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 order to create 3D (three-dimensional) Keywords syntactic foam · CT based reconstruction IntroductionThe metallic foams have a special class which satisfies the definition of particle reinforced metal matrix composites also. These are the metal matrix syntactic foams. The metal matrix syntactic foams have numerous perspective applications as covers, hulls, castings, or in automotive and electromechanical industry sectors because of their high energy absorbing and damping capability. In these porous materials the porosity is ensured by incorporating ceramic hollow microspheres [1]. The microspheres are commercially available and they contain mainly various oxide ceramics [2,3].The most important properties of the metal matrix syntactic foams are the compressive strength and the absorbed energy [4][5][6][7][8][9][10].The quality and chemical composition of the microspheres influence many properties of the syntactic foams. And they have also strong influence during the production of the syntactic foams. The foams are usually produced by mixing technique and gravitational casting or by pressure infiltration [11][12][13].Because of the strong effect of the quality of the microspheres (diameter of ~ 0.1-3 mm) on the mechanical and other properties of the foams the investigation of the structure of the syntactic foams is very important. In order to create real 3D models from the syntactic foams the CT-based reconstruction methods can be applicable. CT-based reconstruction methods are used successfully in many different materials research fields as for example porous polymeric materials (foams) [14], open celled and closed-cell metallic foams [15][16]. Recently the X-ray computed microtomography has been applied on porous fuel cell materials [17] and soil samples [18]. The history, the production, the geometrical, mechanical, thermal properties the dynamical behaviour and the fatigue processes of hollow spheres were studied in details [19].Structural characterisation and morphology of metal foams were studied with models reconstructed from CT images [20]. In order to apply the CT-images for the reconstruction of the syntactic foams a new algorithm is shown in this work.

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Abstract-In order to create 3D models used in finite element analysis, a reconstruction of the structure of metal foam composites reinforced with ceramic spherical shells is necessary. A new algorithm has been developed for reconstruction. The input of the algorithm consists of CT layer images which were created at the Szechenyi Istvan University, Györ, Hungary. The CT images were analyzed by the new algorithm. The algorithm seeks the contours of the spherical shells by gradually increasing the radii, also in CT images. A suitably accurate 3D CAD model can be created with algorithm.

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 aluminum-ceramic 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.