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Abstract

The objective of this study is to present a numerical modeling of mixed-mode fracture in isotropic functionally graded materials (FGMs), under mechanical and thermal loading conditions. In this paper, a modified displacement extrapolation technique (DET) was proposed to calculate the stress intensity factor (SIFs) for isotropic FGMs. Using the Ansys Parametric Design Language APDL, the continuous variations of the material properties are incorporated by specified parameters at the centroid of each element. Three numerical examples are presented to evaluate the accuracy of SIFs calculated by the proposed method. Comparisons have been made between the SIFs predicted by the DET and the available reference solutions in the current literature. A good agreement is obtained between the results of the DET and the reference solutions.

Abstract

In the industrial sectors, pipelines have been used as the most economical and safe means of transporting oil and gas (Pipelines). However, the number of accidents has increased considerably as their use has increased. As a result of the operating load and the pressure used, the thickness of the tube must be increased and the mechanical characteristics improved. This approach was applied to predict the growth of crack effect in samples of two pipelines at given thicknesses and pressures. We created cracks with deferential dimensions in both API X80 steel pipelines, with an application of deferential internal pressures. For the simulations, we used the code ANSYS.

Abstract

Aluminum alloy is a very useful material in light manufacturing. Friction stir welding (FSW) is a solid state assembly process that is achievable for this material. This work aims to characterize the quality of the weld joint by an operation of shaping (folding), it aims to study the rate of elastic return in this weld joint after a folding operation. In this context, the elastic return for the folding process has been modeled using experimental tests under optimal welding conditions.

Abstract

In this work the structure and properties of composite rollers with surface layer made of hard alloy were studied. The rollers were made by the powder metallurgy method with sintering during pressing and the presence of a certain liquid phase during sintering (semi-liquid sintering). WC-Co and TiC-Ni-Fe materials were used as hard alloys. Iron-carbon and iron-nickel materials were used as soft base. All of the composite layers were formed in one process. The structure of base materials and border layer of these composites were studied. Investigations of thermocycling sustainability of these composite samples were carried out.

Abstract

The subject of the article is the suitability analysis of a measuring system, specifically the Zeiss MMZ T 20 30 16 coordinate-measuring machine utilizing an extended procedure.

The article outlines the measurement preparation process and presents the research station as well as the procedure for determining Repeatability & Reproducibility (R&R).

Abstract

The utility model discussed in this study discloses a wood lathe balancing rest that is advantageous in terms of design, ergonomics, and functions. The study aimed to fabricate a safety device for the wood lathe machine to prevent kickback and slow down vibration from the workpiece attached to the lathe machine to avoid the vibration of the workpiece and to avoid an accident to the operator and to avoid damage of the materials. The utility model is planned not exclusively to spare time yet also for the wellbeing of the laborers amid activity. It is designed to hold the workpiece when turning and control the vibration, it can be mounted on the bed of the lathe near the center of the turning planetary.

Abstract

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.

Abstract

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.