I. Kozma

56294219000

Publications - 6

CT-Based Defect Analysis in Aluminium Rotor End Rings †

I. Zsoldos I. Kozma

Publication Name: Engineering Proceedings

Publication Date: 2024-01-01

Volume: 79

Issue: 1

Page Range: Unknown

Description:

The advantages of using cast aluminium rotors have been proven recently. However, discontinuities and porosities created during the casting of aluminium can cause problems during motor operation, such as eccentricity, losses, unwanted sounds, and false rotor fault indications. During the casting technology, care must be taken to ensure that there are as few cracks and porosities as possible in the volume and that their distribution is homogeneous. In this article, we present in detail the application of the modern CT-based methodology that has been spreading recently for the detection and analysis of discontinuities, voids, and porosities created during the casting of rotor end rings.

Open Access: Yes

DOI: 10.3390/engproc2024079093

CT-based tests and finite element simulation for failure analysis of syntactic foams

I. Zsoldos I. Kozma

Publication Name: Engineering Failure Analysis

Publication Date: 2019-10-01

Volume: 104

Issue: Unknown

Page Range: 371-378

Description:

A unique compression test was carried out on aluminium matrix syntactic foams combined with X-ray micro CT structure analysis, in order to obtain a full reconstruction of the failure process of syntactic foams. The compression test was interrupted in small compression steps and CT imaging was performed after each interruption. As a result of the reconstruction different regions of the failure process were defined. A characteristic shear plane was found as the typical deterioration place. A CAD model was generated from the CT-base reconstruction of the specimen and a finite element algorithm was run on the CAD model. It was computed from the mechanical stress distribution that the plane, having been fitted to the weakest points of the structure, is identical to the characteristic shear plane. As our results indicate, using a finite element analysis on a CT-based reconstructed model is one way to prognosticate the deterioration of a structure.

Open Access: Yes

DOI: 10.1016/j.engfailanal.2019.06.003

Displacement-based failure analysis of metal matrix syntactic foam

I. Zsoldos I. Kozma Dóra Harangozó H. Hargitai

Publication Name: Wit Transactions on Engineering Sciences

Publication Date: 2019-01-01

Volume: 124

Issue: Unknown

Page Range: 161-173

Description:

Metal matrix syntactic foams are being used more and more widely thanks to their relative density as well as their perfect energy-absorbing characteristics. Multiple studies concern the economical production of these materials – particularly, how energy absorption as a physical characteristic can be increased. Many studies examined the effects of material choice as well as cell size and wall thickness of reinforcing materials on compressive strength. However, there are only estimated models about descriptions concerning decaying processes of samples from different material composition and geometrical variation. In this study, we introduced an “in situ” examination in order to model the decaying process. We upsetted aluminium-ceramic composite foams cyclically. We reconstructed the geometry of the sample with microcomputed tomography (μCT) technology and digital image processing at certain specified points of the compression test. During the complete decaying process, the process was evaluated with volume change and number of broken hollow particles, as well as elementary particle displacements, orientation and sphericity of the reinforced material.

Open Access: Yes

DOI: 10.2495/MC190161

Failure analysis of aluminum - Ceramic composites

I. Fekete I. Zsoldos I. Kozma

Publication Name: Materials Science Forum

Publication Date: 2017-01-01

Volume: 885

Issue: Unknown

Page Range: 286-291

Description:

The increasingly widespread use of syntactic metal foams is due to their excellent energy absorbing characteristics. Several research groups deal with developing methods that can further improve this characteristic. Several literature analyses have been devoted to the effects of materials selection, cell size and wall thickness of the reinforcing element on the compression strength. In this work an in situ test necessary for the modeling of the failure process introduced. The aluminumceramic composite foams were cyclically upset. The geometry of the test specimen was reconstructed at a certain point of the compression test by μCT technology and digital image analysis. The failure process was characterized by volume change, by the number of broken shells and by the formation of shear plane as a function of the deformation.

Open Access: Yes

DOI: 10.4028/www.scientific.net/MSF.885.286

CT based analysis of reworked BGA devices

I. Fekete I. Kozma R. Csontos

Publication Name: 21st Imeko TC 4 International Symposium on Understanding the World Through Electrical and Electronic Measurement and 19th International Workshop on ADC Modelling and Testing

Publication Date: 2016-01-01

Volume: Unknown

Issue: Unknown

Page Range: 288-292

Description:

The widespread use of computed tomography in the electronic field allows for an extended range of measurements to be carried out. High integration devices can be tested easily with μCT, and provide large amount of data to characterize the technology parameters. This paper focuses on the inspection of BGA solder ball geometry and quantification of different properties of the solder arrays.

Open Access: Yes

DOI: DOI not available

Computer tomography based reconstruction of metal matrix syntactic foams

I. Zsoldos Sz Papp I. Kozma G. Dorogi

Publication Name: Periodica Polytechnica Mechanical Engineering

Publication Date: 2014-01-01

Volume: 58

Issue: 2

Page Range: 87-91

Description:

In order to create 3D (three-dimensional) models for finite element calculations it is necessary to reconstruct the structure of metal foam composites reinforced by hollow ceramic spheres. A new algorithm was developed for this reconstruction work. This algorithm is based on the investigation of sphericity of the shapes found on CT (computer tomograph) layer records. Using this algorithm a 3D CAD (computer aided design) model of acceptable precision can be constructed.

Open Access: Yes

DOI: 10.3311/PPme.7337