Mihaela Oleksik

Friction in sheet metal forming processes is a key factor determining the material flow behavior and surface quality of products. Controlling friction conditions is crucial for ensuring the stability of the forming process. This article focuses on evaluating the influence of strip sample orientation, tool surface roughness, and contact forces on the coefficient of friction in the strip drawing test. Low-carbon, deep-drawing-quality steel sheets produced by rolling were used as the test material. Due to the complex influence of numerous parameters on the coefficient of friction, analysis of variance (ANOVA) was employed to evaluate the experimental results. A two-factor interaction model was used to analyze the data from the strip drawing test. An adequate precision of approximately 104.74 and coefficients of determination of R² = 0.9367, an adjusted R² = 0.9350, and a predicted R² = 0.9331 indicated that the regression model was sufficiently fitted to provide reliable predictions. It was found that the influence of sheet orientation on the coefficient of friction, under a varying load force, was minor; the difference in the CoF between the two sample orientations did not exceed about 0.01. On the other hand, among all the parameters of the strip drawing test, the load force was the decisive factor affecting the CoF. A trend was observed in which the coefficient of friction increased with a decreasing average roughness of the countersamples and load force.

The CoCrMo alloys are progressively utilized as biomaterials. This research is dedicated to studying the consequence of (1, 3, and 5) wt% nano-TiO₂ addition on the porosity, microstructure, microhardness, and wear behavior of pre-alloyed CoCrMo powder produced by powder metallurgy (PM). Microstructural features were examined using SEM, SEM mapping, and XRD. Wear behavior was assessed through pin-on-disk tests performed under dry sliding conditions at varying loads and durations. Porosity increased with the addition of nano-TiO₂, from 15.26 at 0 wt% reaching 25.12% at 5 wt%, while density decreased from 7.16 to 6.33 g/cm³. Microhardness exhibited a slight improvement, attaining 348 HV at 5 wt%. SEM and XRD analyses confirmed partial particle separation after sintering and identified the TiO₂ reinforcement as rutile. Wear tests revealed that adding 1 wt% nano-TiO₂ enhanced wear resistance, whereas extended sliding durations resulted in increased wear rates. Adhesive wear was the predominant mechanism, accompanied by limited abrasive wear, oxidation, and plastic deformation.

The paper presents the development of an axisymmetric numerical model for simulating the crimping process of pneumatic suspension components and the implementation of a Python script integrated into the Abaqus/CAE environment. Automation through the Abaqus Scripting Interface (ASI) significantly reduces preprocessing time and eliminates repetitive manual operations. The axisymmetric model describes the deformable behavior of metallic and elastomeric components, using CAX4R and CAX4H elements to ensure numerical stability and result accuracy. The script automatically generates geometry, material properties, contact definitions, boundary conditions, and analysis steps based on data provided in a parameterized Excel file. The proposed solution ensures consistency between simulations, allows rapid execution of parametric studies, and facilitates integration into industrial design workflows. The results demonstrate the efficiency of Python scripting in automating FEA-based analyses for complex industrial applications.

The aim of this paper is to identify the most suitable material model for the numerical simulation of the incremental forming of polymeric materials using the finite element method. The analysis program used was Ls-Dyna, and two material models, namely material 24 (Piecewise Linear Plasticity) and material 89 (Plasticity Polymer), were chosen for comparison from the library of the program. A comparison was made between two polymeric materials, polyamide PA 6.6 and polyethylene HDPE 1000, with the following dimensions of the forming tools: punch diameter, D_p = 6 mm; die length, L_d = 190 mm; die radius, R_d = 5 mm; die corner radius, R_corner = 10 mm; and blankholder length, L_bl = 190 mm. The simulation using the finite element method was performed with the Ls-Dyna software, and the experimental research was carried out using the Kuka KR210-2 robot. The strains were measured with the Aramis 2M optical system. Experimental investigations were carried out simultaneously, and the results obtained were compared in terms of main strains, thickness reduction, and forces on three directions. Close results were obtained between theoretical and experimental research for both material models.

The paper’s aim is to describe the stages of the experimental research as well as the processing of data measured in the SPIF of some polymeric materials using methods such as the Taguchi method, ANOVA analysis, and establishing the regression equation to determine the relevant factors of influence.

This article explores the process of calibrating the properties of DC01 materials for finite element analysis using ABAQUS and Isight. Precise calibration of yield strength and tensile strength is crucial for accurately modeling material behavior under various loading conditions. The article details the sample preparation process, deformation measurements, and tensile tests to obtain experimental data. These data are then used to calibrate the DC01 material model in ABAQUS with the assistance of Isight, ensuring that the simulations accurately reflect real-world behavior. The results indicate the success of the calibration, facilitating the design and testing of products in a predictive virtual environment. Precise calibration is essential for predicting material behavior in real-world conditions and minimizing the risk of implementation failures.

Using aluminium metal matrix nanocomposites has recently gained increased attention in the industry due to their high strength and ductility. In this paper, TiO₂ nanoparticles in volume percentages of 5 wt. % were added to the AA2024 alloy using the stir casting method. Using a novel powder injection system, TiO₂ nanoparticles with an average particle size of 30 ± 5 nm was added to the matrix. The influence of TiO₂ content on the fatigue life before and after heat treatment was studied. The results showed the fatigue properties of AA2024 with TiO₂ nanoparticles increased after heat treatment. The optimum improvement in fatigue properties was obtained at 5 wt. % TiO₂ after heat treatment, with an improving fatigue life in 14.71% compared with sample based. This is due to an increased number of fine precipitates besides its uniformly distributed after heat treatment. The fatigue life of the composite materials with added nanoparticles was investigated using a finite element-based ANSYS workbench. There was a good match between what happened in the experiments and what happened to the numerical fatigue strength. For the composite materials, the difference between the experimental and numerical values of fatigue strength was not greater than 4% for the matrix. The results also, indicated that, after ageing, the precipitate-free zone at the inter-dendritic zone disappeared or became smaller. However, after adding 5 wt. % of titanium and, also, performing heat treatment, it is not possible to precipitate the Al₂CuMg precipitates, and, instead of it, the Al₃TiCu and Al₇TiCu phases precipitates have been formed.

Polymeric materials are increasingly used in the automotive industry, aeronautics, medical device industry, etc. due to their advantage of providing good mechanical strength at low weight. The incremental forming process for polymeric materials is gaining increasing importance because of the advantages it offers: relatively complex parts can be produced at minimum cost without the need for complex and expensive dies. Knowing the main strains and especially the thickness reduction is particularly important as it directly contributes to the mechanical strength of the processed parts, including in operation. For the design of experiments, the Taguchi method was chosen, with an L₁₈ orthogonal array obtained by varying the material on two levels (polyamide and polyethylene) and the other three parameters on three levels: punch diameter (6 mm, 8 mm and 10 mm), wall angle (50°, 55° and 60°) and step down (0.5 mm, 0.75 mm and 1 mm). The output parameters were strain in the x direction, strain in the y direction, major strain, minor strain, shear angle and thickness reduction. Two analyses were conducted: signal-to-noise ratio analysis with the smaller-is-better condition and analysis of variance. The optimum values for which the thickness was reduced were the following: wall angle of 50°, punch diameter of 10 mm and step down of 0.75 mm.

Opening wedge high tibial osteotomy (OWHTO) is a surgical procedure often used to eliminate the effects of knee osteoarthritis, a disease that is becoming more widespread worldwide. Optimizing the geometric planning of this operation is a very important preparatory step for the success of the intervention and rapid postoperative recovery. This optimization is performed in two main directions. The first direction evaluates the intraoperative behavior of the tibia during the osteotomy by optimizing four geometric parameters that characterize geometric planning. The second direction aims at a postoperative evaluation of the flat tibia-osteosynthesis assembly taking into account the optimal position on the medial–lateral articular line through which the corrected mechanical axis of the tongue passes and implicitly offloads the transfer from the medial area to the side of the knee. The research methods used are exclusively computer-assisted such as: computer-aided design (hereinafter CAD) for geometric modeling of the tibia taking into account the real bone structure, the finite element method (hereinafter FEM) for performing numerical analyses and design of the experiment (hereinafter DOE) for the design of the research. The results obtained are eloquent and clearly presented and can be important elements for orthopedic doctors at the geometric planning stage of the OWHTO.

The realization of products from materials with high properties generally involves very high energy consumption. Thus, in the research, it was considered to optimize the machining process by cutting of an aluminum bronze alloy, so as to obtain a reduction in energy consumption in correlation with the roughness of the machined surfaces. The research focused on the processing of a semi-finished product with a diameter of Ø = 20 mm made of aluminum bronze (C62300). In addition, in the research, the aim was to establish some correlations between the amount of power consumed and the quality of the surfaces processed by cutting. In this sense, the forces were measured in the 3 directions specific to the cutting process (F_c; F_f; F_p) for 3 tools construction variants and power consumed. The results showed that, if a certain constructive variant of the cutting tool is used in the processing, a reduction of the power consumed to cutting can be obtained by approximately 30% and a reduction of the roughness of the processed surface by approximately 90–100%. Furthermore, following the statistical processing of the results, it was shown that it would be advisable to use, especially in roughing processes, the cutting tool variant that offers the greatest reduction in roughness and cutting power.