr + 1.25 wt.% ZrO2 + 2 wt.% B4C (Sample 2), AA2024 + 1.0 wt.% Gr + 2.50 wt.% ZrO2 + 2 wt.% B4C (Sample 3) and AA2024 + 1.50 wt.% Gr + 3.75 wt.% ZrO2 + 2 wt.% B4C (Sample 4) were compared with unreinforced AA2024 (Sample 1). Findings Sample 4 exhibited the optimum mechanical performance, with yield strength, ultimate tensile strength, flexural strength and hardness increasing by approximately 26.8%, 18.4%, 58.4% and 33.0%, respectively. The Hollomon strength coefficient (K) increased from 733.64 ± 10.19 MPa to 866.09 ± 21.98 MPa, while the strain-hardening exponent (n) decreased from 0.1357 ± 0.00373 to 0.1147 ± 0.00406, indicating enhanced resistance to plastic deformation. However, elongation and impact strength decreased by 50.5% and 54.6%, respectively, confirming the strength–ductility trade-off. Scanning electron microscope (SEM)/Energy dispersive X-ray spectroscopy (EDS) analyses confirmed homogeneous reinforcement distribution and strong interfacial bonding, while Abaqus predictions agreed with experiments within 1–2% at higher plastic strains. Originality/value This study presents the first systematic investigation of the influence of ternary Gr–ZrO2–B4C hybrid reinforcements on the Hollomon constitutive parameters of stir-cast AA2024 composites by integrating comprehensive experimental characterization with validated Abaqus finite element modeling.
Purpose This work develops a new fractional photo-thermoelastic model to investigate acoustic wave propagation in a damaged magneto-porous microelongated semiconductor medium under hydrodynamic interactions. The study focuses on clarifying the combined influence of fractional thermal memory and material damage on the coupled thermal, mechanical, carrier-density, and acoustic responses of porous semiconductors subjected to photo-thermal excitation. Design/methodology/approach A two-dimensional mathematical formulation is established by coupling generalized thermoelasticity, poroelasticity, microelongation theory, carrier transport, and magneto-hydrodynamic interactions within a damaged semiconductor framework. A single Caputo fractional-order parameter is introduced into the heat conduction equation to characterize memory-dependent thermal diffusion, while the damage parameter is incorporated into the constitutive relations to represent material degradation and stiffness reduction. The governing equations are transformed into ordinary differential equations through the normal mode technique, and analytical solutions are obtained under suitable boundary conditions. Numerical computations are carried out for porous silicon material to evaluate the distributions of temperature, stress, acoustic pressure, carrier concentration, displacement, and microstretch fields. Findings The obtained results demonstrate that the fractional-order parameter strongly affects the attenuation, phase delay, and propagation speed of thermoelastic and acoustic waves. Lower fractional-order values generate pronounced memory effects and smoother thermal responses, accompanied by significant reductions in stress and acoustic amplitudes. Moreover, material damage weakens the elastic resistance of the porous semiconductor and accelerates wave attenuation, particularly in the acoustic and carrier-density fields. The combined action of magnetic field, hydrodynamic interaction, and fractional thermal memory produces highly dispersive coupled wave behavior within the damaged microstructured medium. Originality/value The novelty of this study lies in presenting a unified fractional thermoelastic acoustic model for damaged magneto-porous microelongated semiconductors with hydrodynamic effects. Unlike previous formulations, the proposed model incorporates both fractional thermal memory and damage-dependent constitutive behavior within a coupled photo-thermoelastic semiconductor framework. The developed model provides useful insights for the analysis and design of nanoscale semiconductor devices, acoustic sensing systems, porous optoelectronic structures and laser-based thermal technologies.
Purpose Metaheuristic algorithms often suffer from premature convergence and poor population diversity when solving complex optimization issues. This study aims to develop an improved hybrid algorithm to balance global exploration and local exploitation, and adapt it to multi-objective constrained engineering optimization. Design/methodology/approach A Marsh Wren-Cuckoo Search algorithm is proposed by combining marsh wren decoy nest mechanism and cuckoo Levy flight strategy. Non-dominated sorting and crowding distance are adopted to construct its multi-objective version. Comparative experiments are carried out on standard benchmark functions and CEC-2022 test functions, with mainstream intelligent algorithms chosen as contrast models. Multiple indexes and statistical tests are used for performance assessment, and an I-beam design case is applied for practical verification. Findings The presented algorithm greatly restrains premature convergence and acquires superior convergence precision and stability. Statistical results prove its competitive performance. The multi-objective variant performs well on constraint engineering optimization tasks. Originality/value This work innovatively fuses two biological behaviors to maintain population diversity without losing convergence speed. It provides a reliable optimization tool for practical complex engineering design problems.
Purpose The main theme of this research is to explore the mechanism of Jeffrey hybrid nanofluid flow induced by a nonlinear elastic stretched cylinder influenced by couple stress, thermal radiation and exothermic chemical reaction. Design/methodology/approach The equations of physical problem are transmuted as nonlinear ordinary differential equations by the implementation of suitable similarity transformations. Bvp4c solver is utilized for the computations of problem solutions. The results are validated by the Bayesian Neural Network approach which predicted the superior accuracy with small mean squared error to assure the resistance in deformation. Findings Critical findings indicated that an increase in the magnetic parameter reduced the velocity of the fluid. The incorporation of nanoparticles and thermal radiation remarkably improved the temperature of the fluid. Entropy generation increases with a rise in magnetic field and Brinkman number. It is observed that the friction factor increased by 2.25% when the couple stress parameter increases from 0.5 to 3. Heat transmission rate is augmented by 44.5% by enhancing the thermal radiation parameter from 0 to 1. Practical implications This model will be beneficial in the applications of solar thermal collectors, cooling systems and cooling of nuclear reactors where the solutal and thermal transportation with minimized entropy formation is required for system performance and energy efficiency. Originality/value This study is original and no similar research has been conducted to date.
Purpose This study numerically investigates the three-dimensional, unsteady mass and heat transfer behavior of tri-hybrid nanofluids over a rotating permeable disk. The nanofluid consists of single-walled carbon nanotubes, silver (Ag), alumina (Al2O3) and water (H2O) as base fluid. Effects from a heat source, chemical reaction, thermal radiation and magnetic field are incorporated. Design/methodology/approach The governing equations are transformed into ordinary differential equations using similarity transformations and are numerically solved via the finite element method. Graphs illustrate the impacts of the various influencing parameters, such as stretching ratio, chemical reaction, heat source, radiation, unsteadiness, porosity, magnetic parameters and nanoparticle volume fractions (?1, ?2, ?3) on axial and tangential velocity profiles, temperature and concentration distributions. Findings Tables present their influences on Sherwood number, heat transfer rates and velocity gradients. Key results show that temperature profiles in the tri-hybrid nanofluid increase with higher values of (?1, ?2, ?3). Originality/value The work presented in this article is original.
Purpose To address the critical challenges in reliability analysis of complex systems with high-dimensional nonlinear implicit performance functions including prohibitive computational costs, inefficient failure boundary exploration for small failure probability events, and the accuracy efficiency trade-off in surrogate models. Design/methodology/approach First, an adaptive partitioned Sobol sampling (APSS) strategy is proposed to enhance the exploration capability and uniformity of initial samples, efficiently probing failure boundaries while maintaining computational feasibility. Second, an expected uncertainty (EU) learning function is developed to adaptively refine surrogate models near failure interfaces with minimal function evaluations. Third, an active learning kriging (AK) method incorporating composite stopping criteria is designed. Finally, the proposed APSS framework is embedded into the enhanced surrogate model to assess reliability, achieving an optimal balance between accuracy and computational efficiency. Findings Numerical examples and engineering case studies demonstrate that the proposed approach reduces computational costs while maintaining controlled error levels compared to traditional methods. These results validate the method’s robustness in handling high-dimensional nonlinear implicit performance functions and small failure probability events, providing an engineering solution for the reliability-driven design of complex systems. Originality/value The proposed AK-APSS-EU framework addresses the challenges of small probability events and multiple failure regions by leveraging APSS to generate critical samples across the entire failure domain. By integrating a novel EU learning function with a composite stopping criterion, the method dynamically augments sample points to precisely refine the surrogate model at the failure boundary. Consequently, the framework rapidly approximates the true failure boundary without relying on complex conditional sampling or design point data.
PurposeThis study aims to experimentally and statistically investigate the effects of cutting speed and alloy type on energy consumption and carbon footprint during the bandsaw cutting of AZ31, AZ61 and AZ91 magnesium alloys. By evaluating specific energy consumption (SEC), specific cutting energy consumption (SCEC), carbon footprint (CF) and specific carbon footprint (SCF), the study seeks to identify the most energy-efficient and environmentally favourable cutting conditions. The findings aim to provide a scientific basis for optimizing primary cutting operations of magnesium alloys and to support the development of sustainable manufacturing strategies in the lightweight alloy processing industry.Design/methodology/approachBandsaw cutting experiments were conducted on AZ31, AZ61 and AZ91 magnesium alloy bars (50 mm diameter) under dry conditions at three cutting speeds (19, 28 and 50 m/min) with a constant feed rate of 1 mm/s. Electrical power consumption was continuously monitored using a calibrated current measurement device. The cutting cycle was divided into three stages - blade advancement, cutting, and retraction - to enable stage-based energy analysis. SEC, SCEC, CF and SCF were calculated for each condition. Analysis of variance (ANOVA) and response surface methodology (RSM) were applied to evaluate the statistical significance of cutting speed and alloy type.FindingsCutting speed was identified as the dominant factor influencing all response variables, accounting for approximately 80% of the total variance, while alloy type contributed approximately 20%. SEC values ranged from 11.244 J/mm3 (AZ31, 19 m/min) to 17.378 J/mm3 (AZ91, 50 m/min), and CF values ranged from 3,296 to 5,094 mg CO2e - an overall increase of approximately 55%. AZ91 consistently yielded the highest energy consumption and carbon emissions due to its elevated aluminium content. RSM models achieved R2 = 98.21%, confirming high predictive accuracy. A sensitivity analysis confirmed that conclusions remain robust across different emission factor scenarios. AZ31 at 19 m/min represents the most energy-efficient and environmentally favourable condition.Originality/valueTo the best of the authors' knowledge, this is the first study to comprehensively evaluate SEC, SCEC, CF and SCF during bandsaw cutting of AZ31, AZ61 and AZ91 magnesium alloys under identical cutting conditions. Unlike previous studies focussing on conventional machining processes, this work addresses the largely unexplored area of energy consumption and carbon footprint in primary bandsaw cutting operations. The combined application of ANOVA, RSM and emission factor sensitivity analysis provides a statistically validated and practically applicable framework. The findings offer manufacturers clear guidance for selecting energy-efficient cutting parameters and alloy grades in sustainable lightweight alloy processing.
PurposeTo address the requirement for long-duration and uniform heating of the aero-engine casing specimen in the thermo-mechanical coupling test, the design of high-temperature environment simulation device was developed using a simple and cost-effective heating wire heating method.Design/methodology/approachBased on engineering experience, the initial heating scheme for the specimen was determined, which was then simulated by the finite element method and finally validated through experiments for its feasibility. Joule heating effect was employed to achieve coupling between the electrical and thermal fields, thereby achieving their interaction by finite element simulation. The wound heating wire was modeled by an equivalent method. Radiation and convection were considered the primary heat transfer mechanisms, and the influence of electrical current parameters on the heating effect was investigated. By integrating simulation and experimental verification, the heating scheme was further optimized.FindingsThe results show that the finite element method can accurately predict the heating effect of the heating wire. Uniform and long-duration heating of engine casing can be achieved by regulating the current. The initial heating design meets the test requirements, while the optimized scheme yields a temperature field with better uniformity.Originality/valueAn equivalent three-dimensional model of the wound heating wire was established, which provides an efficient and accurate prediction method for the high-temperature environment simulation device with heating wire and lays a solid foundation for the thermo-mechanical coupling finite element simulation.
Purpose The objective of this research is to boost renewable energy efficiency by employing hybrid nanofluid-assisted heat transfer, utilizing experimental data related to graphene oxide/ionic nanofluids (GO/INF) with a new mathematical model. Design/methodology/approach This study aims to enhance renewable energy efficiency through hybrid nanofluid-assisted heat transfer, using experimental data on GO/INF. The Ionic liquid (IL), Water (H2O) and Graphene Oxide (GO) are used in different ratios to perform hybrid nanofluids. The simulation is carried out with a Control Volume Finite Element Method (CVFEM) that offers high precision, and analytical comprehension is obtained through the Homotopy Analysis Method (HAM). Maintaining the flow stability while moving over the inclined plane is made possible by the porous and variable nature of the flow medium. Findings Water, IL in the ratio 25% and 75% with GO (H2O-IL (25%–75%)-GO) hybrid nanofluid show the highest heat transfer rate, followed by H2O-IL (50%–50%)- GO and H2O-GO. The improvements in thermal performance are calculated 9.001%, 36.6%, 72.8% respectively. These results match experimental data and confirm that GO-INF hybrid nanofluids enhance energy transport, which makes them best for solar applications. Originality/value The combination of variable porous space, non-Fourier heat conduction and stagnation point flow over an inclined plane for heat transfer analysis are novel contribution.
Purpose The aim of this research is to analyse the heat transfer phenomena in steady two-dimensional mixed-convection magneto-hydrodynamics (MHD) flow of a coupled hybrid nanofluid over a nonlinear stretching/shrinking surface with temperature-dependent viscosity, and to examine the effects of Joule heating. This research also aims to determine the effects of the other primary physical features of advanced thermal systems on the velocity, temperature, skin-friction coefficient, and Nusselt number.Design/methodology/approach Using boundary-layer approximations, a complete mathematical model is developed for the coupled hybrid nanofluid (which comprises four types of nanoparticles dispersed in two base fluids, i.e. blood and kerosene). The governing nonlinear partial differential equations are simplified to ordinary differential equations through similarity transformations. The resulting boundary-value problem is solved semi-analytically using the Homotopy Analysis Method (HAM), implemented in the BVPh 1.0 and BVPh 2.0 Mathematica solvers. A parametric analysis is performed on the stretching parameter, mixed convection parameter, magnetic parameter, nanoparticle volume fraction, and variable viscosity to analyse their effects.Findings Results show that increasing the mixed convection parameter significantly increases the fluid velocity and the heat transfer rate due to buoyancy-assisted flow. The magnetic parameter decreases velocity due to the Lorentz force, but increases temperature due to Joule heating. Greater nanoparticle volumes increase the Nusselt number and also increase the skin friction at the surface due to increased effective viscosity. The temperature-dependent viscosity influences the thickness of the boundary layer and the behaviour of thermal transport. The overall heat transfer of hybrid nanoparticles is much better than that of ordinary nanofluids.Originality/value Unlike other studies that considered single-particle nanofluids with constant rheological and thermal characteristics and simple linear stretching configurations, this work presents the first-ever coupled hybrid nanofluid model with four types of nanoparticles in two different base fluids as well as temperature-dependent viscosity and conductivity. The viscous and conductive effects of nonlinear stretching and shrinking surfaces, mixed convection, magnetohydrodynamic (MHD) forces, and Joule heating are coupled and solved using a semi-analytical homotopy analysis method-boundary value problem (HAM-BVP) approach. This type of simultaneous modelling offers a better understanding of and ability to predict the design of advanced thermal and MHD-type heat transfer systems.
Purpose This study proposes a new constitutive model to accurately capture the nonlinear, path-dependent strength degradation of high-performance concrete within an efficient computational framework.Design/methodology/approach An elastoplastic model is developed based on an extended Prandtl-Reuss formulation. A generalized invariant is introduced to decouple tension-compression asymmetry, while energy dissipation and non-elastic recovery are explicitly accounted for. Uniaxial stress-strain relations are derived to describe all through hardening-softening response. Model predictions are validated against multiple experimental datasets.Findings The model accurately captures the asymmetric hardening-softening response under monotonic loading and the path-dependent stiffness degradation during unloading, using only a limited set of physically interpretable parameters without introducing explicit damage or crack-tracking variables. Numerical comparisons confirm its predictive accuracy.Originality/value The formulation introduces a novel invariant for generalized tension-compression decoupling. Unloading stiffness degradation emerges intrinsically rather than from ad hoc assumptions. The model achieves physical clarity and computational efficiency, advancing simulation of concrete inelastic response.
Purpose This study seeks to examine and evaluate the seismic susceptibility of historic masonry structures in Annaba, situated in seismically active regions, employing nonlinear analysis with the 3Muri program. The study aims to discover effective strengthening measures while considering practical feasibility and the availability of local resources.Design/methodology/approach A multi-phase process was applied to a sample historic masonry structure in Annaba. The approach commenced with a comprehensive architectural and structural survey, encompassing precise geometric documentation of longitudinal and transverse sections, along with meticulous mapping of all observable fractures and structural deficiencies. A numerical model was constructed utilizing the 3Muri software, which applies the equivalent frame method for the nonlinear analysis of masonry structures, based on the gathered data. Nonlinear static (pushover) analyses were conducted to assess the seismic performance of the building in its current state. Multiple reinforcement scenarios, including CFRP reinforcement and a hybrid Steel Frame + CFRP solution, were simulated by altering mechanical properties to reflect retrofit interventions. Structural performance indicators and fragility curves were utilized to compare the behavior before and after retrofitting.Findings Analyses indicate a substantial deficiency in the seismic resilience of structures in Algeria, intensified by material degradation due to environmental exposure. Reinforcement and restoration are crucial, and our findings indicate that utilizing carbon fiber reinforced polymer (CFRP) strikes an optimal balance between efficiency and practicality, resulting in a reduction exceeding 50% in components vulnerable to severe damage, while markedly enhancing flexibility and resistance to collapse. The integration of a steel frame and CFRP yields the most significant enhancement in seismic performance, leading to the maximum decrease in possible damage at all performance levels.Originality/value This study investigates a viable method for seismic evaluation and preservation of brick heritage structures in Algeria. It incorporates comprehensive surveys, sophisticated numerical modeling, and fragility-based evaluation with restoration strategies according to the accessibility of local materials and the economic circumstances in Algeria. This study introduces one of the initial extensive implementations of the 3Muri program for the fortification of brick heritage structures with carbon fiber reinforced polymer (CFRP) within the Algerian environment.
Purpose This work's main goal is to evaluate the effectiveness and viability of using sand as an abrasive medium in abrasive water jet machining (AWJM) to cut laser-cladded stainless steel. To improve machining efficiency and surface quality, it seeks to determine the ideal process parameters that maximise material removal rate (MRR) while minimising surface roughness. To better understand the metallurgical reaction of cladded layers under high-pressure abrasive erosion, the study also investigates the microstructural changes that take place during AWJM.Design/methodology/approach In this work, the precision cutting of laser-cladded stainless steel utilising sand as the abrasive medium is investigated using AWJM. The impact of three important process parameters stand-off distance, abrasive flow rate and traverse speed was assessed using a Box-Behnken Design under response surface methodology (RSM). Surface roughness (Ra) and MRR were chosen as the performance responses. Additionally, to monitor microstructural alterations and evaluate metallurgical behaviour during machining, scanning electron microscopy (SEM) examination was carried out.Findings With a maximum MRR of 3.05 mm3/min and a minimum surface roughness of 2.08 & micro;m, the optimised AWJM parameters demonstrated a positive trade-off between productivity and surface finish. Under various machining settings, SEM examination showed unique surface features, linking finer textures with lower Ra and aggressive erosion with greater MRR. The work demonstrates the efficacy of the RSM-based optimisation strategy for hybrid material processing by confirming that sand abrasives are feasible for cutting cladded surfaces with high accuracy and little damage.Originality/value Using sand as an economical and environmentally friendly abrasive to machine laser-cladded substrates a combination that hasn't been extensively studied in the literature, this study offers a unique use of AWJM. A comprehensive assessment of process performance is provided by combining SEM for microstructural evaluation and RSM for parameter optimisation. The study advances hybrid machining techniques for complex, multi-layered materials in vital industrial areas by offering insightful information on striking the ideal balance between material removal and surface integrity.
Purpose Despite growing advances in reusable launch technologies, vertical takeoff and vertical landing (VTVL) rockets increasingly depend on accurate attitude transitions; nevertheless, the aerodynamic principles controlling stability and passive control effectiveness during crucial turnover maneuvers are still not fully understood. In particular, the nonlinear aerodynamic behavior and flow-structure interactions associated with curved-fin topologies during horizontal-to-vertical reorientation have received little theoretical attention, despite earlier research emphasizing trajectory optimization, guidance laws, and pose estimation. With a focus on lift, drag, pitching moments, and vortex-driven stability during turnover maneuvers, the current study seeks to close this gap by developing a rigorous, mechanistic, and theory-driven framework for nonlinear aerodynamic stability and passive control effectiveness in VTVL curved-fin rockets. Design/methodology/approach Geometric abstraction, quasi-steady aerodynamic modeling, flow-structure interaction principles, and systematic modifications of fin curvature and cant angle are combined in an integrated conceptual, analytical, and parametric approach. The formulation is based on a reduced-order aerodynamic modeling strategy, where coefficient-level response functions, including the lift coefficient, drag coefficient, and pitching moment coefficient, are used as primary descriptors of nonlinear aerodynamic behavior under turnover conditions. Under large-angle, transient flight conditions, the proposed framework enables predictive interpretation of nonlinear aero-fluid coupling mechanisms. Findings Curved fins generate nonlinear couplings through pressure redistribution, pitch-rate-dependent flow separation, and transient vortex formation, improving passive damping, stabilizing moments, and reducing overshoot during attitude transitions. Geometric and boundary effects govern intrinsic stability limits and passive control effectiveness. The observed nonlinear response trends are consistent with reduced-order aerodynamic signatures reported in the aerodynamic literature for high-angle-of-attack regimes. Originality/value Overall, the study presents a theory-grounded predictive framework that enhances understanding of aero-fluid interactions in VTVL rockets and provides design-relevant insights for improving turnover maneuver performance in future reusable launch systems.
Purpose Flexible electronic devices based on thin film/substrate structure are often subjected to thermal environments during operation. This study investigates the nonlinear dynamic response of a corrugated thin film/substrate structure under periodic thermal excitation to assess and ensure its reliability. This paper aims to explore the effects of excitation frequency, thermal amplitude, and pre-strain on the dynamic stability of the structure.Design/methodology/approach A nonlinear dynamic model considering thermal effects is established based on Euler-Bernoulli beam theory. The governing partial differential equations are discretized using the Galerkin method and solved numerically via the fourth-order Runge-Kutta method. Bifurcation analysis is conducted to determine the critical conditions triggering chaotic vibrations.Findings The dynamic stability of the thin film/substrate structure is primarily governed by the frequency and amplitude of thermal excitation. Elevated excitation frequencies cause the system to transition from periodic to chaotic vibrations, and pre-strain markedly modifies the stability boundaries. In addition, the influence of excitation amplitude on stability depends on the selected excitation frequency.Originality/value This study establishes a thermomechanical modeling framework for analyzing the nonlinear dynamic stability of corrugated thin film/substrate structures under periodic thermal loading. The findings provide essential insights for suppressing chaotic vibrations and offer practical guidance for the robust design of flexible electronics serving in dynamic thermal environments.
Purpose The purpose of this paper is to systematically investigate the influence of porosity, spatial distribution of pores and strain-rate sensitivity on the elastic–plastic and viscoplastic properties of pore-containing solids. Design/methodology/approach This work uses a finite element unit-cell approach to examine the mechanical response of three periodic closed-cell porous architectures: simple cubic (SC), body-centered cubic (BCC) and face-centered cubic (FCC). Rate-independent and rate-sensitive constitutive models are applied under uniaxial loading, to evaluate the overall stress–strain behavior, effective properties and internal deformation fields. Findings Numerical results demonstrate the fact that higher porosity results in lower effective Young’s modulus, Poisson’s ratio and plastic yield strength. An increase in loading rate for the viscoplastic solid leads to an enhancement of plastic flow strength. The existence of pores leads to a decrease in overall strain-rate sensitivity. This decreasing effect is more pronounced if the strain-rate sensitivity of the solid matrix is higher. The porous materials with a lower strain-rate sensitivity of the solid matrix exhibit more concentrated plasticity around the void, compared to the higher strain-rate sensitivity counterpart. Originality/value By consistently comparing SC, BCC and FCC closed-cell structures using a unit-cell finite element framework, the study clarifies the role of pore morphology and pore concentration in governing rate-dependent strength and plastic strain localization – an aspect rarely addressed in prior studies.
PurposeThis study is devoted to miniaturized creep testing for in situ performance assessment of high-temperature components. It seeks to systematically elucidate how the geometric parameters of flat mini-specimens-gauge-length ratio l/d, fillet-radius ratio R/d and thickness ratio t/d-influence stress concentration, creep deformation, life and damage evolution, and to establish a practically applicable recommended design window for specimen dimensions.Design/methodology/approachFlat mini-specimens were designed using l/d, R/d and t/d as non-dimensional geometric parameters. A three-dimensional finite element model incorporating the Kachanov-Rabotnov creep damage formulation was constructed to perform elastic and creep simulations. Mesh-convergence studies were used to determine the element type and local mesh refinement. On this basis, the stress concentration factor, creep life, core equivalent creep strain, displacements of the gauge section and gripping ends, and the time-dependent migration of the maximum-damage location were systematically evaluated.FindingsThe results show that the stress concentration factor is mainly governed by R/d, is only slightly sensitive to t/d, and is essentially insensitive to l/d. Stress, creep strain and damage are all concentrated in the central region of the gauge section, so the total displacement can be well approximated by the gauge-section displacement. When l/d = 2-3, the creep life approaches that of the reference specimen and the stress state is close to quasi-uniaxial, whereas at l/d = 1 the geometric effect becomes particularly pronounced. At l/d = 1, the location of maximum damage remains in the specimen core, while with increasing l/d the maximum-damage location migrates from the region near the fillet towards the core; this damage offset can be mitigated by increasing R/d and t/d.Originality/valueThis work establishes a dimensional assessment framework for miniaturized flat creep specimens by combining the K-R creep damage model with three-dimensional finite element analysis including the grips. The individual and coupled influences of l/d, R/d and t/d on creep behavior are quantitatively examined. A damage-migration metric based on the movement of the maximum-damage location is proposed, and dimension-design recommendations are provided that can be directly used for in situ extraction of high-temperature components and creep characterization with limited material volume.
Purpose This study aims to systematically investigate the effect of infill geometry on the mechanical performance and fracture morphology of polylactic acid (PLA)-based materials fabricated by fused deposition modeling (FDM). In particular, the relationship between infill pattern, material type, and microstructural fracture mechanisms is evaluated through combined mechanical testing and scanning electron microscopy (SEM) analysis. Design/methodology/approach Three different PLA-based filaments (pure PLA, PLA/Wood, and PLA/Cf) were printed using seven infill patterns at a constant infill density of 80% and fixed printing parameters. Standard test specimens were prepared according to ASTM D638, D695, and D790 for tensile, compressive, and flexural tests, respectively. A full factorial experimental design was employed, and each test was performed with three repetitions to ensure statistical reliability. SEM observations were conducted at multiple magnifications to examine interlayer bonding, void formation, and crack propagation behavior. Findings The results demonstrate that both material type and infill geometry play a dominant role in determining mechanical performance and fracture behavior. Among all configurations, the concentric infill pattern provided the highest mechanical strength for all materials. Pure PLA exhibited the best overall performance, while PLA/Cf showed fracture dominated by interfacial crack propagation. PLA/Wood samples exhibited high porosity, particle pull-out, and premature failure due to weak fiber–matrix adhesion. Originality/value This study offers a comprehensive evaluation of material-pattern interaction in FDM by integrating macroscopic mechanical testing with SEM-based fracture analysis. The results provide microstructural evidence explaining performance differences and establish a scientific framework for infill pattern optimization and material selection in performance-oriented applications.
Purpose The primary aim of this research is to comparatively evaluate three different pump types – vane pump, internal gear pump and helical gear pump – with different motor configurations in terms of energy efficiency, flow performance, and acoustic characteristics under varying rotational speeds. The study seeks to move beyond conventional pump selection criteria that focus mainly on hydraulic performance by incorporating energy consumption, noise levels, cavitation behavior and long-term operational considerations into the evaluation process. Another key objective is to identify the advantages and limitations of each pump type and to provide practical guidance for selecting the most suitable pump based on application-specific requirements, workplace comfort and cost optimization. Additionally, the study aims to highlight the importance of mitigating cavitation effects through appropriate engineering measures to improve pump lifespan and overall system efficiency. Design/methodology/approach The objectives are achieved through an experimental, comparative approach in which vane, internal gear and helical gear pumps are tested under varying rotational speeds. Key performance indicators – including flow rate, current consumption and noise levels – are systematically measured to evaluate energy efficiency, hydraulic behavior and acoustic performance. Cavitation effects are analyzed by correlating performance degradation and noise escalation at high speeds. The study adopts an engineering-based evaluation framework, focusing on pump selection and system design considerations. The scope of the article covers fluid machinery performance analysis, energy efficiency, acoustic behavior and practical implications for industrial pump applications. Findings The study found that pump performance is strongly influenced by the combined effects of rotational speed, cavitation, energy consumption and acoustic behavior. The vane pump provides the highest flow rates but suffers from significant performance degradation, high current draw and excessive noise at high speeds due to severe cavitation. The internal gear pump demonstrates a more balanced performance, with moderate flow rates and controlled increases in energy consumption and noise. The helical gear pump exhibits the lowest energy consumption and noise levels, showing minimal sensitivity to cavitation, although its flow capacity is comparatively limited. Originality/value This article provides a holistic and comparative evaluation of vane, internal gear and helical gear pumps by simultaneously considering hydraulic performance, energy efficiency, acoustic behavior and cavitation effects. Unlike conventional studies focusing mainly on flow performance, this work highlights the importance of long-term operational costs and workplace comfort in pump selection. The value of the article lies in offering practical, application-oriented guidance for engineers, designers and decision-makers involved in pump selection and system design, particularly in industrial applications where energy efficiency and noise reduction are critical considerations.
