Houari, A.; Mokhtari, M.; Bouchikhi, A.S.; Polat, A.; Madani, K.

FGM (functionally graded materials) have experienced rapid expansion in recent years in several industrial fields. The analysis of their mechanical behavior by the finite element method requires the use of subroutines established under a FORTRAN compiler given the difficulty in implementing the type of behavior of the materials constituting the FGM. Our work aims to establish a program in MATLAB (UMM) making possible to introduce the behavior of the FGM by element in the mesh model of the structure, hence the advantage and reliability of graded the material in three dimensions for two or even three constituents of FGM and secondly, for different geometric designs. This technique is more sensitive to the mesh, hence the adaptation strategy of a driven mesh in order to improve the precision and the convergence of results under minimal computation time. The constitutive law of our model follows the von Mises equivalent stress flow theory with a hardening variable in incremental form. Moreover, to describe the elastic–plastic behavior of FGM, the model of TTO (Tamura-Tomota-Ozawa) was used for both methods that of UMAT in the form of a numerical algorithm and for our new method in the form of calculated values by the MATLAB code. The parameters used in the two calculation methods are taken from the results of stress–strain tests of the two materials; ceramic (TiB; Titanium mono biorde) and metal (Ti; Titanium). A comparison between the two methods has taken place in the form of load–displacement curves in order to present the capacities of our technique with respect to the usual UMAT technique. However, for damage, the use of the XFEM technique in our UMM method has shown its advantage in the separation of the structure after crack initiation. The crack path as well as its propagation speed under the effect of the volume fraction exponent of the FGM has been highlighted. The two models used in this study (UMM and UMAT) were validated on the one hand with analytics through the TTO model and on the other hand by the experimentation of a tensile test.

AtıfScopus17·WoS16·OpenAlex18

İncele

Polat, A.; Kaya, Y.; Bendine, K.; Özşahin, T.Ş.

In this study, continuous contact problem in the functionally graded (FG) layer loaded with two rigid flat blocks resting on the elastic semi-infinite plane was analyzed by the finite element method. The two-dimensional numerical model of the FG layer was made with the software added to the ANSYS program. This software can be adapted to all contact problem types by making minor changes. The accuracy check of the program was performed by comparing with the analytical solution of the problem by homogeneous layer and its solution by the finite element method. So, fast and practical solutions can be obtained by the developed finite element method on many applications such as; automotive, aviation and space industry applications. The comparisons made showed that the proposed solution gave good results at acceptable levels. In the problem, it was thought that all surfaces were frictionless. The external loads P and Q were transmitted to the FG layer via two flat rigid blocks. Normal stresses between the FG layer and the elastic plane, initial separation loads, initial separation distances and contact stresses under the blocks were investigated for various dimensionless quantities.

AtıfScopus14·WoS14·OpenAlex11

İncele

Kaya, Y.; Polat, A.; Bora, P.; Bendine, K.; Özşahin, T.ş.

The difficulty of producing functionally graded materials (FGM) and the fact that they are more expensive than homogeneous materials emerge as an industrial problem. The starting point of this study is to investigate alternative solution methods that will contribute to the mentioned problem. In parallel, the analysis of the contact problem for a layer, which is loaded by a rigid block and resting on the elastic half plane, is presented in this paper. Only the area under the block is considered as FGM, the other parts are considered homogeneous material, unlike the studies in the literature. There is no analytical solution for this study and it is compared with the solution which is completely functionally graded (FG) layer in the literature by using finite element method (FEM). Material properties of the FG layer are defined by the macro added to the ANSYS program. The analysis for the partial FG layer were compared with the completely FG layer analysis as figures and tables, and as a result it was predicted that partial FGM could be used for the static problems and may also be practical applications in the industry.

AtıfOpenAlex1·TR Dizin1

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