Attila Schweighardt

57218530695

Publications - 6

A Preliminary Study on Laser Surface Texturing of Passenger Car Engine Piston Rings

András Lajos Nagy Attila Schweighardt Gabor Laki Gergely Kovács

Publication Name: Fme Transactions

Publication Date: 2025-01-01

Volume: 53

Issue: 2

Page Range: 252-259

Description:

Laser surface texturing offers a possible solution for reducing friction between sliding surfaces in engineering applications. Optimized surface topography can also contribute to reduced wear and elevated longevity by modifying the load and speed-dependent friction state in a system. This preliminaryexperimental study investigates the applicability of affordable fibre laser marking systems for microtexturing piston rings, in order to achieve a measurable reduction in friction under subsystem model conditions. A selection of textures are applied to chromium-coated cast iron piston rings. The resulting surface topographies are characterized through confocal microscopy and subjected to friction testing. A correlation analysis is conducted on surface topography parameters to identify key laser process parameters. Findings indicate an improvement in the range of 7–8% in terms of friction coefficient with appropriate texture size.

Open Access: Yes

DOI: 10.5937/fme2502252L

The effect of the preload determination process on dynamic mechanical properties

Dániel Feszty Balázs Vehovszky Attila Schweighardt

Publication Name: Journal of Physics Conference Series

Publication Date: 2023-01-01

Volume: 2677

Issue: 1

Page Range: Unknown

Description:

NVH simulation and experimental methods are getting more and more important because of the increased customer needs for reliability and comfort. In order to obtain appropriate NVH simulation results accurate material properties have to be provided as input parameters. In case of the dynamic mechanical property determination of acoustic viscoelastic foams the results may vary greatly depending on the measurement settings and the quality of the measurement. This study evaluates the effect of the preload determination process on dynamic mechanical properties and the repeatability of the dynamic compression tests. Finally, conclusions are drawn and suggestions are made for the settings.

Open Access: Yes

DOI: 10.1088/1742-6596/2677/1/012007

Investigation of frequency dependent mechanical properties of porous materials using dynamic mechanical analyzer and frequency-temperature superposition theory

Balázs Vehovszky Attila Schweighardt

Publication Name: Proceedings of Inter Noise 2021 2021 International Congress and Exposition of Noise Control Engineering

Publication Date: 2021-01-01

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

In acoustic design of engineering applications - such as in the acoustic analysis of passenger vehicles - poroelastic materials are of great importance. One of the most influencing properties in determining their noise-reduction potential is the storage modulus. The purpose of this study is to examine the frequency dependence of storage modulus of selected porous acoustic materials at least up to 1000 Hz. This is executed by using the combined use of dynamic mechanical analyzer and frequency-temperature superposition theory. All other methods for measuring the storage modulus fall short in determining frequency-dependence above 100 Hz: quasi-static mechanical analyzer is mostly used for determining an averaged constant value deduced from low-frequency measurements, while the usage of an electromagnetic shaker capable for high-frequency excitation may include effects of fluid motion inside the pores, thus significantly modifying the results. Frequency-temperature superposition enables to determine the storage modulus values in a wide frequency range, based on low-frequency measurements, where fluid-structure interaction is negligible. It was found that the modulus varied significantly up to and beyond 1000 Hz, and thus, acoustical characterization of these materials can be significantly improved using the proposed method. The work concludes with recommendations to improve the accuracy of the results.

Open Access: Yes

DOI: 10.3397/IN-2021-2859

NVH characterization of a ladder-like welded structure using finite element analysis and experimental method

Dániel Feszty Balázs Vehovszky Attila Schweighardt

Publication Name: Advances in Acoustics Noise and Vibration 2021 Proceedings of the 27th International Congress on Sound and Vibration Icsv 2021

Publication Date: 2021-01-01

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

In vehicle industry, considering a chassis, the evaluation of the experimental modal analysis is usually done up to 80 Hz, since the modal density is increasing with frequency. In addition, the deviation between the measurement and simulation is getting more significant at higher frequencies. The purpose of this study is to extend the usable test range and to improve the accuracy of the results both in case of measurement and FE (Finite Element) simulation. Present paper introduces the vibrational characterization of a ladder-like welded structure. This test case represents a simplified model of a vehicle's frame consisting of rod-like elements with high stiffness, connected to each other in welded junctions. Although such simulational and experimental modal analysis procedures are widely used in practice, results can significantly change according to the used method and the fine-tuning of parameters. For this reason, a further goal is to find the best measurement and simulation technique for the given structure. During the FE analysis different modelling solutions and element types were compared. In order to discover the effect of the manufacturing inaccuracies, the same measurements were performed on two distinct, but theoretically identical samples. The influence of the experimental setup (e.g. excitation and fixing method) and settings were investigated as well. Finally, FE simulation and experimental results are compared using Frequency Response Functions.

Open Access: Yes

DOI: DOI not available

Development of 1D and 3D acoustic simulation methods for transmission loss based on transfer matrix measurement results

Balázs Vehovszky Balázs Kuti Zoltán Gazdagh Attila Schweighardt Miklós Szendrő

Publication Name: Advances in Acoustics Noise and Vibration 2021 Proceedings of the 27th International Congress on Sound and Vibration Icsv 2021

Publication Date: 2021-01-01

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

During the acoustical characterization of a component of a building, machine or vehicle, the normal incidence sound transmission loss is a major factor. Transmission loss simulation is also crucial in designing intake or exhaust elements, such as reflective mufflers. However, there is not enough information in the open literature about the applicable frequency ranges of experimental and 1- and 3D simulation methods. Therefore, the main purpose of this paper is to evaluate the frequency limits of computational and experimental transmission loss analyses of various reflective mufflers. For the validation two in-house impedance tube test benches were designed and multiple measurement setups were investigated. The combination of the four-pole matrix and the two-load methods was used during the experimental part of the study. In order to obtain appropriate transfer function results, distinct setups were evaluated, such as a low-frequency sound source with bigger tube diameter and a high-frequency sound source with smaller tube diameter. The low-frequency setup is suitable for the investigation of the system in the range of 30-500 Hz. The high-frequency setup is capable of measuring from 300 Hz to 2000 Hz, which is the upper frequency limit of the range of interest. Consequently, the in-house system is suitable for measuring the transmission loss in the 30-2000 Hz frequency range. 1D simulations were performed using Ricardo Wave software and 3D simulations were carried out in the STAR-CCM+ software. The upper cutoff frequency of 1D simulation method was determined to be 1500 Hz according to the correlation with the measurements. The frequency range of simulation could be extended up to 2000 Hz by employing 3D simulation for transmission loss calculations. This paper gives insights into the transmission loss measurements with the in-house system and the correlation analysis with different simulation methods.

Open Access: Yes

DOI: DOI not available

Modal analysis of the tubular space frame of a formula student race car

Dániel Feszty Balázs Vehovszky Attila Schweighardt

Publication Name: Manufacturing Technology

Publication Date: 2020-08-06

Volume: 20

Issue: 1

Page Range: 84-91

Description:

This document presents the characterization of the dynamic mechanical properties of a racecar's frame. First, it introduces the applicability of modal analysis, then the modal analysis of a lightweight vehicle chassis will be detailed, which is the focal point of this paper. This analysis was performed to determine some of the modal parameters, in order to reduce the noise of the vehicle, the probability of a component failure and to improve the comfort. The simulation part of the applied analysis was based on dynamic FEM (Finite Element Method). The measurement part of it was based on measuring the FRFs (Frequency Response Functions), with the help of accelerometers fixed at the nodes of the frame. The excitation signals were provided by a shaker connected to the chassis. In order to provide good quality results, the processing and evaluation of the simulated and measured data has to be done properly, which is discussed in detail. However, one dominant factor of a modal analysis is to find the optimal measurement setup. For this reason, the details of the measurement setup will be included. Hence one of the goals was to improve the coherence curves of the FRFs. Thanks to the presented techniques, the coherence curves managed to be improved and the results of the simulation and the measurement were found to be in good agreement.

Open Access: Yes

DOI: 10.21062/mft.2020.013