scientific edition of Bauman MSTU
SCIENCE & EDUCATION
Bauman Moscow State Technical University. El № FS 77 - 48211. ISSN 1994-0408
Automated control system for the contact wire’s wear
# 01, January 2014
During the exploitation of railway roads it’s necessary to automate condition monitoring of the overhead system. Beside other parameters, it’s important to check the contact wire’s wear. Precision, sensitivity and performance efficiency of existent technical solutions are limited. The purpose of this work was a development of automated control system for the contact wire’s wear. Operational circumstances require noncontact measurements. Proposed system is based on a use of electro-magnetic (eddy current) method of non-destructive control. The width of contact area between a wire and a pantograph collector was selected as an information-bearing parameter. This system includes a matrix eddy current sensor which consists of 30 eddy current transducers, placed at the pantograph collector, high-frequency generators and signal processing system. Obtained measurement data are transferred to the mobile laboratory’s computer through a fiber-optic carrier line. Further processing and database creation allows one to monitor the condition of a contact wire constantly.
Development of a systems approach to optimization of management of the aggregate value of transportation system
# 09, September 2012
Enterprises aimed at constant improvement of competitiveness of their products face a constant challenge to optimize the aggregate value of their operations. The author presents an approach to development of an organizational and economic model which allows a company to evaluate its activities in terms of its efficiency in the logistics infrastructure. The author describes an integrated solution to this problem by means of the developed algorithm and describes the necessary actions for each step of the algorithm. As an example of solving optimization of operational costs of an enterprise, the author analyzes inputs of the transport system.
Evaluation of key performance indicators by the example of an integrated supply chain
# 10, October 2012
Currently, most Russian companies, in contrast to advanced Western companies, seek to maximize profits in a short-term period. However, in the long-term outlook, such an approach is unprofitable. Evaluation of effectiveness of the supply chain is not possible without development of a regular system of key performance indicators. A set of key performance indicators depends on many factors, including the specific character of the industry; that’s why a set of key performance indicators can not be standardized and should be designed with due account of the specific character of each particular situation. The article describes and analyzes existing approaches that can be efficiently used to assess efficiency of the supply chain; it describes key performance indicators in the case of a "standard" and a "green" supply chain.
Evaluation and comparison of longevity of rods made of steel and titanium alloy in high power aircraft engine
# 08, August 2012
The authors present results of calculations of endurance of connecting rods in high powered aircraft diesel engine made of titanium alloy BT6 and steel 36MnVS4 which is widely used in the automotive industry. On the basis of these calculations the author makes a comparative evaluation of durability of connecting rods under the assumed engineering processes. There is also assessment of the engine weight reduction and of the level of stress on mating parts.
Control characteristic of power steering gear reaction effect
# 08, August 2012
Designs of power steering gears with a reaction effect are used in off-road trucks. In this article the author investigates a regulating system for reaction effect of hydraulic type power steering gear of a cross-country cargo carrier and justified the characteristic for the regulating system of hydraulic booster reaction effect. The author also introduced a concept of coefficient of informativeness. The mathematical model of steering control and the numerical experiment method were used. The author proposes a regulation method allowing to neglect reactive elements and simplify the design. The results presented in this paper could be used for developing perspective steering systems for trucks which are similar to those discussed and operating under similar conditions.
Justification of design parameters of steering gear for rear-steering vehicles
# 07, July 2012
Design and parameters of steering system are the main factors of maintaining controllability and stability of the vehicle. The subject of this paper is the steering system of a three-axle vehicle with steered front and rear wheels. Calculated relations for determination of the required ratio between the front and rear steered wheels’ rotation to ensure controllability and stability of a car were obtained. Recommendations on control parameters for wheel turning were drawn; a new steering control scheme was also proposed. The results presented in this paper can be used for upgrading off-road trucks which are similar to those discussed and operating under similar conditions.
Analysis of factors influencing the formation of supply chain subject to constrained logistic infrastructure
# 05, May 2012
Decision making process regarding the structure of supply chain is influenced by a set of factors which can be conditionally classified as structural, commercial, operational and functional. The author describes the developed factor model which allows systems analysis of factors influencing the formation of supply chain. Special attention is paid to the factors which have became important only recently; they are factors connected with the type of transported goods and possibility of combining different transporting types in the supply chain. For estimation of these factors a multi-criteria mathematical model was developed. This model allows to select an optimal supply chain variant considering the constrained infrastructure.