The main objective of this work is the numerical analysis of the strength and stiffness of an annular three-layer circular plate with variable mechanical properties of the core. The plates are subjected to bending. Numerical analysis of the deflection phenomenon is carried out under different support conditions of the plate. Furthermore, the influence of the material properties of the core (linear and non-linear model) on the shear stresses and deflecions is also investigated.
This article presents a process of developing a computational model of a light construction vertical lathe. The model is made using the finite elements method. Due to the complexity of the machine tool and the optimization of the computation time superelements have been used in the model. The application of this method has reduced the computation time allowing the analysis of many variants of the mutual position of the machine components. The results of the analyzes led to the indication of weak links of the machine tool. After the improvement of the machine tool construction the movement of the tool tip and the workpiece was much smaller.
Mohamed Serier, Mohamed Berrahou, Affaf Tabti and Seif-E Bendaoudi
The friction stir welding process is an innovative technique for joining metals using plasticity, without presenting the fusion. It was first applied to aluminum alloys, for example copper, steel alloys, polymers and others. In this work the effects of the rotational speed, the speed of travel and the axial force of the tool were grouped in a mathematical model to quantify their influences on the weld seam. In this context and with of the experimental tests, the desired objective through this study is to describe the tensile strength of the cord resulting from this welding operation, for the qualification of this type of parts with an optimum adapted to a given application.
The nanocomposites of polyamide 6 (PA6) with halloysite nanotubes (HNT) were prepared by extrusion using co-rotating twin-screw extruder and then the standard test specimens were injected using a screw injection moulding machine. The content of HNT in the nanocomposites was 5 or 10 weight percent. The heat treatment of unmodified PA6 and nanocomposites was carried out in silicone oil in temp. 150±2°C. The samples were annealed for 3 hours and then cooled at a rate of 4 K/min. Differential scanning calorimetry (DSC) causes annealing to increase the crystallinity of the polyamide matrix. After an annealing treatment a nanocomposite with better mechanical properties was obtained. Halloysite nanotubes in polyamide matrix play the role of a nucleating agent.
Wojciech Paszkowiak, Tomasz Bartkowiak and Marcin Pelic
This paper demonstrates kinematic analysis of multiple trailers on a tractor system for production logistics. The analysis concerned three different steering systems of the trailers: virtual clutch and drawbar system, conventional clutch and drawbar system, double Ackermann steering system. Designed kinematic models contain various variants of paths: turning at a constant value of the steering angle, changing the steering angle as a result of an approaching collision. Each of these variants also included driving in a straight line after a 90° turn. The validation of the developed kinematic model was done by using a real logistic train, which path was registered via aerial drone. For each of the developed kinematic models, a visualization of drive through the 90° turn was created.
Robert Koteras, Michał Wieczorowski, Piotr Znaniecki and Natalia Swojak
The subject of the article is an attempt to determine the impact of the applied measurement strategy on the accuracy of the measurement result. This problem is particularly crucial when measuring large objects. In these cases, it is not always possible to provide ideal conditions for the submission of particular scans. It is necessary to adjust the strategy to specific imposed conditions defined by the geometry of the object and to the time frame of the measurement itself.
With regard to the above, an attempt was made to carry out a series of accuracy studies testing the structural light scanner while measuring elements of overall dimensions greater than the measuring capacity of the scanner. At the same time, various potential measuring strategies were simulated in practical applications. Our studies were conducted using a pre-designed test template with a defined distribution pattern of reference points and geometrical elements. Moreover, in order to make an in-depth investigation of the issue, some trials were undertaken with the use of limiting parameters. That means the scanner had both an excess and shortage of information required for a correct assembly of scans. Those scopes were taken into consideration in the study in order to use the acquired knowledge in practical measuring applications. Furthermore, conclusions from the conducted studies indicate peaks and troughs of respective measuring strategies with special care for determining relationships among the used strategies and the measuring accuracy parameters.
The shape and type of chip give general information about the cutting process. This paper presents the results of testing the shape and type of chips of Ti6Al4V titanium alloy after it finishes turning. The process was carried out under dry, wet and MQL (Minimum Quantity Lubrication) conditions at variable cutting speeds and feed rates and a constant depth of cutting. For planning the tests, the PSI (Parameter Space Investigation) method was used, which allows the experiment to be carried out while minimizing the number of experience points. It was found that the cutting speed and feed affect the type and shape of the chip, and clear differences were observed between dry and wet cooling conditions, and MQL conditions. During turning, the intensity of the cutting speed and feed influence on the chip compression ratio was changed. It was similar for dry and wet cooling conditions but smaller for MQL conditions. The purpose of this research is to analyze the chip shaping when Ti6Al4V titanium alloy finishes turning under dry, wet and MQL cooling conditions.
After many years of intensive work the international experts from ISO TC 39 published the technical report called ISO TR 16907 “Machine tools – numerical compensation of geometric errors”. This document defines the terminology, presents benefits and limitations of numerical compensation of machine tools’ and measuring machines’ errors. It gives machines manufacturers and users vital information about how to use numerical compensation. In the context of those types of compensation defined in ISO TR 16907, this article shows rules of selecting models of Volumetric Error for three-axis machine tools. What is more, this paper presents some principles of reduction of these proposed models because of the functional tasks for machine tools. One of the obtained results is an array of reduced models for three-axis machine tools. This array determines the degree of detail of the model and the experimental research program that needs to be carried out in order to determine the Volumetric Error distribution.
The paper analyzes the process of internal honing of cylindrical gears, a new and modern method of finishing the gear tooth flanks. At the beginning, the kinematics of the process is being analyzed. By realizing the state of art, we were able to identify the main features of the process, its advantages in terms of surface precision and quality, the residual stresses and the wear of the flanks compared with other finishing processes. An experimental study of the geometric precision, the shape of the flanks and the roughness for honed surfaces compared to the unfinished ones, highlighted the value and the need of this process.
To consistently produce high quality products, a quality management system must be practically implemented in every organization. One of its core instrument is to ensure the capability of the measurement systems, which are the basis for decisions regarding the behavior of the product critical quality characteristics. Base on requirements of the quality management system, a Measurement System Analysis should be conducted for all measurement system which are mentioned in the organization quality plan. Most problematic measurement system issues come from measuring discrete data, which are usually the result of human judgment (subjective decision) when categorizing products such as good/bad (visual inspection). It was the aim of this paper to address such an issue presenting a case study made in a local company from the Sibiu region, in order to evaluate how capable are the appraisers to visually inspect steel chains. The results were analyzed using MINITAB statistical software with its module called Attribute Agreement Analysis. The conclusion was that the inspection process must be improved by operator training, developing visual aids/boundary samples, establishing standards and set-up procedures.