Development of Calibration Knives for Hot Cutting Shears

In this paper, the problem distortion the end of a cylindrical workpiece in the cutting process on hot shears before being fed to the piercing mill is considered. To solve this problem, a new calibration of knives has been developed, and a finite element model hot cutting shears has been developed using the DEFORM-3D computer simulation software package. Modeling the cutting process using the proposed calibration has been carried out. It was found that the knife calibers geometry plays an important role in the formation end part geometry of the blank. Based on the simulation results, it was concluded that proposed calibration reduces the ovality workpiece end by almost 2 times in comparison with current calibration. Recommendations have been developed for the production of changes in the existing technology for cutting pipe billets.

Biomechanical grounding of the transalveolar osteosynthesis of еdentulous мandible fractures

The purpose of the work is improvement of the effectiveness of the mandibular fractures treatment in patients with partial or complete adentia by developing and experimentally testing transalveolar osteosynthesis technique. An experimental study was carried out by 3D computer simulation modeling by the final element analysis to assess the efficiency of mandibular fractures fixation at partial or complete adentia using the Ш-shaped plate, which we developed for the transalveolar osteosynthesis method. Calculations of the immobilized fractures for static (own weight) and dynamic (functional) loads were performed according to the author's method, taking into account pronounced resorptive processes in the bone from the beginning of the reparative reaction to assess the rigidity of fragments fixation during the entire period of the fractures healing. Under the conditions of the same three-dimensional model of the mandible, calculations were performed when the fracture was fixed with ordinary linear titanium osseous plates. It is proved that at functional load the new plate provides a compression effect in the fractures region, as evidenced by the negative displacements in the final elements of the mental region according to the results of design load combination 2- 3. The maximum efforts in the screws of the calculation model with a conventional bone plate were 136.955 N, which is almost ten times more than on the model with a Ш-shaped titanium retainer (12.656 N).

Impact of the Application of Computer-Based 3D Simulation on Acquisition of Knowledge of Guidance of Mandibular Movement

Recently, computer-aided three-dimensional (3D) simulation has expanded to modern education. This study aims to investigate the effects of 3D computer simulation on the learning and self-assessment of the guidance of the mandibular movement. Sixty second-grade dental students were randomly distributed into three groups in an occlusion class. Various teaching protocols were used for each group. Students in the first group (lecture (L)) were taught exclusively through a textbook and two-dimensional illustrations. The conventional lecture method followed by computer-aided 3D simulation was applied to the second group (lecture-to-simulation (LtS)). Lastly, students in the third group (lecture with simulation (LwS)) were simultaneously taught using the conventional lecture and computer-aided 3D simulation methods. After teaching each group, a paper-based examination was conducted; actual and expected scores were obtained on the same day as the occlusal class. Analyses of variance with Tukey’s post-hoc analysis were used to compare the teaching protocols, whereas the independent t test was used for comparing between actual and expected scores (α = 0.05). The LwS group exhibited significantly higher actual and student-expected scores than the L and LtS groups (p < 0.001). The expected score was significantly lower than the actual score in the L group (p = 0.035). However, in the LtS and LwS groups, no statistical difference was observed between expected (p = 0.114) and actual (p = 0.685) scores. The distribution of actual scores in the grading systems indicated higher percentages of excellent (grade A) and good (grade B) scores in the LwS (96.7%) and LtS (79.7%) groups, respectively, than in the L group (53.4%). Using computer-aided 3D simulation to teach the guidance of mandibular movement improved the learning outcomes and self-assessment of students, especially when 3D simulation was combined with conventional lecturing.

Electrically Coupled Folded Arm Resonators with the Feedline Patch Antenna for Spurious Harmonic Suppression and Bandwidth Improvement

This paper presents a new design of the filtering antenna with a quasi-elliptic function response. The basic structure of the proposed filtering antenna is consists of a four-folded arms open-loop resonator (OLR). The proposed filtering antenna is simulated, improved and, analyzed by using 3D Computer Simulation Technology (CST) electromagnetic simulator software. The design has good spurious harmonic suppression in the upper and lower stopbands. The Insertion Loss of the proposed filtering antenna IL=0.2 dB and the Return Loss RL= -25.788 dB at the center frequency fo=5.75 GHz. The passband bandwidth which is relatively wide, and equal to 0.793 GHz. The microstrip filtering antenna circuit shows good design results compared to the conventional microstrip patch antenna. The filtering antenna design circuit with etched ground plane structure also has good design results compared to the filtering antenna design which has a complete ground plane structure.

Scientific and methodological bases of rational design of hoisting-and-transport machines metal structures

Purpose of this paper is to improve parameters of metal structures elements of hoisting-and-transport machines (HTMs) by means of systematic approach to study changes of their stress-strain state during design or usage stage. Subject of the study is pattern of changes in distribution and values of stresses in elements of metal structures of HTMs depending on the structural and parametric characteristics. Design methodology of metal structures of HTMs on the basis of a portal crane is proposed, it is based on strength calculations using methods of allowable stresses and FEM, 3D computer simulation, system analysis of the stress-strain state and structural-parametric synthesis. Results of modeling of loading state and calculations of the portal crane metal structures on strength by FEM in CAD/CAE system, analysis of their stress-strain state, structural-parametric synthesis are presented. Recommendations on practical application of the results are given. Possible ways of further development of proposed solutions are identified.

Теоретическое и экспериментальное исследование миниатюрной планарной замедляющей системы на диэлектрической подложке для лампы бегущей волны W-диапазона

The research results of a miniature meander planar slow-wave structure (SWS) for W-band traveling wave tube are presented. 3D computer simulation of the electrodynamic parameters of SWS has been carried out. A new technology of manufacturing of planar microstrip SWS has been presented. An experimental research of the S-parameters of an SWS has been carried out. The results show good agreement with the results of 3D simulation. The output characteristics of the TWT with sheet electron beam and planar SWS on dielectric substrate were simulated.