Development of Modelling Methods for Materials to be Used as Bone Substitutes

2007 ◽  
Vol 361-363 ◽  
pp. 903-906 ◽  
Author(s):  
R. Gabbrielli ◽  
I.G. Turner ◽  
Chris R. Bowen
Keyword(s):  
Mechanical Strength ◽  
Volume Fraction ◽  
Bone Substitutes ◽  
Gradient Material ◽  
Periodic Surfaces ◽  
Triply Periodic ◽  
Functional Gradient Material ◽  
Spatial Periodicity ◽  
Bearing Materials ◽  
Modelling Methods

The demand in the medical industry for load bearing materials is ever increasing. The techniques currently used for the manufacture of such materials are not optimized in terms of porosity and mechanical strength. This study adopts a microstructural shape design approach to the production of open porous materials, which utilizes spatial periodicity as a simple way to generate the models. A set of triply periodic surfaces expressed via trigonometric functions in the implicit form are presented. A geometric description of the topology of the microstructure is necessary when macroscopic properties such as mechanical strength, stiffness and isotropy are required to be optimised for a given value of volume fraction. A distinction between the families of structures produced is made on the basis of topology. The models generated have been used successfully to manufacture both a range of structures with different volume fractions of pores and samples of functional gradient material using rapid prototyping.

scholarly journals ON THE LOSS OF STABILITY OF A TWO-LAYERED PLATE MADE OF A FUNCTIONAL-GRADIENT MATERIAL WITH A NON-UNIFORM FIELD OF PRE-STRESSES

2019 ◽  
Vol 81 (4) ◽  
pp. 513-520
Author(s):  
V.V. Eremeev
Keyword(s):  
Constitutive Relation ◽  
Linear Instability ◽  
Functionally Graded ◽  
Initial Stresses ◽  
Gradient Material ◽  
Internal Stresses ◽  
Uniform Field ◽  
Loss Of Stability ◽  
Material Inhomogeneity ◽  
Functional Gradient Material

In the framework of three-dimensional nonlinear elasticity we consider linear instability of a composite plate made of functionally graded material and having initial stresses. The plae consists of two layers which were obtained as a result of flattening of an annual sector of an elastic cylinder. This deformation results in appearance of internal stresses. Thus, the plate becomes initially stressed. The initial stresses depend on the thickness coordinate, so we get inhomogeneous stress field. We have two types of inhomogeneities, the first is the inhomogeneity of the initial stresses whereas the second is the material inhomogeneity.We use the incompressible neo-Hookean material model as a constitutive relation. Despite of relatively simple form this model describes properly severe deformations of some rubber-like materials. For incompressible materials the flattening constitutes one of the so-called universal deformations, that is such deformation which is independent on the choice of constitutive relation. The material inhomogeneity is described through a dependence of the shear modulus on the thickness coordinate. Such inhomogeneity could be related to the manufacturing of the material or to further treatment. The stability was analysed using the linearization approach. We superimpose infinitesimal deformations on the finite initial one. The linearized boundary-value problem was derived and its nontrivial solutions were obtained. The solution was obtained in series of trigonometric functions. This helps to automatically satisfy a part of boundary conditions. We consider the influence of the inhomogeneity and initial stresses. We show that the initial stresses may significantly change critical deformations. For example, the loss of stability is possible due to initial stresses only.

Design of variable thickness triply periodic surfaces for additive manufacturing

2019 ◽  
Vol 4 (3) ◽  
pp. 281-290 ◽  
Author(s):  
Gianpaolo Savio ◽  
Roberto Meneghello ◽  
Gianmaria Concheri
Keyword(s):  
Additive Manufacturing ◽  
Variable Thickness ◽  
Periodic Surfaces ◽  
Triply Periodic

scholarly journals Buckling of a composite bar made of a functional-gradient material with an inhomogeneous pre-stress field

2018 ◽  
Vol 226 ◽  
pp. 01014
Author(s):  
Vadim V. Eremeev ◽  
Denis V. Ivashchenko
Keyword(s):  
Stress Field ◽  
Circular Cylinder ◽  
Nonlinear Elasticity ◽  
Linear Instability ◽  
Initial Stresses ◽  
Gradient Material ◽  
Material Inhomogeneity ◽  
Functional Gradient ◽  
Functional Gradient Material ◽  
Graded Material

Within the 3D nonlinear elasticity we discuss the linear instability of a composite bar made of a functially graded material and having initial stresses. The bar consists of two layers which are inflated for a annular wedge of a circular cylinder. We present the linearized boundary0value problem and obtain its non-trivial solutions. The influence of the material inhomogeneity and the initial stresses are discussed.

Tensile Properties of Epoxy Matrix Reinforced with Fique Fabric

2020 ◽  
Vol 1012 ◽  
pp. 14-19
Author(s):  
Michelle Souza Oliveira ◽  
Fabio da Costa Garcia Filho ◽  
Fernanda Santos da Luz ◽  
Artur Camposo Pereira ◽  
Luana Cristyne da Cruz Demosthenes ◽  
...  
Keyword(s):  
Mechanical Strength ◽  
Polymer Composites ◽  
Natural Fiber ◽  
Volume Fraction ◽  
Fiber Reinforced Polymer ◽  
Epoxy Composites ◽  
Synthetic Fiber ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Fiber Reinforced Polymer Composites

Composite materials are being extensively studied for ballistic armor. Their main advantage is connected to the possibility of deeply reducing weight and costs by maintaining high performances in terms of strength and security. Epoxy composites are reinforced with natural fibers which are replacing other synthetic reinforcement materials. Composites are prepared using polymers as matrix material because of ease of production with different reinforcements. The mechanical strength of the natural fiber reinforced polymer composites has been compared with synthetic fiber reinforced polymer composites and it is found that for achieving equivalent mechanical strength of the material, the volume fraction of the natural fiber should be much higher than synthetic fiber. This work being an experimental study on untreated “as received” fique fabric-reinforced epoxy composites, to demonstrate the potential of this renewable source of natural fiber for use in a number of applications.

Microstructure and Properties of Spark Plasma Sintering AlN/BN Ceramics

2006 ◽  
Vol 313 ◽  
pp. 105-108 ◽  
Author(s):  
Lian Meng Zhang ◽  
Mei Juan Li ◽  
Qiang Shen ◽  
T. Li ◽  
M.Q. Yu
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Mechanical Strength ◽  
Spark Plasma Sintering ◽  
Volume Fraction ◽  
Sintering Temperature ◽  
Composite Ceramics ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Full Densification

Aluminum nitride-boron nitride (AlN/BN) composite ceramics were prepared by spark plasma sintering (SPS). The sintering behaviors of AlN/BN composites with 5~15% volume fraction of BN were studied. The influences of BN content, as well as the sintering temperature on the density, microstructure, mechanical strength, thermal conductivity and machinability of the composites were also investigated. The results showed that the full densification of AlN/BN composite ceramics could be realized by SPS technique at the temperature no higher than 1800°C for 3 minutes. The thermal conductivity of AlN/BN composites is in the range of 66~79W/mK, and AlN/BN composites can be cut or drilled by carbides or even steel tools when BN content is 15% volume fraction. The mechanical strength of AlN/BN composites is about 330MPa and is not remarkably affected by the addition of BN. The improvement of mechanical properties of AlN/BN composite ceramics is due to the fine and homogenous microstructure developed in the SPS process.

scholarly journals New Hybrid Bioactive Composites for Bone Substitution

Processes ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 335 ◽  
Author(s):  
Anna Ślósarczyk ◽  
Joanna Czechowska ◽  
Ewelina Cichoń ◽  
Aneta Zima
Keyword(s):  
Phase Composition ◽  
Physicochemical Properties ◽  
Mechanical Strength ◽  
Organic Materials ◽  
Setting Time ◽  
Bone Substitutes ◽  
Bone Implant ◽  
Load Bearing ◽  
Implant Materials ◽  
Bioactive Composites

Recently, intensive efforts have been undertaken to find new, superior biomaterial solutions in the field of hybrid inorganic–organic materials. In our studies, biomicroconcretes containing hydroxyapatite (HAp)–chitosan (CTS) granules dispersed in an α tricalcium phospahate (αTCP) matrix were investigated. The influence of CTS content and the size of granules on the physicochemical properties of final bone implant materials (setting time, porosity, mechanical strength, and phase composition) were evaluated. The obtained materials were found to be promising bone substitutes for use in non-load bearing applications.

scholarly journals Three-Dimensional Free Vibration Analysis of Thermally Loaded FGM Sandwich Plates

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2377 ◽  
Author(s):  
Burlayenko ◽  
Sadowski ◽  
Dimitrova
Keyword(s):  
Finite Element ◽  
High Efficiency ◽  
Volume Fraction ◽  
Plate Thickness ◽  
Three Dimensional ◽  
Free Vibration Analysis ◽  
Free Vibrations ◽  
Gradient Material ◽  
Benchmark Problems ◽  
Sandwich Plates

Using the finite element code ABAQUS and the user-defined material utilities UMAT and UMATHT, a solid brick graded finite element is developed for three-dimensional (3D) modeling of free vibrations of thermally loaded functionally gradient material (FGM) sandwich plates. The mechanical and thermal material properties of the FGM sandwich plates are assumed to vary gradually in the thickness direction, according to a power-law fraction distribution. Benchmark problems are firstly considered to assess the performance and accuracy of the proposed 3D graded finite element. Comparisons with the reference solutions revealed high efficiency and good capabilities of the developed element for the 3D simulations of thermomechanical and vibration responses of FGM sandwich plates. Some parametric studies are carried out for the frequency analysis by varying the volume fraction profile and the temperature distribution across the plate thickness.

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