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Method of calculating the design parameters of a modulator anti-lock braking system with a high flow of working fluid

100%

Zhilevich M. , Ermilov S. , Kapski D. , Vovk Y. , Lyashuk O. , Vovk I.

tom z. 110

199--210

The design dimensions of the executive hydraulic cylinders of the brake system of heavy-duty mining dump trucks cause high fluid flow during the braking process. Therefore, dimensions of the anti-blocking system modulator spool pair require unique electromagnets or hydraulic amplifiers to control. These solutions do not allow the required modulator performance. Thus, a modulator scheme with a division of the flow of fluid from the source to the brake cylinders was developed. This scheme allows during emergency braking passing, an additional amount of fluid to cylinders through the valve, installed parallel to the main valve upon pressure increase phase and controlled by the pressure difference. The task is to develop a method for calculating the main structural dimensions of a modulator. The calculation of the valve of the second cascade, installed in parallel to the main stage, is carried out for the emergency braking mode with the maximum flow rate to ensure the required performance of the braking system. The balance of fluid flows equations is compiled at the key points. The flow rate of the fluid through each of the valves is determined by the Torricelli formula, and the pressure difference across the valves is assuned equal. The obtained relations allows building a family of Q-p curves, which can be used to select the diameter and stroke of the additional valve depending on the flow rate in the brake system.

Complex evaluation of the efficiency of urban consolidation centers at the micro level

100%

Savchenko L. , Grygorak M. , Polishchuk V. , Vovk Y. , Lyashuk O. , Vovk I. , Khudobei R.

tom z. 115

135--159

A methodical approach for the determination of economic and socio-environmental costs in the application of the city consolidation center at the micro level was proposed and tested on real data. Two options of urban delivery of small shipments are considered, in particular, for e-commerce - direct delivery and delivery through the micro-consolidation center. The system of indicators proposed in this work allows a detailed assessment of the economic component of direct and consolidated delivery, including transportation costs, the functioning of the consolidation center costs and costs for pedestrian delivery to the residential district customers. Socio-economic indicators allow considering the interests of other residents of the city, suffering from a dense traffic flow and harmful emissions from freight vehicles. The proposed method of integrated assessment was tested on real data of a micro district of the city. The results made it possible to estimate the proportion of each component of expenditures in the economic, socio-environmental and total costs for both delivery options. The analysis of the sensitivity of costs to changes in the input parameters showed the difference in the strength of influence, and the rating of influencing factors. The proposed method allows us to estimate the economic costs of all participants in the urban delivery process for small shipments, as well as to prove the rationality of using micro-consolidation to serve a micro district of a large city.

The study of stress-strain state elements of the truck semi-trailer body bottom

100%

Lyashuk O. , Levkovych M. , Vovk Y. , Gevko I. , Stashkiv M. , Liubomyr S. , Pyndus Y.

tom z. 118

161--172

Research on the influence of geometric parameters of body bottom elements on the stress-strain state (SSS) of the truck with the general application of computer simulation methods was conducted. The nature of the change in static stress and displacement depending on the change in the proportions of the crosssection of the channel at fixed geometric dimensions of the workpiece and the thickness of the workpiece and the bottom material of the body has been studied. Analytical, numerical and experimental methods were used in the study of the stress-strain state of the metal structure of car bodies. Its weight minimization is an important aspect of a truck body design. Because an excess weight leads to increased production costs, reduced payload and reduced fuel efficiency. According to the concept of weight reduction with the provision of a given strength, the body model with variable parameters of the bottom elements is modelled and analyzed. CAD - body models and analysis of the stress-strain state of the channels of the bottom of the bodies have been performed using the software package SolidWorks.