Papers by Keyword: Geometrical Parameters

Abstract: Rubber wood has multiple functions especially in the furniture industry and other wood products such as plywood whereas the sawdust is further processed to become medium density fiberboard or wood plastic composites. These composites are useful yet are unable to become the structural components where mechanical performance is critical. An investigation was carried out to find out the mechanical properties of rubber wood honeycomb core in the fiber reinforced composites with glass fiber as its facesheet and epoxy as its matrix. Cell diameter fabricated at 7 mm with increasing cell wall thicknesses ranging from 1 mm to 3 mm respectively. In the flatwise tensile test, the results showed that the interfacial bonding strength increased by 21.6% with increasing wall thickness. As higher density increased and minimum strength improvement, the specific strength will be reduced. Meanwhile, wall thickness of 3 mm is only 1% away from the sandwich composite with solid rubber wood which has the most similar bonding strength as in climbing drum peel test with lower density.

Abstract: The article describes the strength characteristics of the material used for highly loaded structural elements by modeling their stress-strain state (SSS) and testing special laboratory samples for strength. The typical biaxial SSS is characterized by a different ratio of the main stresses in the focus of possible destruction, which affects the strength characteristics and requires the use of special equipment for determining strength values in laboratory conditions. To create a biaxial SSS under these conditions is a difficult task, since it requires non-standard laboratory samples and test systems with several power drives or complex lever devices for loading these samples, which limits the use of this testing method in determining the mechanical properties of materials. The article describes a simpler method for testing materials under complex stress-strain using special laboratory disc samples on standard test equipment with one power drive. The disk sample design and methods of deforming and creating test conditions are described.

Abstract: In this report, different hybrid Density Functional Theory (DFT) methods were utilized to determine the geometries, total energies, Frontier molecular orbitals, atomic charges, and rotational barriers of 3,5-Diamino-6-(2,3-Dichlorophenyl)-1,2,4-Triazine, C₉H₇Cl₂N₅ molecular system. All optimized geometrical parameters (i.e. bond lengths, bond angles, and dihedral angles) were then compared with the experimental data, which reported by Sridhar and Ravikumar in 2009 [5]. Also, the results of electronic structures (i.e. total energies, Frontier molecular orbitals, atomic charges, and others) obtained by different DFT methods were compared and discussed.

Abstract: In this paper, a first principle Density Functional Theory (DFT) method was conducted to study the geometric and electronic structures of 1-(4-chlorophenyl)-2-{[5-(4-chlorophenyl) -1,3,4-oxadiazol-2-yl] sulfanyl} ethanone, C₁₆H₁₀C_l2N₂O₂S. Using B3LYP level of theory with four basis sets of 6-31G**, 6-31++G**, 6-311G**, and 6-311++G**, the equilibrium structure of the title molecule was used to determine the total energies, Frontier molecular orbital’s energies, Mulliken atomic charges, and others. The computed findings present that four total energies obtained are close to each other, with the corresponding values of-59716.06 eV, -59709.42 eV, -59708.56 eV, and-59716.51 eV, respectively for B3LYP/6-31G**, B3LYP/6-31++G**, B3LYP/6-311G**, and B3LYP/6-311++G** methods. The calculated HOMO-LUMO energy gaps were predicted in the range of 4.001 eV - 4.089 eV. In this study, the atomic charge values of molecular system were also determined using Mulliken Population Analysis (MPA) approach. For DFT/B3LYP/6-311G** level of calculation, the computed results show that the atom of C₈ accommodates the highest negative charge in the title molecular system. All the oxygen, nitrogen, and chloride atoms are having negative charges, whereas all the hydrogen atoms are having positive charges. In addition, the dipole moment value was also determined to be 1.4758 Debye by employing DFT/B3LYP/6-311G** level of theory.

Abstract: In this work, we study the effect of the geometrical and technological parameters on the performance of stacked transformer in crystal metal oxide silicon (CMOS). It also presents the equivalent electrical model of on-chip stacked transformer based on the “2-p” architecture and contains the equations to evaluate its components values. These equations depend on both technological and geometric characteristics of the transformer. The inductance (primary or secondary) and the quality factor (primary or secondary) of on chip stacked transformer depend on the geometrical and technological parameters. We study the effect of the geometrical and technological parameters of on chip transformer, so to establish a methodology of its dimensioning and consequently its integration in a chip. The various geometrical and technological parameters that influence the performance of the transformer: capacitance between primary and secondary coils, oxide capacitance between the (primary coil, secondary coil) and substrate, substrate ohmic loss, and substrate capacitance.

Abstract: The article discusses contact interaction of the straight-edge or radius cutter with the workpiece. Parameters under investigation are as follows: geometry in a setting system, the cutting edge length and a cross section of the shear layer. The description of the main features of the straight-edge cutters is given. Characteristic curves of parameters under investigation are presented. Guidelines for choosing of cutting tools are offered on the basis of the data obtained.

Abstract: In order to achieve the local resonance of flexible-rod whetstone-seat vibration subsystem of the ultrasonic honing device, and using the analysis method of control theory, to regard the flexible-rod and whetstone-seat as the independent part in dynamics, their natural frequency and the vibration displacement function respectively are calculated by adopting the model of vibration with uniform section rod. Then the relationship between the natural frequency and the geometrical parameters of flexible-rod and whetstone-seat are established. The experiments shows that the computed result approximates the actual of flexible-rod whetstone-seat vibration system relatively. For the design of flexible-rod whetstone-seat vibration system with better vibration performance, it has the significant reference value.

Abstract: In the work the results of experimental researches of geometric and mechanical parameters of vertically aligned carbon nanotubes (VACNT) by atomic force microscopy (AFM) and nanoindentation are presented. Here is also shown the influence of diameter and length of the carbon nanotube on the value of bending stiffness and Young's modulus of nanotubes. The analysis of the experimental researches shows that the magnitude of bending stiffness significantly increases with the increasing of the diameter of the nanotubes and decreases with increasing length of the CNT. Diameter and length of the carbon nanotubes also have the most significant influence on Young's modulus of CNTs. The obtained results can be used to develop the processes of formation of micro-and nanoelectronic elements based on the VACNT.

Abstract: This paper present the geometrical parameters were conducted to study how they impact the fatigue of the girders with corrugated web by a comprehensive finite element method. Different parameters, such as the oblique angle of the web, the radius of curvature between the web folds, the thickness and width of flange, the height of the beam were investigated. The research object were : promote the application of this structure, especially for corrugated steel web composite bridges on the fatigue design theory and method provide the standard. The numerical results show that geometrical parameters of girders with corrugated webs have great effect on the stress concentration of weld toes. In addition, weld depth and angle have greater impact on the fatigue of the beams with corrugated webs.

Abstract: The fore-angle and the lateral-rotation angle of PDC core bits, which are two main geometric parameters, have an important influence on the cutting efficiency and performance. Previous studies determined the ranges of two angles mainly depending on the effect of broken rock rather than its mechanical strength to examine the issue. Based on the strength factors, the paper uses finite element program ANSYS to optimize the fore-angle and the lateral-rotation angle of PDC cutters. The main geometric parameters are optimized and the optimal values are obtained under different circumstances, which provides a theoretical basis for reasonable design of the PDC core bits.