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The importance of sintering is explained in this abstract, with a focus on how it helps achieve the precise fit, structural stability, and natural aesthetics that are necessary for dental restorations to be effective. A crucial method in the creation of dental prostheses, especially dental bridges, is the sintering process. Through a regulated heating procedure, dental ceramic particles are fused together to create a final product that is both visually beautiful and extremely durable. The ideal mechanical qualities, such as strength and biocompatibility, are ensured by the high-temperature amalgamation of ceramic particles. A dimensional examination of the collected dental samples can be carried out by the 3D scanning process, and a comparison with the 3D models that served as their foundation is made. The 3D scanner used in this research is the Atos Core 200, while the comparison with the 3D model was made in the GOM Inspect program (GOM Metrology GmbH, Braunschweig, Germany). Based on the measurements obtained by 3D scanning, the average deviations characteristic of individual technological processing procedures were obtained. This approach enabled more precise model-making and savings on materials.

The precision of 3D printing in the fabrication of sintered dental metalwork is critical for successful clinical outcomes. However, during the initial trial of these metal components on the patient, a dimensional discrepancy often manifests itself, indicating a poor fit despite being modeled from precise intraoral scans. This necessitates additional corrections or reprinting, thus extending the duration of treatment, increasing costs, and raising concerns about the reliability of 3D printing and subsequent processing techniques. This study aims to quantitatively analyze the dimensional changes in sintered dental metalwork from the original intraoral scan to the final product and to evaluate whether these changes are influenced by the complexity of the metalwork design. Using a 3D scanner (Atos Core 200, GOM, Germany), the dimensions of the sintered metalwork were compared to the corresponding CAD models. Preliminary results indicate significant dimensional deviations, particularly in more complex designs, underscoring the need for improved accuracy in the 3D printing process to enhance clinical outcomes and efficiency.

The Optical methods can be highly useful for analysing Pipe Ring Tensile Specimens (PRTS) since they offer an accurate and non-destructive method of evaluation. Optical technologies have several uses, such as Digital Image Correlation method (DIC method), thermal imaging camera, and 3D scanning. The DIC method is used to measure stresses and full-field displacements. DIC analyses a speckle pattern that is applied to the surface of the specimen and can provide detailed information on strain distribution, deformation gradients, and likely failure spots. An infrared thermal imaging camera can be used to detect defects in pipe specimens, such as fractures or delamination, by tracking the distribution of surface temperatures. Temperature anomalies can indicate areas of intense stress or material degradation. A 3D scanner is a device that uses the shape, size, and texture of physical objects to digitise them into three-dimensional digital representations. The investigation focused on five distinct PLA PRTS. The study describes how to evaluate PLA PRTS using DIC method, thermal imaging camera, and a 3D scanner. The evolution of strain was monitored using the 3D Digital Image Correlation approach. Using a thermal imaging camera, the temperature field change in the PRTS was investigated during the test. In order to verify the cross-sectional shape of the PRTS after a fracture, 3D scanning was performed on each specimen.

The integration of 3D printing technology into orthopedic practice addresses the critical problem of enhancing surgical precision and improving patient-specific treatment. Traditional orthopedic methods often involve generic implants and extensive preoperative planning, which can lead to suboptimal fit, prolonged surgery times, and varied patient outcomes. To solve this problem, patient-specific 3D anatomical models and custom implants can be used. High-resolution imaging data from patients can be converted into 3D-printed models, allowing for detailed preoperative planning and the creation of implants tailored to individual anatomical structures. This method also uses biocompatible materials and advanced printing techniques to ensure structural integrity and functionality. The use of 3D-printed models facilitated an enhanced preoperative understanding of complex anatomies, leading to reduced operative times and increased surgical precision. Customized implants result in better fit and integration with the patient's body, contributing to faster recovery times and higher patient satisfaction. Case studies indicate that this approach minimizes complications and optimizes overall orthopedic care. Despite promising results, challenges such as regulatory limitations, cost considerations, and the need for interdisciplinary collaboration remain. However, ongoing research and technological developments are expected to further refine these applications, paving the way for greater adoption and more widespread benefits in orthopedic practice.

Fracture mechanics, a fundamental field in materials science and engineering, deals with the study of crack initiation, propagation, and fracture resistance of materials. Traditional methods in fracture mechanics analysis often rely on analytical or numerical approaches, which may have limitations in capturing crack behavior under various loading conditions. To overcome these challenges, the 2D Digital Image Correlation (2D-DIC) method, a noncontact, full-field measurement technique, is employed to precisely quantify displacement and strain values. This paper investigates the application of the 2D-DIC method in the field of fracture mechanics. Through an experimental investigation that involves fracture toughness testing, crack growth monitoring, and fatigue crack propagation analyses, the effectiveness of 2D-DIC in capturing crack behavior is demonstrated. The results showcase the method's ability to accurately track crack propagation, providing valuable insight into crack growth mechanisms, and offering new data for understanding fracture mechanics phenomena. This paper contributes to advancing the field by highlighting the utility of 2D-DIC as a powerful tool for studying crack behavior and improving the overall understanding of fracture mechanics.

The three-point bending test is a valuable method for evaluating the mechanical properties of 3D-printed biomaterials, which can be used in various applications. The use of 3D printing in specimen preparation enables precise control over material composition and microstructure, facilitating the investigation of different printing parameters and advanced materials. The traditional approach to analyzing the mechanical properties of a material using a three-point bending test has the disadvantage that it provides only global information about the material’s behavior. This means that it does not provide detailed insight into the local strain distribution within the material. However, the 2D Digital Image Correlation (DIC) method offers additional insight, especially in terms of strain localization. DIC is an optical technique that measures full-field displacements and strains on the surface of a sample. PLA and enhanced PLA-X material were utilized to create three-point bending samples. The aim of this paper was to analyze and compare the influence of aging on the mechanical properties of PLA and enhanced PLA-X materials using three-point bending coupled with the DIC method. The results showed statistically significant differences between the PLA and PLA-X, for both the new and aged materials. The aged PLA samples had the highest average value of maximal force around 68 N, which was an increase of 8.8% compared to the new PLA samples. On the other hand, the aged PLA-X material had an increase of 7.7% in the average maximal force compared to the new PLA-X samples. When comparing the two materials, the PLA samples had higher maximal force values, 6.2% for the new samples, and 7.3% for the aged samples. The DIC results showed that both the new PLA and PLA-X samples endured higher strain values at Points 1 and 2 than the aged ones, except for the aged PLA-X sample at Point 2, where the new sample had higher strain values. However, for the first 5 min of the experiment, both

Today, the waste material obtained by 3D printing operations presents significant challenges due to the increasing global adoption of this technology, leading to serious environmental implications. The generation of plastic waste from unsuccessful prints and end-of-life products is a growing concern, impacting the circular economy. With a 26% annual growth rate in additive manufacturing, the amount of waste is rapidly increasing, necessitating effective waste management strategies. However, 3D printing offers advantages in waste reduction compared to traditional manufacturing methods, with only 40% waste generation compared to subtractive technologies and much of the waste being recyclable. The challenges of waste material obtained by 3D printing are numerous and require a comprehensive approach to waste management and recycling. Moreover, leveraging the abundant opportunities for reusing materials and developing sustainable composite filaments, 3D printing can contribute to environmental sustainability and the principles of circular economy.

Eco-art and recycling initiatives often involve comprehensive community engagement and participation in specific conditions. This paper explores the synergy between eco-art and recycling processes, as an optimal strategy to advance environmental preservation, alongside the integration of land art with ecological concepts. As environmental concerns escalate, the integration of ecoartistic measures and practices with recycling initiatives emerges as a potential to enhance environmental consciousness and sustainability. The study delves into the interconnectedness of these two disciplines, examining how the creative expression of eco-art can amplify the impact of recycling efforts and activities, leading to heightened environmental awareness and conservation. By detailed examination of the intersections of these creative and ecological disciplines, the research aims to contribute insights into innovative approaches that simultaneously harmonize artistic expression and environmental conservation aspect, with the final important task of protecting our planet and ensuring sustainable development.

The pantograph’s purpose is to transfer electrical power from the overhead contact line to the train’s electric propulsion unit. To perform its function adequately, it is necessary to maintain the static contact force between the pantograph and the contact line within the values prescribed by appropriate standards for the entire extension range of the pantograph. The requirement to reach high contact lines complicates the kinematic scheme because the deviation of the trajectory of the pantograph’s collector head from vertical is also prescribed by standards. Further, the structural design of the pantograph is challenging because the greater slenderness ratio of the structure makes it difficult to meet the requirements in terms of stiffness and resistance to vibrations. While at low speeds aerodynamic forces are usually neglected, in high-speed pantographs, they have a significant impact and it is necessary to compensate for them. An aggravating circumstance is the requirement that the pantograph should work in both knuckle-downstream and knuckle-upstream directions. This paper aims to present the development of a high-speed high–reach pantograph that is developed through the cooperation of company Minel General Electric and the University of Belgrade – Faculty of Mechanical Engineering as well as to present innovative designs of gravitational and aerodynamical compensations that enabled the satisfaction of requested requirements in terms of geometric and static performance.

A global problem for industrial plants that contain process equipment operating under high pressure is the assessment of the integrity of the equipment, specifically the pipelines. Standard procedures for determining fracture mechanics parameters (ASTM E1820) for materials used in pressure piping construction cannot be applied to most thin-wall pressure components. One of the solutions to this problem is the introduction of new procedures and geometries of test specimens. In order to understand the nature of the behavior of the specimens and to determine the parameters whose critical values are important for integrity assessment of the pipeline under pressure, a detailed analysis of the model of the non-standard ring-shaped specimen is necessary. This paper will present the results of the analysis of fracture mechanics parameters obtained by the finite element method using the Simulia Abaqus software package. The properties of the material used in the software correspond to the properties of the P235TR1 pipeline material obtained by tensile testing on cylindrical samples with initial crack. The ratio of crack length (a) to sample width (W) corresponds to standard sample geometries and varies from a/W = 0.4 to a/W = 0.6. The values obtained from SENT (Single Edge Notched Tension) models with the same cross-section and a/W ratio were taken as reference values in relation to which the comparison is made. As a result of this research, the ratio of fracture mechanics parameters of the ring-shaped model (Pipe Ring Notched Tension – PRNT specimen) with a crack and the SENT model was obtained. The values of the J-integral were also obtained, distribution of values along the crack front does not correspond to the profile obtained on the SENT model. As a result of this test, a procedure for determining the critical value of the J-integral for models corresponding to the tested P235TR1 pipe samples was established, which is an important step in establishing a new procedure for

Conventional tensile testing is most commonly used for determining the basic mechanical properties of the material. However, this approach is challenging for in-depth analysis of material behaviour, especially related to heterogeneous materials. The Digital Image Correlation (DIC) method is a contactless optical method that overcomes the constraints of traditional experimental methods (e.g., strain gauge) and allows for full-field displacement and strain measurement. The paper specifically covers 2D-DIC application on tensile testing thin flat specimens prepared using cotton textile with 130 g/m2 density. Results show significant differences in von Mises strain values over the surface of the specimen, ranging from 8 to 24 %. The application of 2D-DIC in this case shows the significance of full-field analysis, as conventional usage of the tensile test would have missed the difference in mechanical properties of adjacent areas on the same specimen. 2D-DIC provides high spatial resolution, accuracy, real-time data acquisition, and visualization, making it a valuable tool for characterizing mechanical properties of thin flat specimens and understanding deformation mechanisms.

Additive manufacturing technologies have developed rapidly in recent decades, pushing the limits of known manufacturing processes. The need to study the properties of the different materials used for these processes comprehensively and in detail has become a primary goal in order to get the best out of the manufacturing itself. The widely used thermoplastic polymer material acrylonitrile butadiene styrene (ABS) was selected in the form of both filaments and ABS-like resins to investigate and compare the mechanical properties through a series of different tests. ABS-like resin material is commercially available, but it is not a sufficiently mechanically studied form of the material, which leads to the rather limited literature. Considering that ABS resin is a declared material that behaves like the ABS filament but in a different form, the objective of this study was to compare these two commercially available materials printed with three different 3D printers, namely Fused Deposition Modelling (FDM), Stereolithography (SLA) and Digital Light Processing (DLP). A total of 45 test specimens with geometries and test protocols conforming to the relevant standards were subjected to a series of tensile, three-point bending and compression tests to determine their mechanical properties. Characterization also included evaluation of morphology with 2D and 3D microscopy, dimensional accuracy of 3D scans, and Shore A hardness of each material and 3D printing process. Tensile testing results have shown that FDM toughness is 40% of the value for DLP. FDM elongation at break is 37% of DLP, while ultimate tensile stress for SLA is 27% higher than FDM value. Elastic modulus for FDM and SLA coincide. Flexure testing results indicate that value of DLP flexural modulus is 54% of the FDM value. SLA strain value is 59% of FDM, and DLP ultimate flexure stress is 77% of the value for FDM. Compression test results imply that FDM specimens absorb at least twice as much energy as vat polymeri

Different pipe manufacturing techniques, such as the manufacture of seamless pipes in the oil sector employing a conical shaft, necessitate data on the circumferential strain and stress condition of the pipe. The purpose of this study was to evaluating the displacement, strain, and stress behavior of a pipe ring tensile specimen (PRTS) in the hoop direction, as there was a lack of a standardized testing methodology. Five single S235JRH steel PRTS were tested for the study. The study describes how to test S235JRH steel PRTS with a Digital Image Correlation approach. The 3D Digital Image Correlation technique methodology was used to record the evolution of the strain. In the break zone and almost equivalent locations, all Single PRTS fractured. The experimental ultimate strength value's deviation value (also known as the real stress value) is greater than the theoretical ultimate strength value.

The three-point bending test is a widely used and important method for evaluating the mechanical properties of materials. Its versatility, applicability, and ability to provide valuable information on flexural strength, stiffness, and fracture toughness make it a valuable tool in materials science, engineering, and biomedical research. Digital Image Correlation (DIC) provides a high resolution and full-field measurement of deformation during the bending process. DIC also allows for the calculation of strain fields, which can be used to determine material properties such as Young's modulus and Poisson's ratio. This is particularly important in understanding the strain distribution and identifying potential failure mechanisms in the material. In this paper, the potential application of the 2D Digital Image Correlation method on three-point bending tests is presented.

In order to develop a non-standard method for determining the resistance to fracture and damage of pipeline materials, a new geometry of ring-shaped specimens with sharp notches or cracks has been defined. The need to develop a new method for testing of the specimens cut from the pipes arises due to the difficulties in determination of fracture mechanics parameters on thin-walled pressure pipelines, especially those with a smaller cross-section, by application of the standard procedures/specimens. Previous studies dealing with the topic of pipeline testing by non-standard methods are presented in the introductory part of the paper. In the experimental part of the research, tests on PRNT (Pipe Ring Notched Tension) and SENT (Single Edge Notched Tension) specimens are performed. Samples of these specimens were produced by SLS (Selective Laser Sintering) technique of additive production from PA12 (polyamide PA 2200) material. For the purpose of this study, a tool that is protected at the national level (in Serbia) as intellectual property is used for testing of the ring-shaped PRNT specimens. Tensile testing of both types of specimens is monitored by Aramis GOM 2M system; its operation is based on the method of digital image correlation, DIC. Additionally, finite element analyses are conducted on the PRNT and SENT geometries, enabling the calculation of the fracture mechanics parameter – Stress intensity factor K. It is concluded that the presented procedure based on the PRNT specimen has a good potential for use as a non-standard method for fracture resistance examination of pipeline materials. It can be performed on the specimens cut directly from the pipes (new or from exploitation). The dependence of the fracture resistance on the stress concentrator size is not pronounced, which means that the results depend dominantly on the material properties, rather than on geometry.