Author: Mahmure AVEY, Elçin YUSUFOGLU, Yusif HASANOV, Eckart SCHNACK, Kemal ERTUNÇ
Email: email@example.com, elçin.firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com
Abstract: In this study, the dynamic behavior of shear deformable heterogeneous nanocomposite sandwich cylindri-cal panels containing carbon nanotube (CNT) patterned layers is investigated. The basic differential equa-tions of the sandwich cylindrical panel composed of CNT patterned layers based on the Donnell type shell theory are derived. Then basic equations are solved by applying Galerkin method and obtained expression for the nondimensional free vibration frequency of three-layer nanocomposite cylindrical panels within the first order shear deformation shell theory (FOSDST). Finally, the influences of transverse shear strains, volume fractions, arrangement of sandwich nanocomposite layers on the nondimensional free vibration frequency are studied.
Keywords: Carbon nanotube, nanocomposite, sandwich panel, free vibration, frequency, shear deformation theory
Author: Rasim ALIZADE, Arkadiy TEMIROV, Allahverdi ALAKBAROV
Email: firstname.lastname@example.org, email@example.com, firstname.lastname@example.org
Abstract: The article identifies some areas of engineer’s background, which are not sufficiently covered in curriculums of national universities. These gaps mainly relate to issues of clear understanding of real engineering and design processes, capability to apply system thinking approach to realization of engineering tasks, which is basis of systems engineering. Properly configured curriculums will allow students smoothly move forward from basics of engineering processes and disciplines up to Engineering Project Management..
Keywords: Engineering Design, Curriculum, System Approach, System Engineering, Engineering Design Process, Syllabus
Author: Fatih Cemal CAN, Hayrettin ŞEN
Abstract: In this research, computer controlled two DoF five bar robot manipulator is investigated. In order to control manipulator, a human machine interface program is developed in Visual C# after completing inverse kinematic analysis of robot manipulator. By the help of inverse kinematics, this program calculates two joint variables for given positions of end point. Then the program sends a data package containing these joint variables to Arduino microcontroller. Arduino microcontroller set the positions of two servos according to calculated joint angles. Also using standard geometries, robot can follow trajectory a line, a circle and a rectangle. Furthermore, a lot of patterns can be generated using function with variable radius and angle of rotation.
Keywords: two DoF Robot, five bar, linkage mechanism, Arduino, Visual C#
Author: Nazim MIR-NASIRI
Abstract: There are many methods of identifying general stability of complex dynamic systems. Routh and Hurwitz’s criterion is one of the earliest and commonly used analytical tools analysing stability of a dynamic system. However, it requires redundant calculation of all the elements of the Routh array to identify stability, even the low-order system. Therefore, it is not a simple method to identify, especially analytically, the stability boundaries for the coefficients of the characteristic equation due to tedious and lengthy derivation of all the Routh array elements. The proposed brand-new criterion or algorithm is an effective alternative and a universal technique to identify analytically the stability of up to sixth-order linear time-invariant dynamic system based on the set of unique for all possible system equations (2) and (3) that relate coefficients of the system characteristic polynomial at the stability boundaries by means of a single additional constant k. The expressions derived on this basis for a higher-order dynamic system can be used effectively to identify the boundaries of its stable behaviour spans. It defines the necessary and sufficient conditions for absolute stability of higher-order dynamic systems. It also allows the analysing of the system’s precise marginal stability condition (whether stable or not) and the nature of the system roots at the stability boundaries, i.e. when they are relocated on imaginary jω-axis of s-plane. The criterion proposed by the authors, in contrast to Routh criteria, simplifies significantly the identification of maximum and minimum stability limits for any coefficient of the higher-order characteristic equation. The paper also presents the numerical analysis of stability boundaries for systems with order higher than six based on criteria (2) or (3). The derived stability boundary formulas (2) and (3) for the polynomial coefficients are successfully used for PID controller gains selection in close-loop control systems and this achievement does not have analogy in control theory.
Keywords: higher-order dynamics, characteristic polynomial, stability boundaries, absolute and marginal stability.
Author: Şebnem GÜR, Koray KORKMAZ, Gökhan KİPER
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Abstract: As they constitute a substantial percent of deployable structures, scissor mechanisms are widely studied. This being so, new approaches to the design of scissor mechanisms still emerge. Usually design methods consider the scissor elements as modules. Alternatively, it is possible to consider the loops as modules. In this paper, loop assembly method is used such that antiparallelogram loops are placed along a circle, to construct a deployable structure. The research shows that it is possible to construct radially deployable structures with identical antiparallelogram loops with this method. Then kinematic and geometrical properties of the construction are analyzed. It is found out that the links of such a structure turn out to be similar generalised angulated elements. Furthermore, similar loops are used for the construction and deployable rings are obtained.
Keywords: deployable ring-like structure, antiparallelogram loop, loop assembly method, radial expansion, angulated scissor element.
Author: Anar HAJIYEV
Abstract: In article carried out a kinematic study of a new constructive solution of pumping unit, which used in oilfield and the influence of the direction of rotation of the crank on the kinematic characteristics of the rod suspension point and extreme forces in both axial and deaxial-converting mechanisms was evaluated. Studies have shown that, according to the elementary theory, changing of direction of rotation of the crank does not affect the load on the rods suspension point, but according to the refined theory, the direction of rotation of the crank has a significant effect on the operation of the pumping unit. Because in this case, the laws of motion of the rods suspension point is sharply change. In addition, it was found that the fundamental difference between the axial and deaxial-converting mechanisms is due to the change in average speed during the up and down stroke movement of the rods suspensions point. It has been found that on pumping units with positive deaxial-converting mechanisms when the crank rotates clockwise, the rods suspension point moves upstroke faster than when it moves down, or vice versa, when the the crank rotates counterclockwise, the time at which the rods suspension point moves up is later than when it moves down. On pumping units with negative deaxial transforming mechanisms when the crank rotates clockwise, upstroke time of rods suspension point is less than it is downstroke time. And on pumping units with negative deaxial transforming mechanisms when the crank rotates clockwise, the upstroke time of the rods suspension point is longer than when it moves down and vice versa, when the crank rotates counterclockwise, the upstroke time of the rods suspension point is less than when it moves down.
Keywords: pumping unit, axial, deaxial, rods, block, crank.
Author: Alishir ALIFOV
Abstract: The dynamics of a cam mechanism with delays in elasticity and friction is considered, the operation of which is supported by an energy source of limited power. The interaction between the cam mechanism and the energy source is described by nonlinear equations. To solve these equations, the method of direct linearization is used and the equations of non-stationary and stationary motions are derived. Relationships are obtained for calculating the stationary values of the amplitude and phase of oscillations, the speed of the energy source. A number of calculations have been performed in order to obtain information on the effect of delays on the dynamics of the cam mechanism.
Keywords: cam, dynamics, oscillations, delay, elasticity, friction, energy source, limited excitation.