David Sipos

57219552070

Publications - 5

Comparison of Clustering-Based Virtual SEA Subsystem Generation Models

Dániel Feszty David Sipos

Publication Name: Journal of Theoretical and Computational Acoustics

Publication Date: 2023-09-01

Volume: 31

Issue: 3

Page Range: Unknown

Description:

Building a valid Statistical Energy Analysis (SEA) model is far from straightforward in real life applications because it has to comply with certain requirements. Since intuition-based SEA subsystems do not always entirely meet these, more advanced methods such as clustering techniques have been proposed for model building. This paper focuses on the comparison of different clustering techniques from SEA model validity point of view in the case of a simplified car body model. Besides the compliance with the SEA theory, each obtained model is compared to a reference finite element simulation to assess its accuracy.

Open Access: Yes

DOI: 10.1142/S2591728523500081

Validation of finite element connection modeling by comparison of experimental and virtual power injection methods

Dániel Feszty Marcell Treszkai David Sipos

Publication Name: Journal of Vibroengineering

Publication Date: 2023-01-01

Volume: 25

Issue: 1

Page Range: 209-225

Description:

There are several ways to obtain the matrix of damping loss factors and coupling loss factors for Statistical Energy Analysis. The most recent approach is Virtual SEA, where the Power Injection Method is performed virtually on a finite element model. In order to validate this approach, the most common connection types are investigated in this paper through an L-junction of two coupled steel plates. Virtual SEA and experimental Power Injection Method results are compared in a bent, line welded, superglued and spotwelded variants. The respective finite element connection representation is also validated during the comparison. It was found that with the correct simulation setup, Virtual SEA provides good agreement with the experimental results. In case of the spotwelded variants, further investigations were necessary regarding the parameters of the connection. The influence of these parameters was evaluated and the greatest source of deviations in the results is found.

Open Access: Yes

DOI: 10.21595/jve.2022.22754

Optimization of damping pad distribution on body-in-white car structure

Dániel Feszty Marcell Treszkai David Sipos

Publication Name: Journal of Vibroengineering

Publication Date: 2022-01-01

Volume: 24

Issue: 2

Page Range: 386-393

Description:

Structure-born noise is one of the most important contributors to the interior noise in a vehicle cabin. This can be effectively reduced by placing damping pads with special material properties along the chassis and on the large, radiating panels. This paper proposes a new methodology for the optimization of placing these pads as a part of a full vehicle acoustic simulation in Actran Virtual SEA. With this new strategy, it was possible to reduce the among of damping pads on a real car structure by 33 % while keeping the same acoustic performance. This was validated by investigating the mean velocity of the floor panel in two load cases and compared to the original damping pad layout to the optimized one.

Open Access: Yes

DOI: 10.21595/jve.2021.22158

Welding distortion generated uncertainties in the vibrational behavior of a ladder-like structure

Dániel Feszty Marcell Treszkai David Sipos

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:

Recent developments in acoustic simulation methods allowed engineers to assess the vibroacoustic behavior of various type of structures within a virtual environment, thus allowing the replacement of prototype-based development with simulations. However, there are some factors, that cannot be considered in simulations in advance. In the present study, the effect of the distortions generated due to welding on a ladder-like structure equipped with flat plates was investigated. The measured acceleration frequency response functions were compared to finite element simulation results. The measured responses differed significantly from the simulation, even in the low frequency ranges, where the global modes were not expected to be altered or vanished. Investigation of the simulated results revealed that the additional modes were related to the vibration of the plates, which were assumed to be flat, instead of considering the warping caused by the welding process. After measuring the approximate deformation of the plates, an updated simulation model was made, introducing an approximate curvature in them. The results obtained with the updated simulation model performed much better in the low frequency range as well as in the third octave-averaged frequency bands up 1200 Hz. The sensitivity of the warping was also systematically evaluated.

Open Access: Yes

DOI: 10.3397/IN-2021-2844

Extended Solution of a Trimmed Vehicle Finite Element Model in the Mid-Frequency Range

Dániel Feszty Jonathan Jacqmot Antoine Guellec Markus Brandstetter David Sipos

Publication Name: SAE Technical Papers

Publication Date: 2020-09-30

Volume: Unknown

Issue: 2020

Page Range: Unknown

Description:

The acoustic trim components play an essential role in Noise, Vibration and Harshness (NVH) behavior by reducing both the structure borne and airborne noise transmission while participating to the absorption inside the car and the damping of the structure. Over the past years, the interest for numerical solutions to predict the noise including trim effects in mid-frequency range has grown, leading to the development of dedicated CAE tools. Finite Element (FE) models are an established method to analyze NVH problems. FE analysis is a robust and versatile approach that can be used for a large number of applications, like noise prediction inside and outside the vehicle due to different sources or pass-by noise simulation. Typically, results feature high quality correlations. However, future challenges, such as electric motorized vehicles, with changes of the motor noise spectrum, will require an extension of the existing approaches. In this paper, the vibro-acoustic frequency response of an existing MSC Nastran FE model is extended using the Actran Statistical Energy Analysis (SEA) approach, Virtual SEA. In Virtual SEA, the necessary information required to build the SEA system is extracted from the FE models. The fluid-structure Coupling Loss Factors (CLF) are computed through the Statistical modal Energy distribution Analysis (SmEdA) method. This method is a suitable candidate to account for acoustic trim effects based on analytical approach. The case studied consists of a trimmed body car model transfer function calculation. The result of the case study is an extensive correlation study containing measured and simulated transfer functions in low and mid-frequency range. Simulation results are derived from two approaches, FE method and Virtual SEA method.

Open Access: Yes

DOI: 10.4271/2020-01-1549