Simulation Analysis and Experimental Study of Piezoelectric Power Generation Device Based on Shape Memory Alloy Drive

In order to solve the problem of waste heat collection from energy consumption, a thermal energy generation device combining shape memory alloy and piezoelectric materials has been designed. The shape memory alloy is heated and deformed to drive the drive wheel continuously, and the impact wheel is deformed against the piezoelectric cantilever beam during the rotation of the drive wheel to generate electricity. In this paper, the impact force generated by the impact wheel and the output voltage of the piezoelectric cantilever beam during the rotation process are given. Finally, the experimental test shows that the larger the radius of the drive wheel, the lower the impact force of the wheel and the lower the output voltage of the piezoelectric cantilever beam; the larger the diameter of the shape memory alloy wire, the higher the impact force of the wheel and the higher the output voltage of the piezoelectric cantilever beam; the more teeth of the drive wheel, the higher the impact frequency of the piezoelectric cantilever beam and the higher the output voltage. The maximum output voltage of the thermoelectric converter is 14.2 V, when the drive wheel radius is 13 mm, the shape memory alloy wire diameter is 1 mm and the number of impact wheel teeth is 6. The new structural design provides a new structural model for waste heat recovery and thermal energy generation technology. The new structural design provides a new approach and idea for waste heat recovery and thermal energy generation technology.

Modernization of the construction of the crane traveling wheel

The article discusses the modernization of the running wheel due to the introduction of an elastic element. The structure, which consists of three layers, the outer ones of which consist of strong steel material, and the middle layer consists of low-strength lightweight aggregate, which can significantly reduce dynamic forces, vibrations and shocks, which increases the reliability of cargo transportation. Calculations have shown that the stress state of a wheel with an elastic insert is less than that of an old-design travel wheel. The decrease in force and elastic factors in the travel wheel, which has an elastic insert, is explained by the fact that the use of an elastic ring leads to an increase in the bending stiffness of the outer ring of the shell. The obtained solution to the problem of the strength of a three-layer structure makes it possible to determine the stresses in the shell depending not only on its geometric parameters, but also on the shear modulus of the filler, which improves the reliability of the design and operation of such structures. Theoretical studies of the stress state of a three-layer cylindrical structure, taking into account the shear energy of the filler, makes it possible to assess the strength of such a structure and give certain recommendations for its use. Experimental studies that were carried out on an operating overhead crane fully confirmed a very significant reduction in oscillatory processes in travel wheels. The level of vibration acceleration in the vertical direction on the modernized drive wheel is almost 3 times less than the level of vibration acceleration on the drive wheel at idle speed of a conventional design.

Numerical Modeling of Mine Hoist Disc Brake Temperature for Safer Operation

The sustainable exploitation of raw materials, with improved safety and increased productivity, is closely linked to the development of mechanical mining installations. Mine hoists are designed for the transport of material, equipment and personnel between the mine surface and the underground. The mine hoist braking system is of paramount importance in its safe operation. Thus, for both drum and disc brake systems, the temperature of the friction surfaces is important for ensuring efficient braking, as exceeding the temperature threshold causes a decrease in the braking capacity. In this paper we present a numerical calculation model for the temperature of the braking disc of a mine hoist in the case of emergency braking. A real-scale model was built, based on the cable drive wheel and disc brake system of a hoisting machine used in Romania. Real material characteristics were imposed for the brake discs, the cable drive wheel and the brake pads. The simulation was performed for decelerations of 3, 3.5, 4 and 4.5 m/s2. The analysis shows that regardless of the acceleration and time simulated, the disc temperature reaches its maximum after 1.35 s of emergency braking. This value does not exceed the 327 °C limit where, according to previous studies, the braking power starts to fade. It means that the emergency braking is safe for the acceleration and masses under consideration, in the case of the studied mine hoist.

DRAWING UP THE POWER BALANCE FOR THE DRIVING WHEEL OF THE CAR USING THE SPEED PLAN

The method of drawing up the power balance for the driving wheel of a car using the speed plan of individual points of the wheel is presented. The linear velocities of the characteristic points are determined by their components, taking into account three wheel radii – dynamic and two kinematic. The kinematic radii are represented by the rolling radius of the wheel in the free mode and the rolling radius of the wheel in the driving mode. As a result, the linear velocities are reduced to two components, depending on the kinematic radii and the angular velocity of the wheel. They allow you to determine all the components of the power balance of the drive wheel in combination with the acting longitudinal forces, reactions and moments.