FE analysis of crack problems in functionally graded materials under thermal stress

Berrahal, L.; Boulenouar, Abdelkader; Ferhat, Yazid Ait; Miloudi, A.; Naoum, H.

doi:10.1007/s12008-022-01179-3

Cited by 5 publications

(3 citation statements)

References 33 publications

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“…The tendency of metals to form cracks during grinding depends on metallurgical and structural heredity, which is determined by smelting methods and the degree of deoxidation, phase transformations in alloys, and modes of thermal, chemical-thermal treatment. Operations preceding the finish [6,7], [8,9]. At the same time, the parameters that take into account the dependence of the stress state on the structural components are a set of mechanical characteristics (К1С, КС, КISC, Кth) of fracture mechanics [10,11].…”

Section: Literature Overviewmentioning

confidence: 99%

“…The quality of the surface layer is formed under the influence of thermomechanical phenomena accompanying the final operations. Therefore, in works [1,2], [3,7], [8,9], [10], the thermal tension of diamond abrasive processing is used as the leading indicator of the physical and mechanical condition of the treated surfaces. Based on the models of temperature fields developed by them, the regularities of the formation of defects such as cautery and the technological possibilities of their elimination were studied depending on the thermophysical properties of the processed materials and the technological parameters of their processing.…”

Section: Literature Overviewmentioning

confidence: 99%

“…Modeling of the influence of initial piecewise homogeneity of materials being ground (coated parts) on thermomechanical processes is carried out by the method of discontinuous solutions [9,12]. They mean solutions that satisfy the equations of Fourier heat conduction and Lamé elasticity everywhere except at the boundaries of defects.…”

Section: General Provisionsmentioning

confidence: 99%

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An information model concept for a thermomechanical process in grinding

Usov,

Kunitsyn,

Zaychyk

2023

HAIT

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The purpose of the work is to present the concept of an information modelof the thermomechanical process in grinding of products from materials prone to defect formation due to the fact that their surface layer has hereditary defects of structural or technological origin.The products' strength and functionality depend on the inhomogeneity and defectiveness of the structure of the materials from which they are made. Such materials have many different micro defects formed in the surface layer of parts during the technological operations of their production. Reducing number of defectsin the finishing operations of these materials and increasing the operational properties of products made of these materials is an essential national and economical task, the solution of which leads to a significant saving of material resources, labour intensity and cost of manufacturing parts. The currently available information on the thermal processes of diamond abrasive processing is obtained on the assumption of the homogeneity of the materials being polished and needs to consider the presence of defects in the technological heredity of the products. The phenomenological approach in studying the causes of cracking of materials prone to this type of defect does not allow to revealthe mechanism of genesis and development of grinding cracks. The choice of the method of investigation of the mechanism of crack formation is based on micro-research related to inhomogeneities, which are formed in the surface layer of parts during previous technological operations. A mathematical model has been developed that describes thermomechanical processes in the surface layer during grinding of parts made of materials and alloys, taking into account their inhomogeneities, which affect the intensity of the formation of grinding cracks. Calculated dependences between the crack resistance criterion and the main controlling technological parameters were obtained. According to the known characteristics of hereditary defects, the limit values of thermomechanical criteria, which ensure the necessary quality of the surfaces of the processed products, are determined. Based on the obtained criterion ratios, an algorithm for selecting technological possibilities for defect-free processing of products from materials prone to loss of quality of the surface layer of parts was built. A decision support system has been developed to increase the efficiency of the finishing process management.

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Section: Literature Overviewmentioning

confidence: 99%

Section: Literature Overviewmentioning

confidence: 99%

Section: General Provisionsmentioning

confidence: 99%

See 1 more Smart Citation

An information model concept for a thermomechanical process in grinding

Usov,

Kunitsyn,

Zaychyk

2023

HAIT

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Thermal Stress Analysis for Functionally Graded Plates with Modulus Gradation, Part II

Baytak,

Tosun,

Ipek

et al. 2024

Exp Mech

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Background The gradation of thermal expansion coefficient was analyzed in the earlier study. The analytical formulation derived here, which is quite different, should be validated to understand the thermal stress distribution in a laminated composite and functionally graded material. Besides this solution, a validated numerical model can also be used to optimize the material gradation of plates in terms of sustainability. Objective To validate the analytical formulation derived here, an experimental model is presented to understand the thermal stress concentration for functionally graded and laminated composite plates. A numerical model is also validated to extend to understand the effects of the number of layers, the thickness of a layer, the gradation function, the ratio of elastic moduli, and the coating. Methods The experimental problems in the production of the experimental models with layers of different elastic moduli are discussed here. In the experimental analysis, a three-dimensional photoelastic stress analysis of two- and four-layer composite plate was used to mechanically model the thermal expansion. The analytical solution for the thermal stress in a free plate was derived by the strain suppression method based on the principle of superposition. The numerical models were analyzed using finite element software. The step variation in the experiment was used as a reference point for a continuous or multi-layer (> 2) step variation of material coefficients in the models. Results The variation of stress concentration is shown for various cases of laminated and continuous gradations of elastic modulus. The four-layer experimental model provides the difference in thermal stress distribution as a result of a layered coating. The validated analytical and numerical models provide reasonable results. An empirical formula to optimize the material gradation in terms of elastic modulus is derived. Conclusions The experimental model can be used to analyze thermal stress in functionally graded materials. The gradations of the material in the plate or the coating of the plates can be optimized by the validated analytical and numerical models. The empirical formula can be used to determine the elastic modulus of the coating to minimize the stress concentration.

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