Friction drilling is a non-conventional technique that utilizes the heat generated by a rotating tool to penetrate material, simultaneously forming a bushing around the hole. In this study, the influence of key process parameters like spindle speed, feed rate, and material thickness on multiple output responses, including thrust force, torque, bush length, cylindricity, top diameter, and temperature, was systematically investigated using Taguchi optimization technique and analysis of variance (ANOVA). The results revealed that spindle speed was the most influential factor for thermal and force-related responses, particularly temperature and thrust force, where increasing speed from 2000 rpm to 5000 rpm reduced thrust force by nearly 22
Plasma transferred arc (PTA) surfacing with axial powder feed is an effective method for restoring and strengthening components made of stainless steels, particularly 12Х18Н10Т (AISI 321), which is widely used in mechanical engineering, power generation, aerospace, and rocketry. This paper presents a developed and tested universal modular device for generating an externally controlled volumetric magnetic field. The device comprises three magnetic cores with electric coils, inclined at an angle of 30–40° to the electrode axis and at 120° to each other, ensuring the formation of a controlled volumetric magnetic field in the plasma arc zone. Experimental investigations have confirmed the positive influence of the proposed device on the structure of the deposited layer. A comparison with plasma spraying based on published data is also discussed.
Abstract Rubber materials are widely used in the automotive industry due to their shock-absorbing properties, which are also utilized in steering systems to avoid high-rate compression loads at end-of-travel positions. This study presents a finite element analysis of a steel-rubber automotive endstop damper, with particular attention to the material properties of the rubber, the contact surfaces, and the tilting effect resulting from tolerances. During the study, three rubber grades (NBR80, NBR85 and HNBR80) were compared, using the Yeoh hyperelastic model combined with the Prony series-based linear viscoelastic model to capture mechanical behavior. During the nonlinear finite element analysis, the force-displacement characteristics, strain distribution, and energies were determined. Mesh and friction sensitivity analyses were also performed to evaluate the influence of the numerical settings. The numerical force-displacement responses were compared with the first experimental loading branches of the investigated NBR80 Ø42 configurations, with and without tilting, up to 31 kN. The individual loading curves showed reasonable agreement, while the tilting-induced displacement difference was not quantitatively validated. Within the investigated loading conditions, the model can be used for comparing the investigated steering system endstop damper design variants, reducing the need for physical prototypes.
Laser Powder Bed Fusion (LPBF) is one of the most important additive manufacturing (AM) processes for producing high performance and complex metallic elementary parts in critical industries such as aerospace and medical. The guarantee of machine readiness before production in terms of performance is crucial to meet the high quality requirements. However, many existing validation approaches rely on artifacts, destructive tests, or resource intensive characterization workflows. These operational constraints make them unsuitable for daily industrial use. Particular focus is given to the practical challenges faced by manufacturers when implementing these approaches in real production conditions. This study analyzes the existing approaches, evaluating their methodologies, strengths and limits in terms of speed, cost and suitability for industrial production Go/No Go decisions. The review highlights a critical gap in standardized, rapid and non-costly validation methods that can faithfully provide an assessment of the machine’s performance while ensuring part quality. This indicates an urgent need for standardized, pragmatic and industrially deployable validation approaches suitable for routine machine readiness assessment in LPBF serial production environments.
This study investigates the role of Maxwell nanofluids in enhancing thermal transport in fluid flow systems using semi-analytical approach. Conventional working fluids often exhibit weak thermal conductivity and limit the performance of heat transfer. Replacing these fluids with nanoparticle suspensions improves heat transfer capability and overall system efficiency. Various types of nanoparticles were utilized due to their high thermal exchange efficiency. Equations for momentum, continuity, concentration, and energy movement were integrated into the flow model as PDEs. By utilizing functional similarities, the constructed model was transmuted into the form of ODEs. The results of velocity, heat transfer, and concentration distributions were determined using numerical and semi-analytical simulations with Akbari-Ganji’s Method (AGM) and Finite Element Method (FEM). An evaluation was also conducted on the influences of various parameters such as Hartman, Nusselt number, buoyancy, an external heat source, chemical processes. The inclusion of nanoparticles boosts thermal transmission. Furthermore, an escalation in buoyancy parameter and the Hartman number variables leads to higher skin friction. Also, higher Maxwell relaxation parameters promote greater velocity and simultaneously suppress temperature distributions.
