Applied Mechanics and Materials Vol. 732

Abstract: Substitute of the traditional materials with new plastic-based and composite materials is a trend in today's automotive industry. Mechanical properties of the composite parts are highly influenced by the composite production (material of fibers and their distribution, type and density of a filler). Knowledge of the specific composite material mechanical properties is necessary for CAD modeling and FEM calculations during the assembly design. These mechanical properties can be obtained by creating a composite structure in FEM software. However, the real composite may be different from the ideal FEM model (due to inaccuracies in its manufacture). Therefore, it is highly advisable to verify the modeling results by measuring of the real composite material properties. Identification and verification of the composite tube mechanical properties used in the hybrid car tailgate are described in this paper.

Abstract: This paper deals with the progressive failure analysis of sandwich composite beam loaded with transversely low-velocity impact. A user defined material model was used for modeling of the non-linear orthotropic elastic behavior of composite skin. The non-linear behavior of foam core was modeled using Low-Density Foam material model. The numerical model was validated using performed experiment and the results in terms of deflection and contact force time dependencies are mutually compared.

Abstract: There are many ways to model and to analyze discrete event systems. In general these systems lead to a non-linear characteristic equation description in linear algebra. This paper presents an analytical method for solving the characteristic equation of higher order, which arise when solving ordinary differential equations of motion of rigid body systems with 2 ≤ p° ≤ 10 degrees of freedom. The objective of this work was to express the characteristic equation in the form of product quadratic polynomial, from which the modal components could be found. To validate the model, the modal parameters extraction technique – Ibrahim Time Domain (ITD) – was used to extract modal parameters from artificial data developed in MATLAB environment. The extracted modal components were compared to those obtained from the analytical model.

Abstract: Vibratory conveyors are used especially within serial productions for the transport of diverse materials and parts for assembling. The desired oscillating movement is accomplished by electromagnetic exciting forces. The exciting force of this dynamic system actuates between the carrying element and the inertial mass. The inertial mass is fixed to the ground by an elastic constraint using a relatively stiff rubber spring. This elastic constraint ensures the conveyor’s stability and defines its position towards the assembly line, but does not meet relevant effective vibration isolation demands. One possible solution would be a vibratory conveyor air suspension as is being introduced below.

Abstract: This article deals with the reasons for gear failure - Flank breakage on tooth of spur gears with helical and straight involute gears. Gear flank breakage can be observed on edge zone-hardened gears. The creation of flank and tooth breakage and FEM simulation of flank breakage on tooth are described in this article. In the article are also described and short photo documentation from real load tests on mechanically closed stand for testing of gearing with helical gears and different nitrided depth.

Abstract: Sound effect derives a pair of highly loaded machinery parts-motion screw and nut. Loaded pair is used in non-standard environments of high voltage electrical equipment in electrical substations. The non-standard environment is seen in the movement of this pair immersed in transformer oil deeply below the surface. Transformer oil has no good mechanical lubricating properties because it does not contain sulfur. Loaded pair cannot be lubricated, because there would be oil contamination and deterioration of its electro-insulating properties. The causes were sought in the structure of the machine, frame stiffness, mechanical strength machine and used materials. The aim of the research with help experimental and numerical study was to define the cause and eliminate sound effect coming from the device.

Abstract: Fibres, cables and wires can play an important role in design of many machines. One of the most interesting applications is replacement of chosen rigid elements of a manipulator or a mechanism by fibres. Dynamic behaviour of fibres in simplified mechanical systems was investigated. In the first step the computational investigation of a fibre dynamic behaviour in the system of an inverted pendulum attached to two fibres and driven by them was performed. Then experiments and computer simulations with two simple laboratory mechanical systems followed. The first system consisted of a weight moving on an inclined plane and of one fibre, the second one contained a drive and a pulley in addition to it. The results of experimental measurements serve for tuning the computational models. The simulation aim is to create a phenomenological model of a fibre.

Abstract: The contribution solves the effect of the construction, operation and excitation asymmetry of the simple spatial model. The model can be used for simulation of the vibration of the vehicles (road and rail). The solution was performed by experiments and numerical methods. The mathematical model was developed to reliable describe the experimental simple spatial model. The model was verified by experimental results.

Abstract: Published paper summarizes development of unique testing stand for experimental testing of railway vehicle gearboxes under dynamic impact and torque load. There is presented a description of design of main parts. Paper also previews the process of implementation and first run-in tests including figures from tuning process and a picture of final design.

Abstract: This paper introduces a description of the partial section of the complex agricultural trailer development. The paper is focused on performed experimental measurements, specifically on the dynamic operational testing. For this purpose, a testing polygon was designed and experimental measurements were used to collect data about load spectra of selected components of the developed trailer. Used methodology of the testing may be used on similar cases with welded steel constructions.