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Fault diagnosis of bearings is essential in manufacturing to increase quality. Traditionally, fault diagnosis of tapered roller element bearings is performed by signal processing methods, which handle the nonstationary behaviour of the signal. The wavelet transform is an efficient tool for analysing the vibration signal of the bearings because it can detect the sudden changes and transient impulses in the signal caused by faults in the bearing elements. In this article, manufacturing faults on the outer ring of tapered roller bearings due to the grinding process in manufacturing are investigated. Nine different real values wavelets (Symlet-2, Symlet-5, Symlet-8, db02, db06, db10, db14, Meyer, and Morlet) are compared according to the Energy-to-Shannon-Entropy ratio criteria, and which is efficient for detecting the manufacturing faults is determined. Finally, experiments are carried out on a test rig for determining the geometrical size of the manufacturing faults with all wavelets directly from the vibration signature the result of db02, Symlet-5, and Morlet wavelets are presented. When modelling the bearing structure as an under-damped second-order mass-spring-damper mechanical system, its unit impulse response function is compared to the wavelets on the basis of their Energy-to-Shannon-Entropy ratio to determine the fault size from the vibration signal. The proposed technique has been successfully implemented for measuring defect widths. The maximum deviation in result has been found to be 4.12 % for the defect width which was verified with image analysis methods using an optical microscope and contact measurement. Odkrivanje napak v izdelavi je ključnega pomena za izboljšanje kakovosti proizvodnje ležajev. Namen članka je analiza možnosti odkrivanja napak v izdelavi koničnih kotalnih ležajev iz signala vibracij ter ugotavljanje geometrijske velikosti napak na zunanjem obroču. Tradicionalne metode, kot je Fourierjeva transformacija, zaradi posebne narave signalov niso dovolj uspešne pri zaznavanju prehodnih impulzov. Konični kotalni ležaji so le redko predmet znanstvenih člankov, čeprav predstavljajo pomemben del avtomobilskih menjalnikov in sistemov prenosa moči. Večina znanstvenih člankov, ki se ukvarjajo z obrabo, se kljub pomenu te problematike ne posveča težavam pri izdelavi. V članku je zato predstavljena nova rešitev, ki bi jo bilo mogoče učinkovito uporabiti v industriji.

The development of an efficient procedure for 3d modeling and finite element simulation of metal foams is one of the greatest challenges for engineer researchers nowadays. Creating 3d CAD model is alone a demanding engineering task due to its extremely complex geometry, and the proper finite element analysis process is still in the center of the research. The increasingly widespread application of the metal foams, e.g. in vehicle and medical industry, requires this knowledge in the design phase. A closed-cell metal foam is studied using different analyzing methods where the aim is to collect information about the composition and geometry (structure) that is satisfactory for the later research. Using statistical methods microscopic, X-ray and surface analyzing studies on the specimens produced according to the concerning standard are evaluated. The main goal of this part of the project is to obtain structural information and to determine the homogeneity or the in-homogeneity property of the metal foam specimens taken from different locations.

In rubber products design finite element analysis is a widely used technique. In many cases, the pre-defined operating conditions can be achieved by changing the geometric dimensions of the product which is the well-known iterative design method. Using more than one design parameter the number of possible combinations will increase significantly. The application of Support Vector Machine (SVM) can handle the large number of data in a special way and helps to find the optimal design parameters. In this paper an optimization process of a rubber jounce is presented using nonlinear finite element analysis and SVM.

The rubber bumpers built into the air-spring structures of buses perform a number of critical tasks. Consequently, designing their shape requires considerable effort. This paper presents a novel solution for determining the required characteristics of axi-symmetric rubber parts, which can efficiently be used in practice. The procedure is based on the finite element method (FEM) and the support vector regression (SVR) model. A finite element code developed by the authors and based on a three-field functional is used for the rapid and appropriately accurate calculation of the characteristics of rubber bumpers. A rubber shape is evaluated via the work difference and the area between the desired and the actual load-displacement curves. The objective of shape optimization is to find the geometry where the work difference is under a specified limit. The tool of optimization is the SVR method, which provides the regression function for the work difference. The minimization process of the work-difference function leads to the optimum design parameters. The efficiency of the method is verified by numerical examples. Gumijasti blažilniki, vgrajeni v sisteme zračnega vzmetenja avtobusov, opravljajo vrsto pomembnih nalog, konstruiranje gumijastih blažilnikov pa je zato precej zahtevno. V članku je predstavljena nova, praktično uporabna rešitev za zagotavljanje zahtevane karakteristike gumijastih osnosimetričnih blažilnikov. Prava karakteristika podajanja pod obremenitvijo je osnovna zahteva pri snovanju gumijastih blažilnikov. Avtomobilska industrija mehkejšo ali tršo izvedbo gumijastih blažilnikov običajno zagotavlja s spremembo sestave gume. Cilj optimizacije je doseganje zahtevane karakteristike z geometrijsko obliko gumijastega blažilnika ob nespremenjenih lastnostih materiala. Namen raziskave je določanje vedenja gumijastih blažilnikov pri različnih delovnih pogojih. Gumijasti blažilniki se ne upravljajo aktivno, zato je zahtevano karakteristiko mogoče doseči z optimizacijo oblike.

This paper presents a novel solution for shape optimization of compressed rubber parts. The procedure is based on the finite element method (FEM). A special purpose FEM code written in FORTRAN has been developed for the analysis of nearly incompressible axi-symmetric rubber parts. Numerical stability of the code and sensitivity analysis of the FEM input parameters are investigated. The aim of the parameter optimization is to reduce the time consuming FEM computations for the optimization process. The objective of the optimization is to find the optimal shape of the investigated rubber parts with a specified load-displacement curve. A regression model is used to determine the connection between the input and output data calculated by the FEM.

In this paper a solution of a contact problem for large displacements and deformations are analyzed where a rubber bumper applied in air–spring. The nonlinear load-displacement curve is determined. A FEM code written in FORTRAN has been developed for the analysis of nearly incompressible axially symmetric rubber parts. The Hu Washizu type variational principle is formulated for the Mooney-Rivlin material model. Stability and sensitivity analyses are also investigated.

In rubber product design finite element analysis is widely used. The aim of this research is to choose the appropriate material models and to determine the related material parameters for finite element analysis of a rubber jounce. Rubber products can suffer from large deformation upon working conditions while behaving as a non-linearly elastic, isotropic and incompressible material. Hyperelastic material models accurately describe the observed material behaviour. Uniaxial compression test of rubber specimen has been performed to determine the stress-strain curve. Using test data and ANSYS for curve fitting process, the material constants for Mooney-Rivlin and Yeoh model have been established. Finite element analysis of the compression test has been made to validate the specified material constants. It can be stated that three term Yeoh model showed better agreement with the test data than the one term formula. Two term Mooney-Rivlin model showed good match with the measurement data, thereby it is also recommended for the future investigations of rubber jounce.