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EN
This article presents the basic airfoil model with two degrees of freedom - the semi-rigid model, where its forced vibrations were considered, and the exciting force is the aerodynamic force, including its periodic changes, that is, gusts. Since the phenomenological model under study has a coupled form, its versions after decoupling are presented, which has an impact on the results of the final research. The airfoil model presented in this way was shown from the application side in the system of a simple energy harvester based on a deformable beam with piezoelectric elements. The result of the simulation tests is a preliminary analysis of the possibility of using the airfoil as a vibration generator for the energy harvesting system. Along with the application of the mechanical part, a numerical simulation of the electrical part was also implemented, related to the transformation of the voltage generated by piezoelectric elements into a constant voltage signal with a connected receiver with power consumption similar to the Atmega microcontroller with battery charging.
EN
In the structure of crane bumpers, there is a need to join various types of steel. Usually, low-alloy steel structures are used for this purpose, which can be represented by S355J2 steel. The tensile strength of S355J2 low-alloy steel is slightly below 600 MPa, and the tensile strength of S355J2 steel is at the high level of 200 J at ambient temperature. The impact strength of this steel in negative temperatures is also good at over 47 J at -60 °C, so it meets the 6th class of impact toughness. Welding structures, after classic gas metal arc welding (GMAW) processes, meet only the second impact toughness class. An improved GMAW process was used by micro-jet cooling application to raise the mechanical properties of the joints. The microstructure and main properties of the joints were carefully analyzed. The influence of using the new suggested welding process on the various properties of the welds is presented (UTS - ultimate tensile strength, YS - yield strength, Poisson ratio, elongation, Young’s modulus). Then, the effects of tests for use in crane bumper construction were checked by using a hybrid finite element method (FEM) analysis.
EN
The paper shows the results of researching the rollers used in belt conveyors working in a hard coal mine. Rollers should be characterized by low rotation resistance, which results in low power consumption of the propulsion unit. The tests conducted aimed to assess the technical condition of the new C-type rollers after several years of operation in a hard coal mine. The research was carried out from the new approach to the standard issues of roll testing and verification in a hard coal mine. Laboratory tests were combined with testing the entire belt conveyor in terms of power demand. The research was carried out for 3 years and it was monitored how the dynamic resistance of the working rollers changed and how this translates into the power demand consumed by the belt conveyor in a hard coal mine. The aim of the research was a new approach to the research of rollers used in conveyors operating in a mine.
EN
This article presents research carried out using physical data from the experimental construction of an overhead crane. This article aims to determine the dynamic behaviour of the cart-pendulum system when the hoisting mechanism hits the new bumper design at the end of the girder support structure with selected speed and bumper material to the length of the wire rope. This research shows the influence of the horizontal speed of the hoisting mechanism on the bumper force during a collision with a standard buffer and its modifications. The presented model can be the basis for modelling more complex cases, and its assumed role (i.e. the ability to determine the angle of deflection of the rope during an impact) has been confirmed and is possible to use in a specific case of an overhead crane on an industrial scale. Preliminary analysis of the construction of the bumper considered reveals its positive features, aiming, among other goals, to reduce the acceleration and force acting on the crane cart in emergency situations.
EN
This article compares flexible couplings of the spider-type insert, and the tiretype insert. The influences of the volume and hardness of the elastomeric connector on the characteristics of this type of coupling, as well as the course of the change of the stiffness coefficient as a result of changes in the operating temperature, are presented. In drive systems, flexible couplings undergo very frequent changes within a wide range of operating temperatures, which causes a change in the dynamic parameters of the flexible couplings during operation.
EN
The article proposes a phenomenological model of a passenger car. The model includes the biomechanical model of human bodies in the sitting position of Muksian and Nash acting as passengers, while the driver’s weight has been reduced to the concentrated weight of the loading seat. The research carried out in this study consisted of passing the vehicle through a transverse obstacle along the so-called speed bump. Vehicle passes through the threshold at three different speeds: 10km/h, 20km/h, and 30km/h. The purpose of the conducted experiments was to initially estimate the values of accelerations acting especially on the passenger at selected driving speeds. On the basis of conducted tests, it was possible to verify the numerical model of the vehicle overcoming the obstacle on the road. This approach allows the use of the proposed model to verify the forces and accelerations affecting the passenger, specified before any selected specific biomechanical model of the human person, for example, a model of pregnant women in this configuration allows us to estimate the forces and accelerations acting on the embryo while overcoming some obstacles on the road.
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