АНАЛИЗ КИНЕМАТИЧЕСКОЙ СХЕМЫ ПОРШНЕВОГО W-ОБРАЗНОГО ДВИГАТЕЛЯ С ПРИЦЕПНЫМИ ШАТУНАМИ

This article analyzes the kinematics of a crank mechanism and evaluates the feasibility of organizing the operating process using two-phase fuel injection in a V-engine with trailing connecting rods and identical piston strokes. The advantages and disadvantages of two main connecting rod designs are highlighted, allowing us to evaluate the characteristics of the additional bending moment and the factors influencing its formation. Two main connecting rod designs are considered. The first has an angle between the longitudinal axes of the main connecting rod and its trailing rod equal to 60, while the second has an angle of 67 with a cylinder V angle of 60. A comparative kinematic analysis of the main connecting rod design, performed using the first and second designs, as part of the crank mechanism of a V-2 engine, allowed us to determine the angle between the trailing connecting rod axis and the side cylinder axis, which characterizes the occurrence of an additional bending moment. Several fundamental principles are defined for implementing a two-phase fuel injection system using the first design of the main connecting rod, as well as the injection angles of the pilot and main fuel portions, with the goal of creating an identical operating process to that achieved with the second design of the main connecting rod. The conditions for the fuel injection moment under the influence of negative factors acting on the main connecting rod are graphically presented, as well as the relevance of a two-phase fuel injection system. It is concluded that implementing a two-phase fuel injection system to the cylinders while maintaining uniform piston stroke and minimizing the negative impact of additional bending moment is a promising approach to improving the technical level of V-shaped engines with attached connecting rods.

The rapid development of manufacturing in recent years has led to a significant expansion of the technological capabilities of modern metal-cutting equipment. Therefore, the modern approach to intensifying production requires an advanced fixture design. Design and manufacture of flexible fixtures capable of machining similar shapes and sizes of complex geometry parts reduce setup time. The article aims to design flexible fixtures for parts such as one-piece connecting rods under incomplete locating conditions. The advantages are the minimum number of parts and tool availability for multi-axis machining connecting rods in one setup. This approach, combined with up-to-date machining centers and industrial robots, can increase the production efficiency of manufacturing non-removable connecting rods. This effectiveness is in a decrease in the number of operations by 5–7 times, fixtures—by 3–4 times, and machine tools—by 3–5 times, depending on the type of a non-removable connecting rod and its design features. The numerical simulation results of the proposed fixture design confirmed the comprehensive technological capabilities and dynamic characteristics. Particularly, a decrease in displacements and oscillation amplitudes up to 7% compared to the full-basing locating chart was provided. It is determined that the system “fixture–workpiece” entirely meets all the strength, accuracy, and rigidity parameters, which allows you to perform machining with intensive cutting modes. The amplitudes of oscillations do not exceed the tolerances on the dimensions of these surfaces, established by requirements for non-removable connecting rods, and all displacements are elastic. During numerical simulation, the workpiece position remained stable at all machining steps.

Crackable connecting rods have been widely used in cars’ engines recently. In this method no machining is needed to seperate the connecting rod into two pieces. The main microstructure of the crackable C70S6 steel is pear-lite (%90 of the structure is about pearlite). Changing the microstructure by various heat treatment applications can be economic and technologic alternatives to the use of crackable C70S6 steel. In this study, the effect of the bainitic microstructure of the crackable C70S6 steel is ex-amined. Austempering has been applied to the crackable C70S6 steel and then fracture experiments has been carried out. It has been observed a perfect fracture surface. The hardness value of the fracture surface has been measured. Optical and SEM observations have showed us a perfect upper bainitic microstructure. It has been concluded that bainitic microstructure can be an important alternative to the convensional pearlitic crackable C70S6 connecting rods. DOI: http://dx.doi.org/10.5755/j01.mech.20.3.5384

The manufacturing of different types of cylindrical parts requires loading of parts into baskets for heat treatment operation. This loading process is complex and involves issues relating to geometry, and heterogeneity in the parts and in their processing requirements. The parts loaded for heat treatment often do not utilize the available capacity adequately because layer-loading is accomplished by operator ingenuity. Productivity in heat treatment operation can be increased by improving utilization, which is determined by the loading process. This paper describes the development mathematical model using mixed integer nonlinear formulation for loading of cylindrical parts into baskets. The mathematical modeling considers the exact location of parts to be loaded on the layers with the primary objective of minimizing unutilized volume of the baskets.

Torsional vibration reduction of rotating shafts for multiple orders using centrifugal double pendulum vibration absorber

Determinants of Elite Rowing Performance: Implications for Developing Rowers

Air-cooled automotive engines: J. Mackerle, K. E. english translation by K. Caslavsky. 2nd ed., Czechoslovakia. Printed by Charles Griffin & Co. Ltd., London, 1972. 518 pp. U.S. and Canada distribution by Halsted Press Division, John Wiley & Sons, New York.

A Technical Safety Requirement (TSR) control level verification process was developed for the Tank Waste Remediation System (TWRS) TSRs at the Hanford Site in Richland, WA, at the direction of the US. Department of Energy, Richland Operations Office (RL). The objective of the effort was to develop a process to ensure that the TWRS TSR controls are designated and managed at the appropriate levels as Safety Limits (SLs), Limiting Control Settings (LCSs), Limiting Conditions for Operation (LCOs), Administrative Controls (ACs), or Design Features. The TSR control level verification process was developed and implemented by a team of contractor personnel with the participation of Fluor Daniel Hanford, Inc. (FDH), the Project Hanford Management Contract (PHMC) integrating contractor, and RL representatives. The team was composed of individuals with the following experience base: nuclear safety analysis; licensing; nuclear industry and DOE-complex TSR preparation/review experience; tank farm operations; FDH policy and compliance; and RL-TWRS oversight. Each TSR control level designation was completed utilizing TSR control logic diagrams and TSR criteria checklists based on DOE Orders, Standards, Contractor TSR policy, and other guidance. The control logic diagrams and criteria checklists were reviewed and modified by team members during team meetings. The TSR control level verification process was used to systematically evaluate 12 LCOs, 22 AC programs, and approximately 100 program key elements identified in the TWRS TSR document. The verification of each TSR control required a team consensus. Based on the results of the process, refinements were identified and the TWRS TSRs were modified as appropriate. A final report documenting key assumptions and the control level designation for each TSR control was prepared and is maintained on file for future reference. The results of the process were used as a reference in the RL review of the final TWRS TSRs and control suite. RL concluded that the TSR control level verification process is clear and logically based upon DOE Order 5480.22, Technical Safety Requirements, and other TSR control selection guidelines. The process provides a documented, traceable basis for TSR level decisions and is a valid reference for preparation of new TSRs.

Theoretical model for predicting thermodynamic behavior of thermal-lag Stirling engine

The article considers the phenomena of dynamic loading of automotive transmission parts resulting from uneven operation of the internal combustion engine. Based on the information about the operability and causes of failures of the mechanisms of the power unit and transmission, a method for calculating loads is proposed, taking into account the impact of external and internal power factors. The expediency of differentiated consideration of dynamic loads in the transmission is shown. Keywords vehicle, power unit, friction clutch, torsional vibration damper, transmissions, dynamic load

In December 2008, the International Society for Clinical Hemorheology organized a workshop to evaluate and compare three ektacytometer instruments for measuring deformability of red blood cells (RBC): LORCA (Laser-assisted Optical Rotational Cell Analyzer, RR Mechatronics, Hoorn, The Netherlands), Rheodyn SSD (Myrenne GmbH, Roetgen, Germany) and RheoScan-D (RheoMeditech, Seoul, Korea). Intra-assay reproducibility and biological variation were determined using normal RBC, and cells with reduced deformability (i.e., 0.001-0.02% glutaradehyde (GA), 48 degrees C heat treatment) were employed as either the only RBC present or as a sub-population. Standardized difference values were used as measure of the power to detect differences between normal and treated cells. Salient results include: (1) All instruments had intra-assay variations below 5% for shear stress (SS)>1 Pa but a sharp increase was found for Rheodyn SSD and RheoScan-D at lower SS; (2) Biological variation was similar and markedly increased for SS<3-5 Pa; (3) All instruments detected GA-treated RBC with maximal power at 1-3 Pa, the presence of 10% or 40% GA-modified cells, and the effects of heat treatment. It is concluded that the LORCA, Rheodyn SSD and RheoScan-D all have acceptable precision and power for detecting reduced RBC deformability due to GA treatment or heat treatment, and that the SS range selected for the measurement of deformability is an important determinant of an instrument's power.

In order to solve the problem of insufficient power supply for helicopter and to increase the response speed of engine output power during the climbing process, the research on acceleration optimization control for the integrated helicopter/engine system is conducted. Meanwhile, the optimization control method with remarkable robustness for turboshaft engine based on torsional vibration suppression and min-batch gradient descent-neural network is proposed. The modified notch filter is available to suppress the torsional vibration from the frequency domain. Selecting the maximum output power as the optimization objective, the response speed of the engine output power can increase significantly through relaxing the restriction boundary of power turbine speed and taking into account the constraints of rotational speed, static strength, and temperature. The results show that the optimization control method can effectively reduce the low-order torsional amplitude by more than 70% and can decrease the response time of output power by more than 3s compared with the conventional cascade PID control, which allows the turboshaft engine to reach the potential on the premise of hardly exceeding the limit boundary.

Korea Electric Power Industry Code (KEPIC) has been developed on the basis of referring to the prevailing U.S. codes and standards which had been applied to the electric power facilities in Korea. KEPIC has been applied to the construction of Ulchin Nuclear Units 5&amp;6 since 1997 as per the endorsement of Ministry of Science and Technology, and is being completely applied to the construction of Shin-Kori and Shin-Wolsung Nuclear Power Plants (NPPs) in Korea and of Barakah NPPs in UAE. Although the technical requirements of KEPIC related to design and inspections for pressure vessels have been developed on the basis of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (BPVC), Korea Electric Association (KEA) that is KEPIC maintenance organization is trying to find and improve unreasonable requirements based on the acquired experiences for the continuous construction and operation of NPPs. In the administrative requirements, KEPIC, unlike ASME, adopted not only mechanical field but also electrical field related to NPPs. Furthermore, the qualifying system for services such as Nondestructive Examination, Heat Treatment, Design and Equipment Qualification Organization was adopted to improve safety and reliability for NPPs. In the technical and administrative requirements, KEA has been performing betterment studies such as ‘integration of welding coordinator in welding quality system of KEPIC’, ‘induction of Korean national standards (KS) materials equivalent to ASME/ASTM materials into KEPIC-MH codes’. The result of study for development of Steel-plate Concrete (SC) structure and modularization technique for NPPs has been adopted to 2010 edition of KEPIC-SNG.

Body shell of anti-tank rocket which is a pipe part working under extreme conditions of high pressure and temperature, is manufactured from low-alloyed high quality steel 30X3MФ. The steel 30X3MΦ made in Vietnam appropriates of standard to produce body shell anti-tank rocket. The shell ensure technical requirements of composition, with very low rate of P, S and has good mechanical properties. After casting, steel billets were backward extrusion, includes 3 steps of thinned stamp, heat treatment and drawing processes, body shell fabrication is satisfied requirment of technique for anti-tank rocket shell. Results of fire testing of the body shells are in agreement with that of Russian ammunition. The body shells of anti-tank rocket which were manufactured in Vietnam conditions, satisfied desired technical requirement.

Control of residual stresses with post process in BaTiO3-based Ni-MLCCs