Applied Mechanics and Materials Vol. 859

Abstract: During their use, optical fibers are subject to harsh installation and environmental conditions. To evaluate more precisely the lifetime of an optical fiber, it is necessary to study the mechanical behavior of optical fibers under extreme conditions, in particular under mechanical and thermal stress.This paper presents the results of new silica optical fibers aged in hot water between 20°C and 70°C and subjected to mechanical static bending stresses from 3 GPa to 3.5 GPa. Thermal dependence of the time to failure was observed. This dependence can be described by the Arrhenius model, where the activation energy is one of the main physical characteristic.

Abstract: The effects of micro-abrasion wear on the surface roughness of molybdenum coatings deposited by electric arc thermal spray on steel support were investigated. The 2D surface roughness was measured and correlated with the experimental results of the micro-abrasion tests. Different worn surfaces which correspond to running-in and steady stage of wear were investigated in terms of the microstructure, 3D image and 2D surface roughness. The micro-abrasion tests were made in the presence of a SiC abrasive slurry for test durations between 200 – 1600 s and the worn surfaces were evaluated by scanning electron microscopy and stereomicroscopy.

Abstract: Fused Deposition Modeling (FDM) or also known as RepRap (Replicating Rapid Prototyper) is a technology that is synonym with 3D printing. This technology has entered a new era with an increasing demand among the community. It has grown commercially in the market of open-source system and it is relatively low cost. Many efforts have been put towards the development of the system in both hardware and software to increase the quality and the performance. The research highlights the development of a new nozzle to evaluate the performance on dimensional accuracy in comparison to the original nozzle. The nozzle emphasizes the die angle for the polylactic acid (PLA) material, the liquefier design which provide constant heat in the liquefier chamber, as well as insulator for the liquefier using highly insulated material. The dimensional accuracies of both nozzles were compared where the result showed that the new nozzle provided better accuracy and stability on the extruding PLA material.

Abstract: The paper presents the background and objectives of a new research project carried out in the field of in situ gas turbine combustion. An extensive literature review highlighting the state-of-the-art in the field is presented. Several possible solutions for the turbine burner are also included. The objectives and the expected original contributions of the projects conclude the paper.

Abstract: The paper deals with the structural synthesis and kinematic analysis of bi-mobile mechanisms used in robotics and other industrial equipment when a suitable curve is necessary to be described in a manufacturing process. The design method is illustrated step by step for a bi-mobile mechanism design. The parameters obtained through the analysis of the inverse model may be used for the system command and control.

Abstract: On the basis of the force analysis of two mobile mechanisms containing a mobile closed contour the theoretical preconditions of creation of self-adjusted mechanisms is developed. The load design of mechanism is executed on the basis of the proved theorem of a derivative on a time from the force moment. Brand new property of self-adjustment is found. Mechanism self-adjustment allows it to be independently conforming to variable external loading by change of speed. Property of self-adjustment allows creating the mechanisms with variable transfer ratio depending on loading. Self-adjusted mechanisms are simple on the device and are working without a control system. Self-adjusted mechanisms (for example, self-adjusted gear boxes) are determining a new highly effective generation of drives of machines with variable technological resistance.

Abstract: Aeronautic industries, medicine, automotive industries are domains in which the composite materials are very important. In orthopedics and orthodontist domains, titanium and its alloys are very used, because their mechanical properties are similar to bone tissue. Bio-composite sandwich beams have high stiffness in flexion and good thermal characteristics. The analytical calculus for bending bio-composite beams is very important. We calculate the arrows for sandwich beams for two aspects: first – beam in four kinds of alloys (titanium alloys, stainless steel, aluminum alloys, Co-Cr-Mo alloys) and second – bio-composite sandwich beam, composed of two equal layers in same alloys and heart in: polyurethane foam, polystyrene foam, epoxide, phenolic, polyester, polyamides, balsa 1 and balsa 2 and compare its.

Abstract: In Computational Fluid Dynamics (CFD) we have to deal with various types of phenomena with strong discontinuities at different length scales like turbulence or hypersonic flows. It is essential that the numerical techniques must provide accurate approximation to calculate the time and space-derivatives. This paper focuses on the behavior of the solution of some known numerical schemes in comparison with analytical solution provided here for the first time, applied on one-dimensional conservation law with different fluxes and non-usual different initial conditions. The results are very interesting in the sense that methods which report very good results on classical tests schemes were not able to accurately predict solutions that admit discontinuities and sharp gradients inside.

Abstract: This main purpose of this paper is to develop an algorithm to find the shortest path on a network in which the weights of the edges are represented by bipolar neutrosophic numbers. Finally, a numerical example has been provided for illustrating the proposed approach.