RU206856U1 - A device for determining the deformation rheological characteristics of a ski snow track - Google Patents

Abstract

The utility model relates to the field of testing in engineering surveys in elite sports, in particular, to a device for determining the deformation rheological characteristics of the snow cover of a ski track in competition conditions. This data is used to determine and select skis that correspond in their parameters to the deformation rheological characteristics of the ski track. and a block that registers and processes the registered data and contains a power supply unit, characterized in that the stamp is made in the form of a ball, in the inner cavity of which a means for registering movements is installed, while the means for registering movements is made in the form of an acceleration sensor, and the block that registers and processes data, made in the form of an integrator of acceleration data. The technical result achieved by the claimed solution is to increase the speed and accuracy of determining the deformation characteristics of a snow ski track, the numerical value of the combination of elastic and elm their properties of a snow track, as well as in simplifying the design, reducing the dimensions and weight of the device, increasing mobility, increasing the speed of loading the die in accordance with the specific conditions of skiing.

Description

The utility model relates to the field of testing in engineering surveys in elite sports, in particular, to a device for determining the deformation characteristics of a snow cover in a competition environment. These data are used to determine and select skis that correspond in their parameters to the deformation rheological characteristics of the ski track.

State of the art.

A number of devices are known for studying the deformation characteristics of soils or snow, called penetrometers. In particular, the invention is known ("Snow strength penetrometer)) / U.S. Patent No. 5,831,161, G01N 3/42, 33/18, publ. 03.11.1998), intended for testing the snow cover during the construction of snow roads, runways, structures on the snow surface. The surface of the snow is loaded with stamps of various configurations through the rod using an electric motor. The experiments carried out make it possible to determine the modulus of elasticity, the angle of internal friction and the coefficient of compaction of the snow.

The advantages of this device include high accuracy of data recording due to the use of electronic sensors.

The disadvantages of this device and penetrometers include the high technical complexity of the mechanism, which consists of a large number of parts and connections. These devices are large and heavy. Time-consuming to set up and set up before taking measurements. Moreover, the shape of the stamps is specially designed for use in transport and technological engineering and does not provide sufficient accuracy in fixing the data necessary to construct the deformation characteristics of snow in specific skiing conditions.

Also known is a device for determining the rheological properties of a snow cover ("Device for determining the rheological properties of a snow cover." RF patent 2396539, G01N 3/00, publ. 08/10/2010.).

The device contains a rigid stamp mounted on a frame, mounted on a vertical rod, a rod drive, a means for registering its vertical displacements, and an immersion device.

The device consists of a lever with a support, on one side of which a rigid stamp with an adjustable rod drive is mounted on a hinge by means of a screw pair along the length of the rods, and on the other side a counterweight is suspended. At the ends of the lever, two rollers are fixed on top, through which a rope is thrown, connected by the ends on both sides with loading weights, which are, for example, a trolley with weights. An electric motor is also installed on the support, through the shaft of which a rope is thrown in the form of a movable loop. Thus, the rollers, the rope and the electric motor together constitute a mechanism for moving the loading loads.

The lever is fixed through the support post on a frame with four outriggers, on which a stop is additionally located, fixing the lever with a stamp in its original position, when pressure from the side of the stamp is not transmitted to the snow cover, as well as a recorder of vertical deformation of the snow cover, which is equipped with a tape recorder, consisting of a motor and a tape on a rotating drum, a movable recorder, which are mounted on a slide with guides, on the one hand, connected to an elastic element returning to the initial position, and on the other, with a movable part of the lever through an inextensible thread and a system of guide rollers.

The advantages of this device and method are as follows: Registration of experimental data is carried out in automatic mode, which ensures high measurement accuracy.

The disadvantages of this device include very specific loading conditions and the shape of the stamp, corresponding to the process of interaction of the mover of transport and technological machines with the snow bed. In skiing of the highest achievements, the conditions of deformation of a snow track are significantly distinguished by a high speed of application of loads.

In addition, the disadvantages include the technical complexity of the mechanism caused by the presence of a lever system that converts the horizontal movement of the load into the vertical movement of the stamp, the need to use additional balancing weights, the presence of a complex system of blocks that provides the transfer of torque from the drive motor to the moving weight.

The closest to the claimed device can be considered a device for determining the coefficients of rigidity and hardness of the snow cover ("Device for determining the hardness and hardness of the snow cover" RF Patent 173978, G01N 3/42, publ. 28.12.2016), selected as a prototype.

In a device containing a rigid stamp mounted on a frame, mounted on a vertical rod, a rod drive, a means for registering its vertical displacements and loads, a loading device, a vertical rod drive made in the form of a screw-nut transmission, and the frame is made in the form of a tripod with three telescopic supports, while the vertical rod with the guide is located in the center of the frame, the means for registering vertical movements of the rod is made in the form of a displacement sensor installed on the rod guide, and the means for registering the load is in the form of a dynamometer built into the rod, while the outputs of the displacement sensor and the dynamometer are connected to the input device that registers and processes the registered data. The registration of the value of the loading force is provided by a dynamometer, the value of the vertical deformation of the snow through the displacement of the stamp is provided by a displacement sensor.

The advantages of this device are:

- the ability to register not only the values of the vertical deformation of the snow, but also the magnitude of the loading force;

- expanding the range of sizes and shapes of used stamps.

The disadvantages of the device include:

- large dimensions, heavy weight of the device;

- a lot of time to prepare the device for operation;

- the speed of loading the punch is limited by a narrow range of low speeds (the speed of movement of the rod, which changes by varying the number of revolutions of the electric motor).

The interaction of skis with a snow track differs from the conditions of interaction with snow of a propulsion device of transport and technological machines.

To clarify these differences, FIG. 3 shows the diagrams of the pressure of skis on a snow track obtained on a laboratory bench (patent for a useful model of the Russian Federation No. 108616).

Here, the arrow shows the direction of ski sliding, and the blue and red plots show the length of the slip zone and the shape of the ski pressure on the snow track on the downhill and uphill. The size and speed of loading of the snow track depends on the length of the slip zone and on the speed of skiing.

Most scientists studying the physical and mechanical properties of snow note that snow belongs to the category of elastic-viscous-plastic materials (Anfilofiev B.A. Investigation of the rheological properties of snow cover. / B.A. Anfilofiev, V.K. Lokhin / Proceedings Novosibirsk Institute of Railway Transport. - Novosibirsk, 1972. - Issue 141). Thus, snow is characterized by elastic properties when light loads are applied for a fairly short time. Under these conditions, the deformations are small and reversible when the applied stresses are removed, the structure of the snow is not disturbed. For plastic flow, it is required that a certain threshold stress value is reached, after which it begins.

The distinction between liquids and solids is not sharp and has a kinetic (relaxation) character. With an increase in the strain rate, the elastic stresses do not have time to relax; therefore, the total resistance increases.

Accordingly, two types of bodies, extreme in their deformation behavior, are determined - an elastic body, when there is no energy dissipation during deformation; and a liquid incapable of storing deformation energy.

The deformation of the snow track is not described by any of these extreme schemes. Therefore, the snow track is characterized by various combinations of elastic and viscous properties.

The ski slopes are distinguished by their long length and a wide variety of snow conditions on different sections of the route. Therefore, before the competition, you need to move mobile along the track and take measurements of the deformation characteristics of the snow in several characteristic sections of the track. The known devices have a large mass, large overall dimensions and require a significant amount of time to prepare for measurements.

These disadvantages are eliminated by the proposed solution.

The essence of the technical solution.

The objective of the claimed solution is to create the most compact, easy-to-use device for promptly determining the deformation rheological characteristics of a snow ski track, namely, the numerical value of the combination of elastic and viscous properties, with the possibility of using high loading rates corresponding to loading rates in skiing.

The technical result achieved by the claimed solution consists in increasing the speed and accuracy of determining the deformation characteristics of the snow ski track, the numerical value of the combination of elastic and viscous properties of the snow track, as well as in simplifying the design, reducing the size and weight of the device, increasing mobility, increasing the speed of loading the stamp in according to the specific conditions of skiing.

This technical result is achieved by the fact that a device is used for determining the deformation rheological characteristics of a ski snow track, containing a rigid stamp, a means for recording movements installed on the stamp, connected by means of a data transmission unit with a data storage unit and a unit that records and processes the registered data and contains a power supply unit , characterized in that the stamp is made in the form of a ball, in the inner cavity of which a means for registering movements is installed, while the means for registering movements is made in the form of an acceleration sensor, and the unit that registers and processes data is made in the form of an integrator of acceleration data.

Brief description of the drawings.

FIG. 1 is a general view of the device.

FIG. 2 - device during testing.

FIG. 3 - diagram of the pressure of the ski on a snow track.

FIG. 4 is a diagram of the development of deformation of a rigid snow track when it is deformed by a punch in the form of a ball at a loading speed of 1.4 m / s.

FIG. 5 is a diagram of the development of deformation of a soft snow track when it is deformed by a punch in the form of a ball at a loading speed of 1.4 m / s.

FIG. 6 is a diagram of the development of deformation of a rigid snow track when it is deformed by a punch in the form of a ball at a loading speed of 3.13 m / s.

FIG. 7 is a diagram of the development of deformation of a soft snow track when it is deformed by a punch in the form of a ball at a loading speed of 3.13 m / s.

Detailed description of the technical solution.

A device for determining the deformation rheological characteristics of a ski snow track, containing a rigid stamp, a means for registering movements installed on the stamp, connected by means of a data transmission means with a data storage unit and a unit that records and processes recorded data and contains a power supply, characterized in that the stamp is made in in the form of a ball, in the inner cavity of which a means for registering movements is installed, while the means for registering movements is made in the form of an acceleration sensor, and the unit that registers and processes data is made in the form of an integrator of acceleration data.

The device contains (Fig. 1): a rigid stamp 1 in the form of a ball, in the inner cavity of the ball 1 there is a means for registering movements, a data transmission means 2 made in the form of a wired connection, a device 3 that records and processes data, containing a power supply unit and made in the form of an integrator of acceleration data and a datalogger 4 for storing the received data.

For registration, processing, integration and visualization of the obtained data, a smartphone or PC can also be used.

The device works as follows.

A ball-shaped stamp 1. (for example, with a diameter of 54 mm and a mass of 250 g) is thrown from a certain height (for example, 0.1 m) onto a snow track. A movement recording device (not shown) installed in the inner cavity of the ball 1, made, for example, in the form of an accelerometer sensor, registers the acceleration of the ball and, using the data transmission means 2, made in the form of a wired connection, transmits data of instantaneous accelerations with a sampling rate, for example , 1.5-2.5 kHz, to device 3, which records and processes data, made in the form of an integrator of acceleration data, from which the processed data is transmitted to the datalogger 4. The data stored on the datalogger are processed by a special program on the PC. It is possible to directly transmit data of instantaneous accelerations from the accelerometer via wireless communication, for example, WI-FI or Bluetooth, to a smartphone or PC, with data processing by a special program that integrates and visualizes the movement of stamp 1 in time, as well as obtaining the numerical value of the integral displacement of the ball when deforming a snow track.

A snow track can have different viscoelastic characteristics. In ideal conditions, there can be an elastic snow track, when practically no energy dissipation occurs during deformation from the impact of the ball 1. In this case, all the impact energy is spent on the ball upward rebound. And there may be a viscous snow track that is not capable of storing deformation energy. Here all the impact energy is converted into heat energy. Ball 1 does not bounce after hitting a snow track.

But in real conditions, a snow track is a combination of viscoelastic characteristics. The criterion for evaluating the viscoelastic characteristics of a snow track can be the numerical value of the integral of the displacements of the ball 1.

By integrating the data of the instantaneous acceleration of the ball twice, we obtain graphs of the ball's displacement during deformation of the snow track and the numerical value of the integral of displacements.

In the diagrams in FIG. 4 to FIG. 7, the falling branch of the graph characterizes both the viscous and elastic characteristics of the snow track. The more gently sloping, extended in time, the line of penetration of the ball into the snow track, the more viscous the snow track. The deeper the ball 1 deforms the snow track, the less elastic properties of the track. The ascending branch of the graph characterizes the elastic properties of the snow track. The steeper the ball bounce line in time and the higher the ball bounces, the greater the elastic properties of the track.

The rheological characteristics of a snow track significantly depend on the loading rate. Skiing on a snow track is characterized by a wide range of speeds and the use of skis with different lengths of slip zones. The ski loading speeds of the snow slope have a wide range. The loading rate table is shown above.

Therefore, tests of the deformational viscoelastic properties of a snow track must be carried out at different loading rates, changing the height of the ball dropping, for example, 0.1 m; 0.2 m; 0.3 m; 05 m; 1.0 m.

Thus, by analyzing the graph of the ball's deformation of the snow track in time, we can numerically estimate the ratio of the viscous and elastic characteristics of the snow track at different loading rates of the snow track.

The value of the integral displacement of the ball during deformation of the snow track serves as a criterion for assessing its viscoelastic characteristics. The higher the numerical value of this criterion, the higher the elastic properties of the snow track. Lower values of the criterion indicate more viscous characteristics of the track.

Depending on the deformation rheological characteristics of the snow track in competition conditions, the appropriate skis are selected. For example, for the integral displacement values of the ball shown in FIG. 4 and FIG. 6, with high elasticity of the track (0.086; 2.0), skis with shorter sliding zones (5-15 cm) are chosen. Such skis have high loading speeds on a snow track and less deformation of the track when sliding under these conditions.

For low integral displacement values shown in FIG. 5 and FIG. 7, with high viscosity (-1.5; -3.42) skis with longer sliding zones (20-50 cm) are chosen. Such skis have lower loading speeds of the snow track during sliding and less deformation of the track under these conditions.

Thus, it is obvious to a person skilled in the art that the technical result achieved by the claimed solution consists in increasing the speed and accuracy of determining the deformation characteristics of a snow ski track, the numerical value of the combination of elastic and viscous properties of a snow track, as well as in simplifying the design, reducing the dimensions and device weight, increased mobility, increased die loading speed in accordance with specific skiing conditions.

Claims (2)

1. A device for determining the deformation rheological characteristics of a ski snow track, containing a rigid stamp and a means for registering movements installed on the stamp, characterized in that the stamp is made in the form of a ball, in the inner cavity of which a means for registering movements is installed, made in the form of an acceleration sensor, and the stamp is configured to transfer data to a data storage unit and an acceleration data integrator. 2. A device for determining the deformation rheological characteristics of a ski snow track according to claim 1, characterized in that wireless data transmission between functional parts of the device is possible.

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