Volume 67, Issue 6

In this study, the effect of flush grinding process on the corrosion fatigue behavior of step heat treated 7020 aluminum alloys was investigated. Corrosive fatigue tests were performed with a plane bending device in an atmospheric environment and in a corrosive environment provided by fresh sea water brought from the Black Sea. While performing fatigue tests, the stress ratio was taken as R  = 0. In the experimental study, it was observed that the fatigue strength of both the two-step aged samples and the two-step aged + flush grinding treated samples in the atmospheric environment was better than in the corrosion environment. It was observed that the flush grinding process had no improving effect on the corrosion fatigue properties of the samples subjected to the two-step aging.

The corrugated core sandwich structure consists of a corrugated sheet between two thin face sheets. Due to their high stiffness-to-mass ratio, metal sandwich panels in corrugated structures are an attractive industrial solution as structural components. Corrugated sandwich panels are often preferred in many applications since they are easy to manufacture process and low cost. The bending characteristics of aluminum corrugated sandwich panels with cores of various shapes subjected to three-point bending are investigated numerically in this paper. The core shapes are square, Y-form, trapezoid, diamond, triangle, sinusoid, hexagon, and symmetric Y-form. According to the numerical results, the symmetric y-form model showed optimum values for specific load-carrying capacity (SLCC) and specific energy absorption capacity (SEAC). The model that gives the optimum values by revising the symmetric y-form model has been determined. The revised model’s specific load-carrying capacity (SLCC) increased from 101.31 N·gr −1 to 106.89 N·gr −1 . The specific energy absorption capacity (SEAC) increased from 3.14 J·gr −1 to 3.71 J·gr −1 . It has been observed that the reduction of the section moment of inertia is also an essential factor in the collapse behavior of sandwich structures.

Plate auxetic structures, distinguished by their negative Poisson’s ratio, demonstrate unconventional mechanical responses, expanding laterally under tension and contracting under compression. These systems, particularly plate-based designs, are increasingly studied for their exceptional energy absorption, impact resilience, and structural versatility. This research investigates the mechanical behavior of nine auxetic geometries, including reentrant, chiral, antichiral, meta-chiral, arrowhead, star, and a new hybrid auxetic design for three different materials, which are 30 % short glass fiber reinforced polypropylene (GF30PP), polyamide 6 reinforced with 30 % of short glass fiber (PA6/GF30), and high-temperature resistant polyamide with 15 % carbon fiber (CF15) are materials of the auxetic structures used in this paper. Energy absorption performance, maximum forces, and specific energy absorption amount are analyzed to evaluate their suitability for the nine auxetic designs. Findings reveal that Design 9, which is developed in this paper, shows the best energy absorption capacity for PA6/GF30 and CF15 materials.

During vacuum hot pressing sintering process, the Al 2 O 3 generated in situ and Al 2 O 3 /Al composite are obtained. The ball milling and high – pressure torsion is used to improved tensile properties of Al 2 O 3 /Al composite. The effects of high – pressure torsion on the distribution of Al 2 O 3 and mechanical properties of the Al 2 O 3 /Al composite are discussed. The results show that under high – pressure torsion deformation, Al 2 O 3 films coated on the surface of Al powders are broken. The Al – Al interface is formed due to the broken Al 2 O 3 . Increasing the shear deformation degree is beneficial to the consolidation of Al powders and improves the hardness of the Al 2 O 3 /Al composite. The improved ultimate tensile strength of the Al 2 O 3 /Al composite benefits from the closure of voids and the formed Al – Al interface during high – pressure torsion deformation. After high – pressure torsion, the ultimate tensile strength and hardness of the Al 2 O 3 /Al composite with the ball milled Al powders are 198 MPa and 75.2 HV, respectively.

The galvanized advanced high strength steel (AHSS) with high manganese content tends to suffer the liquid metal embrittlement (LME) during the resistance spot welding (RSW) process. In this study, the LME susceptibility of one kind of galvanized AHSS with high manganese content was systematically evaluated based on the criterion of Auto/Steel Partnership (A/SP). The galvanized AHSS with high manganese content was welded at 16 groups of different welding currents from 7.0 kA to 14.5 kA with intervals of 0.5 kA. No evident LME cracks could be observed in the cross sections of those specimens below expulsion. However, numerous severe LME cracks could be clearly observed for the joints at or above expulsion. It was considered that the increase of the welding current aggravated the LME severity of this kind of steel. Additionally, the nugget size could be measured after the chemical etching. The nugget size gradually increased with increasing the welding current. Based on the A/SP criterion, the results revealed that this kind of galvanized AHSS with high manganese content exhibited high LME susceptibility, thus not meeting the requirements. Except for the large welding current, it was deemed that the high Mn content was the crucial factor to lead to high LME susceptibility of this steel.

In this study on low temperature aluminized Monel 400 alloy, the growth kinetics of the aluminide layer are reported. Ni-based super alloy samples were aluminized for 2, 4, and 6 h at 600, 650, 700, and 750 °C, respectively. The morphologies and types of aluminides that developed on the Monel 400 substrate surface were examined using energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), and X-ray diffraction analysis (XRD). The thickness of the boride layer varied between 4 and 40 μm. The temperature and duration time of treatment had an impact on the hardness of the aluminides that developed on the samples, ranging from 800 to 250 HV. By altering the treatment’s temperature and duration, the reaction’s kinetics were also determined. A regression model was utilized to create an equation that can estimate the thickness of the aluminized layer based on the parameters of time and temperature. The projected values of the thickness of the aluminized layers were compared to the corresponding measurements obtained through experimentation, and a satisfactory agreement was achieved. Furthermore, a contour diagram is a recommended tool for determining the appropriate thicknesses of aluminized layers based on the prospective industrial applications of Monel 400.

This paper mainly studies the welding of annular fillet weld using carbon dioxide gas shielded welding and interrupted pulsed arc welding (IPAW) method, using ABAQUS finite element technology to simulate the in-service welding process of X80 pipeline, and comparatively analyze the carbon dioxide gas shielded welding and IPAW of the priming layer, the overall weld temperature field and the distribution of stress field. The distribution patterns of the priming layer, overall welding temperature field and stress field of carbon dioxide gas shielded welding and IPAW were comparatively analyzed. The results indicate that, in addition to the conventional carbon dioxide gas shielded welding method, improved pulse arc welding (IPAW) is also suitable for welding repair. IPAW can significantly mitigate the adverse effects on the base material during welding. It demonstrates superior performance in controlling thermal effects and stress concentration within the weld zone, resulting in a smaller heat-affected zone compared to that produced by carbon dioxide gas shielded welding, thereby effectively reducing overall residual stress. Through finite element simulation, it is possible to replicate in-service welding conditions, optimize welding process parameters, control heat input, monitor welding residual stress, and provide data-driven support for actual repair welding, ultimately enhancing repair quality.

In this study, biomechanical evaluation was performed to select appropriate dental implant material, and the implant-bone model was verified by finite element analysis (FEA). Ti–6Al–4V, ZK60, WE43, HA, and Ta materials were compared using three different multi-criteria decision-making (MCDM) methods according to lightness, functional durability, relative movement, penetration, and cost criteria. The stress, deformation, safety factor, sliding distance, and penetration distributions obtained under four loading conditions were scored according to these evaluation criteria and Ti–6Al–4V was determined as the most successful material. By adding 0.1 mm wide and deep micro-grooves to the dental implant model, an 8.3 % improvement in sliding distance and a 53 % improvement in penetration were achieved.

This study examines the mechanical performance of novel PLA/PCL intervertebral cage designs for lumbar spinal fusion, using FEA and experimental compression testing. Four 3D-printed cage designs with varying graft window sizes and structural volumes were tested for load-bearing capacity. Experimental compressive strengths ranged from 43.36 MPa for Cage 4–50.43 MPa for Cage 3, all meeting the mechanical requirements of spinal applications. Cage 2, with a dual-window design, exhibited optimal load distribution and the highest compressive strength (50.00 MPa), indicating enhanced stability. Conversely, Cage 4, prioritizing graft space with the largest window, demonstrated the lowest compressive strength, revealing a trade-off between graft window size and structural support. FEA findings aligned well with experimental results, showing consistent trends in load distribution. Cage 2 exhibited the lowest von Mises stress, while Cage 4 had the highest stress concentrations, indicating vulnerability to deformation. This consistency between FEA and experimental data validates the reliability of FEA in evaluating cage designs. The findings suggest that PLA/PCL cages are viable alternatives to conventional materials, advancing the development of sustainable, patient-specific spinal fusion solutions. This study emphasizes the critical role of design in achieving a balance between structural support and potential for effective graft support in spinal implants.

Friction stir processing (FSP) is a well-known method for improving metal alloys’ surfaces by producing surface composites with better mechanical properties. This study examines how the tool tilt angle affects the FSP region generation in an AZ31 magnesium (Mg) alloy reinforced with yttria-stabilized zirconia (YSZ) and alumina (Al 2 O 3 ). The effect of different tool tilt angles (T TA ) on the dispersion, integration, and distribution of YSZ and Al 2 O 3 in the Mg matrix was investigated. Optical microscopy, scanning electron microscopy (SEM), and Vickers hardness testing were used to extensively evaluate the microstructural and mechanical characteristics of the FSP-treated region. The findings show that the T TA has a major impact on the surface composite’s homogeneity and uniformity, with 2° T TA encouraging the best possible dispersion of YSZ/Al 2 O 3 and enhanced mechanical properties. T TA of 2° friction stirred surface hybrid composite (FSSHC) exhibits a greater hardness of 137 HV as compared to the FSP-treated (106 HV) and the base alloy (73 HV). This is due to the Orowan strengthening mechanism and also because FSSHC has the ability to withstand a load through the inclusion of YSZ/Al 2 O 3 particles, and the homogeneous distribution of YSZ/Al 2 O 3 particles among the recrystallized base alloy grains provides homogeneous reinforcement across the stirred region.

In this study, NiCrCo and NiCrCo + XCr3C2 powder were added to surface of the AISI 304 stainless steel at certain rates and the steel surface was coated by TIG welding. As a result of the coatings, no cracks, voids or rupture were observed between the substrate and the coating layer. Optical microscope (OM), scanning electron microscope (SEM), X-ray diffraction (XRD), and energy dispersive spectrometry (EDS) tests were performed on the samples to examine the microstructure of the coating surface. Besides these analyses, wear and microhardness tests were also performed. NiCrCo + 10 wt.% Cr3C2 reinforced coating sample showed the best wear resistance. The highest hardness value of 357.5 HV was obtained in the NiCrCo + 15 wt.% Cr3C2 reinforced sample.

This study investigates the importance of material selection and the material index in FGM beam stress analysis. The stress distribution in functionally graded beams (FGMBs) using, FEA, numerical methods are investigated. Three different material distribution functions are examined, power law, modified symmetric power law, and sigmoid. The maximum equivalent and shear stresses occurs for each function and at different values of the material index (k) are considered. Overall, the study emphasizes the importance of material distribution function selection and material index values in determining the stress distribution and behavior of FGM beams. The study uses ANSYS 2020 for numerical analysis. The material properties of aluminum and alumina are used for the FGM beam. The results indicate that power law functions has a higher stress compared to modified symmetric power law. The best formula can be used in making FGM is modified symmetric power law as it produce minimum equivalent and shear stresses in comparison with the other formulas. The value of the material index (k) significantly affects the magnitude of both shear and equivalent stress for power law, modified symmetric power law only. The value of the material index (k) significantly influences the magnitude of both shear and equivalent stress.

AA8011 aluminum-based metal matrix composite is fabricated with ceramic-reinforced particles such as titanium dioxide and aluminum silicate. The weight percentage of titanium oxide was varied from 0 to 15 with an increment of 3 wt.%. The other reinforcement element, aluminum silicate, was kept constant at 6 wt.%. The metal matrix composite was fabricated using the stir casting process. From the experimental results, the hybrid composite fabricated with 6 wt.% aluminum silicate and 9 % titanium oxide exhibited a higher strength of 132 MPa. The strength of the hybrid composite increased as the weight percentage of reinforcement particles increased from 3 to 9 wt.%. The porosity and density of the hybrid metal matrix increased while increasing the weight percentage of reinforcement from 3 to 15 wt.%. The maximum hardness of 97VHN was observed at the maximum percentage of reinforcement. This may be attributed to the addition of reinforcement in AA8011 aluminum alloy. A low wear rate of 4.72 × 10 −7 was recorded with 6 wt.% aluminum silicate and 15 wt.% titanium oxide. The reason for the lower wear rate may be attributed to the uniform distribution of reinforcement particles in the matrix.

In the era of artificial intelligence (AI), optimization and parametric studies of engineering and structural systems have become feasible tasks. AI and ML (machine learning) offer advantages over classical optimization techniques, which often face challenges such as slower convergence, difficulty handling multiobjective functions, and high computational time. Modern AI and ML techniques may not effectively address all critical design engineering problems despite these advancements. Nature-inspired algorithms based on physical phenomena in nature, human behavior, swarm intelligence, and evolutionary principles present a viable alternative for multidisciplinary design optimization challenges. This article explores the optimization of various engineering problems using a newly developed modified hiking optimization algorithm (HOA). The algorithm is inspired by human hiking techniques, such as hill climbing and hiker speed. The advantages of the modified HOA are compared with those of several famous algorithms from the literature, demonstrating superior results in terms of statistical measures.

This study investigates the interplay between process and computation parameters affecting the accuracy of finite element analysis (FEA) results for cup manufacturing. By revisiting the Esaform-2021 benchmark, this research aims to elucidate the impact of process parameters on FEA accuracy and recommend strategies for enhancing cup drawing fidelity. By conducting a parametric study focusing on the force–displacement behavior of a 6016-T4 alloy cup drawing process, an “optimized” force–displacement curve was obtained, demonstrating improved agreement with reference results. Die clearance, friction coefficient, time step size, and termination time are used in parametric finite element study. Key findings from the parametric study can be concluded that die clearance significantly affects punch force; a die clearance of 1.4 mm yielded the best match with experimental results, attributed to reduced blank-stuck phenomenon compared to smaller clearances. The friction coefficient showed a direct impact; a friction coefficient of μ  = 0.1 accurately replicated the experimental peak force, highlighting the sensitivity of force predictions to friction parameters. Time step size and termination time demonstrated minimal influence on FEA results, suggesting prioritization of parameters accelerating solution time. Finally, the relationships between process and FEA computation parameters and predictions were revealed for more realistic cup drawing process prediction accuracy.