scholarly journals A functionally graded material model for the transmural stress distribution of the aortic valve leaflet

2017 ◽  
Vol 54 ◽  
pp. 88-95 ◽  
Author(s):  
Bruno V. Rego ◽  
Michael S. Sacks
Keyword(s):  
Aortic Valve ◽  
Stress Distribution ◽  
Functionally Graded Material ◽  
Material Model ◽  
Functionally Graded ◽  
Valve Leaflet ◽  
Aortic Valve Leaflet ◽  
Graded Material

Finite Element Analysis of Human Tibia Modeled as a Functionally Graded Material

2019 ◽  
Vol 2 (3) ◽  
Author(s):  
Ashish Tiwari ◽  
Pankaj Wahi ◽  
Niraj Sinha
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Functionally Graded Material ◽  
Material Properties ◽  
Functionally Graded ◽  
Element Analysis ◽  
Cross Sectional ◽  
Human Tibia ◽  
Graded Material

Human tibia, the second largest bone in human body, is made of complex biological material having inhomogeneity and anisotropy in such a manner that makes it a functionally graded material. While analyses of human tibia assuming it to be made of different material regions have been attempted in past, functionally graded nature of the bone in the mechanical analysis has not been considered. This study highlights the importance of functional grading of material properties in capturing the correct stress distribution from the finite element analysis (FEA) of human tibia under static loading. Isotropic and orthotropic material properties of different regions of human tibia have been graded functionally in three different manners and assigned to the tibia model. The nonfunctionally graded and functionally graded models of tibia have been compared with each other. It was observed that the model in which functional grading was not performed, uneven distribution and unrealistic spikes of stresses occurred at the interfaces of different material regions. On the contrary, the models with functional grading were free from this potential artifact. Hence, our analysis suggests that functional grading is essential for predicting the actual distribution of stresses in the entire bone, which is important for biomechanical analysis. We find that orthotropic nature of the bone tends to increase the maximum von Mises stress in the entire tibia, while inclusion of cross-sectional inhomogeneity typically increases the stresses across normal cross section. Accordingly, our analysis suggests that both orthotropy as well as cross-sectional inhomogeneity should be included to correctly capture the stress distribution in the bone.

Multiscale Modelling Method for Chosen Functionally Graded Material

2013 ◽  
Vol 199 ◽  
pp. 593-598 ◽  
Author(s):  
Danuta Miedzińska ◽  
Robert Panowicz ◽  
Przemysław Jóźwicki
Keyword(s):  
Functionally Graded Material ◽  
Hardness Test ◽  
Material Model ◽  
Steel Sample ◽  
Homogenization Method ◽  
Functionally Graded ◽  
Test Method ◽  
Homogenization Theory ◽  
Good Correspondence ◽  
Graded Material

The paper deals with the numerical and experimental analyses of functionally graded material structures which are represented by a surface layer of the steel sample hardened during the laser treatment process. A functionally graded parameter of the researched structure was assumed as the hardness value experimentally measured with the use of a Vickers hardness test method. The microstructure of the tested layer was also analyzed for the Vickers test verification. Two homogenization methods were used for the purpose of layer substitute properties for numerical calculations. The first one was to divide the FGM domain into a number of layers in the direction of material gradation and then apply a numerical homogenization method within each layer. The resulting material model describes the FGM as a composite of homogeneous layers. The second method was based on the Mori-Tanaka homogenization theory and was carried out with the use of Digimat software, which is the nonlinear multi-scale materials and structures modelling platform. Both methods were compared and showed good correspondence.

Elastoplastic Analysis of a Functionally Graded Material Beam Subjected to Uniformly Distributed Load

2019 ◽  
Vol 36 (1) ◽  
pp. 73-85
Author(s):  
L. J. Xue ◽  
X. Y. Bian ◽  
J. J. Feng ◽  
J. N. Liu
Keyword(s):  
Stress Distribution ◽  
Functionally Graded Material ◽  
Functionally Graded ◽  
Average Stress ◽  
Elastoplastic Material ◽  
Elastoplastic Behavior ◽  
Distributed Load ◽  
Uniformly Distributed Load ◽  
Graded Material ◽  
Fgm Beam

ABSTRACTThe elastoplastic behavior of a Functionally Graded Material (FGM) simply supported beam consisting of elastic material A and elastoplastic material B under uniformly distributed load is investigated. A power function is used to describe the volume fractions of the constituent materials, and the average stress of the FGM beam is obtained by using the averaging method. This method can avoid the assumption of the varying properties of the whole material, and can consider the different Possion’s ratios of the different constituent materials. What’s more, only the elastoplastic material B in the FGM beam will yield, and the yield function is determined by the stress of material B only, rather than the average stress of the whole material. The method used in this work is more closer to the real material than the method by assuming the variation of the whole properties of FGM. The theoretical results show a good agreement with the finite element results, which indicates that the method provided in this work is valid. With this method, the variation of the elastic and plastic areas, the stress distribution on the cross section, variation of the curvature and neutral layer, and the residual stress distribution of the FGM beam are discussed through numerical results. This work can provide a new way for the design and in-depth investigation of FGM material.

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