Abstract: The tire model validity factors are listed and discussed when using tires in complex multi-mass vehicle models. Complex vehicle system models are used to estimate (to forecast) their handling and stability properties (including Electronic Stability Control (ESC) performance). It should be as less as possible discrepancy between vehicle virtual computational and experimental tests results. The objective forces to create more complex vehicle models. A tire is known to be the one of the most significant elements in the model and to influence considerably on vehicle handling and stability factors transmitting all road reactions. The paper describes factors to be able to get influence on the PAC2002 pneumatic tire model validity when simulating it in MSC.ADAMS/Car Software. The tire model creating begins by conducting studies of rolling tire characteristics. The studies are examined on tire benches. Conducting experimental studies there are the set of factors to be able to bring a measurement error into study results. The analysis of various literary sources has permitted to choose three basic factors to be able to get influenced on tire model and all the vehicle model validity. Among these factors there are following: tire pressure, tire temperature и tire tread wear. The most significant of these factors is the tire pressure. For providing required study accuracy it needs to apply tight restrictions on each factor changing range influencing on rolling tire characteristics. The ranges are to be determined for each certain tire model by using study results.
Abstract: This study investigated optimum design methods for frame buildings with focus on minimization of economic costs. The methods discussed are intended to provide sufficient reserves for reliability of load-bearing steel structures. The analyzed mathematical models enable to assess seismic resistance of a structure and implement optimum design methods according to the selected key criterion. The available mathematical models assessing economic efficiency of metalwork reinforcement need further development. The model based on the principle of balanced risk is considered as the most appropriate for the study of structural reliability for industrial buildings. This model allows to assess the expected damage as compared with the initial spending on seismic protection. The focus is on setting and implementation of the task whose limiting condition provides equality between expenditures for reinforcement of damaged steel structures and those for damage prevention activities. Minimum of economic costs for construction or reconstruction of a structure is taken as the optimality criterion. This takes into account accumulation of damages within the standard life cycle and changes in stiffness of materials. Assessment of damage risk is based on the life cycle of a structure, its seismic resistance class and spending on damage repair. The study suggests a number of structural solutions that enable to reduce deformation of steel parts of the frame.
Abstract: Article is devoted to a research of aerosol systems of supply ventilation. Expediency of creation and use of water and aerosol systems for decrease in concentration of fine-dispersion dust in working zones, and as a result, decrease in negative impact on operators of various productions is proved. The design of a centrifugal mechanical one-slot-hole nozzle is proposed. Problems of dust content in air of a working zone and impact of particles of PM10 and PM2,5 on an organism of workers are considered.
Abstract: The paper presents the results of the assessment of atmospheric air pollution with fine dust РМ10 studies in the city of Kabul. The investigation was based on concentration of fine dust РМ10 measurements that were conducted by the national agency on ecology and environmental protection of Afghanistan and by Russian researchers in summer and autumn of 2015. It is shown that, according to the Chi-square and Kolmogorov-Smirnov criteria, the best law for the distribution of the maximum daily dust concentration is the logarithmic normal law. For the maximum daily concentration (РМ10) a density function and an integrated distribution function have been summarized. A mathematical model of the concentration of fine dust (РМ10) dependence of three factors: wind speed, humidity and temperature have been obtained. On the basis of F–Fisher criterion the quadratic model has been chosen for June and August, and the linear model has been chosen for July, September, October and November.
Abstract: It was proposed to use air flow screw straightened units in outlet pipe of the dust collectors to reduce the aerodynamic resistance of exhaust ventilation systems. It is allowed to decrease power consumption for their maintenance operation consequently. The article describes the results of experimental studies to evaluate its effectiveness by applying the tangential screw straightened unit within ventilation system. The obtained results showed that the use of this device allows reducing the aerodynamic resistance of the cyclone by 14.6%, and for counter-swirling flows’ dust collector (CSFC) by 17.2-23.6%. It was found that meanings of the aerodynamic resistance depend on value the share proportion of the flow entering into lower CSFC apparatus’ input.
Abstract: On the basis of results of natural-technical system’s researches «Natural Environment - Object of Activity – Population» on the use of water resources, the predominating integrity role as the dominant principle of functioning of this class of systems is determined.
Abstract: The article presents the results of applying environmental mechanics in research of absorber for capturing emissions’ hydrocarbons vapors exhausting from the gas station into the atmosphere air. Often residential human habitants are located within the boundary of the sanitary protection zone (SPZ) of these gas filling stations. The analysis measurement’s and stratification’ modeling results these gas emissions’ in the atmosphere showed that benzene and xylene vapor’s concentration in the atmosphere exceeds the existing sanitary-hygienic norms for these ingredients often. There presented the research results of the proposed aspiration schemes was equipped absorbing device for the capture of gas vapor’ emissions at the gas station in this article. It was obtained the regressions of capture effectiveness for the proposed device by mathematical processing. The research results were implemented for design of pilot industrial set up that was installed and successful tested in one of the gas filling station in Russia. It was showed the reliability of the proposed device for practical commercial use.
Abstract: The characteristics of the lateral nonlinear vibration in composite shaft-disk rotor system with nonlinear deformation are studied. Firstly, the equations of the kinetic energy of the composite shaft, the disk and the eccentric mass as well as the equations of the strain energy of the composite shaft are derived. Based on these equations, the nonlinear vibration equations are deduced by using the Lagrange equation. Then, the frequency response curves and time response curves of the system are obtained by using the IHB method and verified by the fourth order Runge-Kutta method. Experimental results show that the external damping coefficient, the size of eccentric mass only influences the nonlinear amplitude. Moreover, the ply-angle, thickness to diameter(T/D) ratio, length to diameter (L/D) ratio, and the position of disk in the shaft not only produce an effect on the nonlinear amplitude, but also influence the nonlinear vibration frequency.
Abstract: This research focuses on influence of pore structure on chloride distribution in surface layer of cement paste under cyclic wet-dry condition. The results of chloride distribution reveal that drying and wetting cycles can lead to a peak value of chloride content (Cmax) occurring in surface layer of cement paste. Cmax increases with the increase of W/C. While the depth (Δx) at which Cmax appears does not show a regular change. Moreover, Cmax should be used to predict service life of concrete structures when Cmax appears in the chloride profiles. For the influence of pore structure, there exists an obvious hyperbolic relationship between chloride diffusion coefficient (D), Cmax and pore structure parameters. D and Cmax increase with total porosity and the most probable pore diameter, decrease with tortuosity, and stabilize gradually. And the most probable pore diameter has the most significant impact on D and Cmax. In addition, XRD and SEM-EDS results indicate that the deposition of Friedel’s salt results in the formation of more inkbottle shaped pores, which may cause the appearance of Cmax under cyclic drying-wetting conditions due to hysteretic moisture effect.
Abstract: This study presents results of an experimental investigation conducted to investigate the mechanical properties of sisal and glass fiber reinforced concrete. Four basic concrete mixes were considered: 1) Plain concrete (PC) containing ordinary natural aggregates without any fibers, 2) sisal fiber reinforced concrete (SFRC), 3) sisal and glass fiber reinforced concrete (SGFRC), 4, glass fiber reinforced concrete (GFRC). Investigated properties were compressive strength, splitting tensile strength, flexural tensile strength and workability. The results of fiber reinforced concrete mixes were compared with plain concrete to investigate the effect of fibers on the mechanical properties of fiber reinforced concrete. It was determined that addition of different kinds of fibers (natural and synthetic) is very useful to produce concrete. The addition of fibers was resulted into higher compressive strength, splitting and tensile strength. However, the workability of the fiber reinforced concrete was found lower than the plain concrete due to the addition of fibers in the concrete.