MODELING THE OPERATION OF A RECUPERATIVE SPRING-HYDRAULIC FIFTH-WHEEL COUPLING LOCATED IN THE SEMITRAILER OF LUMBER TRUCK

The substantiation of the necessity of using timber trucks, consisting of timber tractors with semi-trailers, when transporting timber, is given. Attention is focused on improving the efficiency of the functioning of log trucks by con-structive improvement of the fifth-wheel couplings used in them. The analysis of scientific works of foreign scientists engaged in the study of the influence of fifth- wheel coupling on the efficiency of log trucks is carried out. A promising scheme of a recuperative spring-hydraulic fifth-wheel coupling, located in the front part of the semi-trailer frame of a timber tractor, is proposed, which has significant advantages in comparison with other similar devices. At the first stage, a mathematical model of the proposed fifth-wheel coupling was developed; at the second stage, a computer program for a preliminary assessment of the efficiency of the functioning of a timber tractor with a semitrailer equipped with a recuperative spring-hydraulic fifth-wheel coupling is made. The dependences of the change in the average values of the recuperative power and longitudinal acceleration of the trailer relative to the timber tractor on the inner diameter of the hydraulic cylinders of the recuperative device, the mass of the semi-trailer and the frequency of braking and accelera-tion of the timber road train are obtained. It was revealed that the optimal diameter of the hydraulic cylinders of the recuperative device for the given conditions, providing the maximum recuperative power, should be in the range of 50-60 mm. It was found that with an increase in the mass of a semitrailer of a logging tractor, as well as with an increase in the frequency of braking and acceleration, an increase in the recovered power is observed

Numerical analysis of vibration modes of a qPlus sensor with a long tip

We study the oscillatory behavior of qPlus sensors with a long tilted tip by means of finite element simulations. The vibration modes of a qPlus sensor with a long tip are quite different from those of a cantilever with a short tip. Flexural vibration of the tungsten tip will occur. The tip can no longer be considered as a rigid body that moves with the prong of the tuning fork. Instead, it oscillates both horizontally and vertically. The vibration characteristics of qPlus sensors with different tip sizes were studied. An optimized tip size was derived from obtained values of tip amplitude, ratio between vertical and lateral amplitude components, output current, and quality factor. For high spatial resolution the optimal diameter was found to be 0.1 mm.

SIMULATION MODEL FOR ESTIMATION OF FOREST TRUCK PERFORMANCE EQUIPPED WITH RECUPERATIVE SPRING-HYDRAULIC FIFTH-WHEEL COUPLING

The current state and advantages of timber road transport in comparison with other types of transport used for hauling timber are presented. The factors influencing the rational choice of the rolling stock of timber trucks are given. The efficiency of using timber trucks with trailers for transportation of timber has been substantiated. Difficult conditions for the transportation of timber along timber roads, which affect the operability of the towing devices of timber trucks with trailers and the efficiency indicators of timber trucks in general, have been considered. A brief analysis of the work of foreign scientists in the field of increasing vehicle efficiency equipped with various towing devices is presented. A perspective scheme of a recuperative pneumo-hydraulic towing hitch has been proposed to eliminate the identified shortcomings of the considered designs of towing hitch devices. A mathematical model and a computer program based on it have been developed to assess the operability and efficiency of the proposed device, as well as to determine its optimal design parameters. On the basis of the performed computer experiments, it was revealed that the recuperative pneumo-hydraulic towing device allows recuperating the power of 4.7 kW at the maximum acceleration of the trailer relative to the timber truck 0.94 m/s2 when moving a timber truck with a trailer on a model timber road. It was found that the optimal diameter of the plunger cavity of the device, at which the recuperation system provides balanced effective damping, is 49 mm. It has been established that the maximum recuperative power is achieved at a speed of movement of a timber truck with a trailer equal to 32 km/h

Stability Analysis on the Long-Term Operation of the Horizontal Salt Rock Underground Storage

The construction of the vertical cavern in the salt dome deposit can meet the requirements of both storage capacity and tightness. However, if the vertical cavern is still used as the design shape of the salt rock underground storage in the layered salt rock deposit, the high design capacity cannot be guaranteed while the tightness is satisfied. In this case, the use of a large-span horizontal cavern as the design shape of the salt rock storage can not only effectively increase the design capacity of the storage, but also solve the problems such as the stability and tightness of the storage during the operation period by improving the structural form and working mode. Based on this, the ellipsoid-shaped horizontal salt rock underground storage is taken as an example, and a single-cavern horizontal salt rock underground storage model with different diameter-to-height ratios is established by using FLAC3D software. The change law of vertical and horizontal displacements, volume loss rate, and plastic zone distribution of salt rock storage changing with the diameter-to-height ratio are studied, and the optimal diameter-to-height ratio is determined. And then the long-term operation process of the double-cavern horizontal salt rock underground storage under the optimal diameter-to-height ratio is simulated, and the optimal pillar width is obtained.

On g-Extra Conditional Diagnosability of Twisted Hypercubes under MM∗ Model

Connectivity and diagnosability are important parameters in measuring the reliability and fault-tolerance of an interconnection network [Formula: see text]. The [Formula: see text]-extra conditional faulty set [Formula: see text] is a faulty vertex set such that every component of [Formula: see text] has at least [Formula: see text] vertices. The [Formula: see text]-extra connectivity [Formula: see text] of a connected graph [Formula: see text] is the minimum cardinality of a [Formula: see text]-extra conditional faulty set [Formula: see text] of [Formula: see text] such that [Formula: see text] is disconnected. The [Formula: see text]-extra conditional diagnosability [Formula: see text] of a graph [Formula: see text] is the maximum value of [Formula: see text] such that [Formula: see text] is [Formula: see text]-extra conditionally [Formula: see text]-diagnosable. The [Formula: see text]-extra connectivity of [Formula: see text] is necessary for [Formula: see text]-extra diagnosability of [Formula: see text]. The [Formula: see text]-dimensional twisted hypercube [Formula: see text] is a new variant of hypercubes with asymptotically optimal diameter. In this paper, we first give the [Formula: see text]-extra connectivity of [Formula: see text] for [Formula: see text] and [Formula: see text]; and then obtain the [Formula: see text]-extra conditional diagnosability of [Formula: see text] for [Formula: see text] and [Formula: see text] under the MM[Formula: see text] model.

DETERMINATION OF OPTIMAL DIAMETER OF ADAPTIVE PROPULSOR OF MOBILE ROBOTICS COMPLEX

Using graphs of dependence of change of optimal diameters from change of ratio of weight coefficients, mass, geometric, soil characteristics, general equation of change of diameter of adaptive propulsor of mobile robotics complex is revealed.

OPTIMIZATION OF VESSELS SIZES FROM THE CONDITIONS OF THE MINIMUM HULL SURFACE AREA

The method of optimization of vessels sizes for the reasons of the minimum surface area of the hull is considered. The dependences of the optimal diameter, height and minimum surface area of the tank body on the volume are obtained.