Applied Mechanics and Materials Vol. 827

Abstract: Torsional characteristics of the gearboxes are important for kinematic and dynamic behaviour of the whole drive train, especially the resonances. Measured values are used as an input for further dynamic calculations. The measurement of the torsional stiffness and backlash is carried out. For this purpose the incremental rotary sensors and magnetic sensor of position are used. The results shown the behaviour of the torsional stiffness of the gearbox during loading. Furthermore the backlash of the gearbox is measured.

Abstract: The paper deals with mode separation process in experimental modal analysis. The main role in this process plays a technique known as Enhanced Frequency Response Function (EFRF), which allows separate the different modes of a structure. The results of the separation are responses of isolated systems with one degree of freedom by means of which complex poles can be estimated with greater accuracy. The paper describes the basic principle of EFRF technique and also presents its application in experimental modal analysis.

Abstract: When is the hydropulser running, is a source of broad-band vibrations. Removing these unfavourable influences, which act negatively on environment and especially on human beings, is by an elastic support possible. Rubber or air springs are inserted between the frame of the hydropulser and the floor. Under these conditions, the transmission of vibration transferred to the floor declines according to values of natural frequencies. In this paper are discussed two possibilities of base plate (base) support. Especially using of air springs shows high efficiency of vibration insulation springing base

Abstract: Nowadays composite frames can be used, for its specific properties, in many fields of industry. Lightweight composite frames can be significant structural components in some transportations, flights and military applications. The main problem is how to use automatic applications for winding filaments of the carbon fibres on a closed spatial shaped core of product frames, that has been still doing by the hand manufacturing. For automatic production could be used unique prototype of robotic technology, which allows winding of the carbon fibres on closed shape into the core of a frame. The biggest problem of the clamping device, used for the closed frames, are their vibrations and resonance caused due to the rotary motions. The vibrations and resonance negatively affect the process of carbon fibres winding. Experimental measurements were carried out to determine the acceleration on individual arms of the clamping device, which reaches to 2.5±0.6 g. Minimizing of the vibration was performed by a hyperelastic elements which reduce vibrations to 0.4±0.15g.

Abstract: The important part of the validation and certification of the new product are vibration and shock testing of mechanical, electrical and electronic equipment components that are mounted on rail vehicles. The hydraulic shaker is possible to use as the vibration and shock exciter to simulate the effect of the environment to the specimen. It is necessary to fulfil the prescribe condition of the level of mechanical vibration and the acceleration peak of the shock test signals. The specific hydraulic motor produced by INOVA is designed for the specific vibration test and the aim is to use it also for the shock tests. The control algorithm uses two iteration methods in time and frequency domain and their use depends on test prescription.

Abstract: The Ring-Core method is a semi-destructive method for residual stress determination inside materials. The evaluation of residual stresses using Ring-Core method requires complex analysis of the geometric parameters. This work deals with the uniformly distributed residual stress components through the material thickness.

Abstract: Non-destructive methods for detection and measurement of residual stresses (RS) have been increasingly used in the last few years. The paper outlines the capability of Barkhausen noise analysis (BNA) for evaluation of real structure changes and RS on cross-section of welds due to welding of ferromagnetic plates compared with X-ray diffraction (XRD). The purpose of this study is to evaluate the RS distribution of specimens joined using by high power diode laser and metal active gas (MAG) welding that can be used for quantitative analysis of macro and micro level RS separately. The principal advantages of BNA over XRD as a tool for RS analysis and real structure characterisation are that it is mobile, faster with more facile carrying out and hence BNA is frequently used for continuous monitoring of RS in industrial processes.

Abstract: The method for residual stress measurement using through the hole drilling and investigation of the residual stresses relief with the help of incremental layers removing is presented. Drilling the rosette-hole from the opposite side – the inverse layers removing – have to be used for evaluation of residual stress near the back side of the object wall in cases when this surface is inaccessible for any hole-drilling instrument. The strain gauge rosette is installed on the opposite side of the drilled wall and a new mechanical task of incremental layers removal must be solved. The calibration constants for residual stress evaluation of HBM RY21 type rosette for this case were derived using numerical modeling by FEA and its experimental verification.

Abstract: The paper deals with an assessment of blade tip movements based on precise time measurement known under abbreviation BTT - Blade Tip Timing. In addition to the common way of BTT data processing, a new Residual Fatigue Lives of Blades system (RFLB) proceeds further up to estimation of blade damages by processing output files generated by BTT systems.

Abstract: Monitoring of residual stresses in components can be useful in predicting damage incidences caused by workload over lifetime of components. Non-destructive measuring and evaluation of residual stresses and chemical properties of stainless steel sample and its possibility to affect functional properties of the material by using the X-ray diffraction has some advantages. Measured sample or part does not require special preparation or destruction and so it is capable to operate after measuring. This method also determines orientation of residual stress, so it is possible to identify absolute values of shear and normal stress with high accuracy.