Modeling Relations between Processing, Microstructure and Mechanical Properties of Porous Bioceramics

2006 ◽  
Vol 15-17 ◽  
pp. 519-524
Author(s):  
Franck Tancret ◽  
Jean Michel Bouler
Keyword(s):  
Mechanical Properties ◽  
Fracture Stress ◽  
Biphasic Calcium Phosphate ◽  
Bending Strength ◽  
Bone Substitutes ◽  
Mechanical Tests ◽  
The Other ◽  
The Matrix ◽  
The One ◽  
Porous Bioceramics

Biphasic calcium phosphate (BCP) bioceramics, for use as resorbable bone substitutes, containing both isolated macropores and interconnected micropores, have been fabricated by sintering, using naphtalen particles as a porogen to produce macropores. The resulting ceramics contain ~ 45% macropores and various amounts of microporosity. Mechanical properties (compression and bending strength, toughness and hardness) have been measured and modeled by combining two approaches, at two different scales: the one describes the mechanical properties of a partly sintered stacking of grains, supposed to account for the interconnected microporosity, the other one holds in the case of closed and isolated macropores within a continuous matrix. The material is then represented as a quasi-continuous matrix containing macropores, the matrix being itself microporous. The model also considers that fracture always initiates on a macropore, which allows to set a correspondence between fracture toughness and fracture stress equations. The mechanical tests performed on the sintered ceramics tend to validate the modeling approach.

Validation of an Analytical Model Describing Mechanical Properties of Porous BCP Ceramics

2007 ◽  
Vol 361-363 ◽  
pp. 15-18
Author(s):  
François Pecqueux ◽  
Nathalie Payraudeau ◽  
Franck Tancret ◽  
Jean Michel Bouler
Keyword(s):  
Mechanical Properties ◽  
Biphasic Calcium Phosphate ◽  
Bone Substitutes ◽  
Mechanical Tests ◽  
Cold Isostatic Pressing ◽  
Bending Tests ◽  
Three Point Bending ◽  
Conventional Sintering ◽  
Critical Flaw ◽  
Modelling Approach

Macroporous biphasic calcium phosphate bioceramics, for use as bone substitutes, have been fabricated by cold isostatic pressing and conventional sintering, using naphthalene particles as a porogen to produce macropores. The resulting ceramics, composite materials made of hydroxyapatite and β-tricalcium phosphate containing various macroporosities and microporosities, have been submitted to compression and three-point bending tests. The mechanical tests performed on the sintered ceramics tend to validate the modelling approach and its hypothesis, i.e. the material can be considered as a microporous matrix containing isolated macropores, and the critical flaw is a macropore.

Fabrication and Mechanical Properties of Dense/Porous β-Tricalcium Phosphate Bioceramics

2007 ◽  
Vol 330-332 ◽  
pp. 907-910
Author(s):  
Fa Ming Zhang ◽  
Jiang Chang ◽  
Jian Xi Lu ◽  
Kai Li Lin
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Exponential Growth ◽  
Weight Bearing ◽  
Area Ratio ◽  
Sectional Area ◽  
Cross Sectional ◽  
The Matrix ◽  
Porous Bioceramics

Attempt to increase the mechanical properties of porous bioceramics, a dense/porous structured β-TCP bioceramics that mimic the characteristics of nature bone were fabricated. Experimental results show that the dense/porous structured β-TCP bioceramics demonstrated excellent mechanical properties with compressive strength up to 74 MPa and elastic modulus up to 960 MPa, which could be tailored by the dense/porous cross-sectional area ratio obeying the rule of exponential growth. The interface between the dense and porous bioceramics is connected compactly and tightly with some micropores distributed in the matrix of both porous and dense counterparts. The dense/porous structure of β-TCP bioceramics may provide an effective way to increase the mechanical properties of porous bioceramics for bone regeneration at weight bearing sites.

scholarly journals Mechanical and Erosion Behaviour of Ti47Al-3W/TI2ALC Composites by Reactive Arc-Melting

2003 ◽  
Vol 12 (4) ◽  
pp. 096369350301200
Author(s):  
Janakarajan Ramkumar ◽  
Atsushi Kakitsuji ◽  
S.K. Malhotra ◽  
R. Krishnamurthy ◽  
H. Mabuchi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tial Alloy ◽  
Bending Strength ◽  
Erosion Resistance ◽  
Arc Melting ◽  
Erosion Behaviour ◽  
Melting Technique ◽  
Fine Precipitate ◽  
The Matrix ◽  
Superior Mechanical Properties

Ti-50Al alloy and Ti-47Al-3W alloy and its composites have been prepared by reactive arc melting technique using elemental powders. Composites have been reinforced using 3.5, 10 and 18 vol% of Ti2AlC in the matrix of TiAl with and without addition of W and C. By the addition of tungsten and carbon to TiAl alloy, we have produced composites that are reinforced randomly by reacted rod like Ti2AlC particles with fine precipitate of Ti2AlC particles and B2 particles. Compared to Ti-50Al alloys, the Ti-47Al-3W alloy and its composites have superior mechanical properties like bending strength, hardness, fracture toughness and erosion. Ti-47Al-3W/3.5 vol% Ti2AlC has excellent erosion resistance because of the dispersion of fine Ti2AlC and B2 particles in the matrix.

Sulfonated Polystyrene Ionomers Neutralized with Mixtures of Various Cations Studied by Dynamic Mechanical and Small-Angle X-Ray Scattering Techniques

2003 ◽  
Vol 778 ◽  
Author(s):  
Ho Seung Jeon ◽  
Ju-Myung Song ◽  
Joon-Seop Kim
Keyword(s):  
Glass Transition ◽  
Dynamic Mechanical Properties ◽  
The Other ◽  
Transition Temperatures ◽  
Glass Transition Temperatures ◽  
Dynamic Mechanical ◽  
The Matrix ◽  
Cluster Phase ◽  
The One ◽  
Zinc Cations

AbstractThe effects of the addition of mixed cations, i.e. Na+/Cs+, Ba2+/Cs+, and Ba2+/Zn2+, to the acid form sulfonated styrene copolymers on their dynamic mechanical properties and morphology were investigated. It was found that the matrix glass transition temperatures did not change with the ratio of the one cation to the other. As expected, however, the ratio of one cation to the other in the mixed cations affected cluster glass transition temperatures significantly. It was also found that the activation energies for the glass transitions for the matrix phase remained constant, while those for the cluster phase changed with the ratio of the two cations. In addition, the position of the SAXS peak was found to be affected by the type of cations. From the results obtained above, the decrease in the cluster Tg with increasing the amount of cesium and zinc cations in Na/Cs, Ba/ Cs, and Ba/Zn mixtures, were explained on the basis of the considerations of the size, charge, and type of cations, which alter the degree of clustering as well as ion-hopping mechanism.

Spectral statistics of orthogonal and symplectic ensembles

2018 ◽  
Author(s):  
Greg W. Anderson
Keyword(s):  
Orthogonal Polynomials ◽  
Fundamental Theorem ◽  
The Other ◽  
Classical Orthogonal Polynomials ◽  
The Matrix ◽  
Spectral Statistics ◽  
Orthogonal And Symplectic Ensembles ◽  
The One ◽  
Gap Probabilities ◽  
Matrix Kernels

This article describes a direct approach for computing scalar and matrix kernels, respectively for the unitary ensembles on the one hand and the orthogonal and symplectic ensembles on the other hand, leading to correlation functions and gap probabilities. In the classical orthogonal polynomials (Hermite, Laguerre, and Jacobi), the matrix kernels for the orthogonal and symplectic ensemble are expressed in terms of the scalar kernel for the unitary case, using the relation between the classical orthogonal polynomials going with the unitary ensembles and the skew-orthogonal polynomials going with the orthogonal and symplectic ensembles. The article states the fundamental theorem relating the orthonormal and skew-orthonormal polynomials that enter into the Christoffel-Darboux kernels

A contrastive analysis of absolute constructions in French, German and Norwegian

2010 ◽  
Vol 33 (2) ◽  
pp. 208-223 ◽  
Author(s):  
Marianne Hobæk Haff
Keyword(s):  
The Other ◽  
General Question ◽  
Contrastive Analysis ◽  
The Matrix ◽  
The Subject ◽  
Similarities And Differences ◽  
The Absolute ◽  
The One ◽  
Germanic Languages ◽  
Matrix Subject

This paper is an exploration of similarities and differences concerning absolute constructions in French, German and Norwegian. In the first part, I have examined a more general question raised by these constructions: the connections between these types of absolute constructions and the matrix subject. I have shown that the means by which the absolute constructions are related to the subject can be morphosyntactic, semantic and pragmatic. The second part contains a purely contrastive analysis. Two issues have been examined: on the one hand, the absolute constructions and their congruent and non-congruent correspondences, on the other, the use of determiners. Essentially, French is different from the two Germanic languages, but similarities also exist between French and German, which are the center of a European Sprachbund.

Influence of Injection Conditions on the Mechanical Property of MWCNTs/ PC Nanocomposites

2014 ◽  
Vol 983 ◽  
pp. 94-98 ◽  
Author(s):  
Li Jun Wang ◽  
Jian Hui Qiu ◽  
Eiichi Sakai
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Mechanical Property ◽  
Bending Strength ◽  
Surface Hardness ◽  
Interfacial Interaction ◽  
Multiwalled Carbon ◽  
The Matrix ◽  
The Impact ◽  
Scanning Electron

The melting mixing was applied in the preparation of Multiwalled carbon nanotubes/Polycarbonate (MWCNTs/PC) nanocomposites. MWCNTs/PC nanocomposites with different MWCNTs contents were prepared under different injection conditions. The mechanical property of nanocomposites was comparatively investigated. The results demonstrated that: the tensile property of the nanocomposites was slightly improved by MWCNTs content increasing; but as the MWCNTs contents went on to increase to 10wt%, the tensile strength and bending strength were obviously decreased about 35% and 47%, respectively, but the impact strength and hardness were increased. The center hardness of MWCNTs/PC nanocomposites was greater than the surface hardness. Besides, the changes on the mechanical properties of the nanocomposites were studies by changing the injection conditions. By Scanning Electron Microscopy (SEM) observation, the microstructure and morphology of nanocomposites were analyzed, revealing that the center of the nanocomposite distributed more MWNTs, and the injection conditions would affect the MWNTs’ dispersion in the matrix and the interfacial interaction between MWCNTs and PC.

Effect of Preparation Process on Bending Modulus and Strength of Fiber Tubes in Radial Direction

2017 ◽  
Vol 726 ◽  
pp. 3-7
Author(s):  
Zhao Liu ◽  
Chun Lin Hu ◽  
Yi Wang Bao
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Radial Direction ◽  
Bending Strength ◽  
Potential Method ◽  
Preparation Process ◽  
Bending Modulus ◽  
Closed Ring ◽  
The Matrix ◽  
Ring Method

To explore the effects of preparation process on the mechanical properties of fiber reinforced tubes in radial direction, the closed ring method was applied to assess the elastic modulus and bending strength of GFRP and CFRP prepared by winding method and pultrusion method, respectively. The results indicate that there are two obvious differences between the winding tube and the pultrusion tube: i) the elastic modulus and bending strength of the winding tube for two materials are larger than that of the pultrusion tube. It should be attributed to the position of materials under stress: the former is the fibers while the latter is the matrix; ii) the failure mode for the winding tube is brittle fracture while elastic-plastic fracture is for the pultrusion tube. Compared with other experimental methods, the results of the closed ring method are accurate and reliable, which is demonstrated to be a potential method to evaluate the mechanical properties of fiber tubes in radial direction rapidly and conveniently.

Dependence of stress-optical coefficients on the mechanical and optical properties of polymers

1973 ◽  
Vol 8 (4) ◽  
pp. 267-276 ◽  
Author(s):  
P S Theocaris
Keyword(s):  
Mechanical Properties ◽  
Refractive Index ◽  
Optical Properties ◽  
Internal Structure ◽  
The Other ◽  
Linear Region ◽  
Non Linear ◽  
Linear Viscoelastic ◽  
Linear Viscoelastic Behaviour ◽  
The One

The internal structure of the stress-optical coefficients, as they are related to various direct interferometric methods, has been analysed and the nature of their components studied. It is shown that the stress-optical coefficients are composed of two parts. The one part depends on the variation of the mechanical properties; the other is related to the variation of the refractive index of the polymer. The influence of the mechanical properties is considerable and comparable to the influence of the optical properties. The study of the mechanical and optical contributions to the values of the stress-optical coefficients included not only the linear, but also the non-linear viscoelastic behaviour of the polymers. It is concluded that the corresponding limits of linearity of these coefficients do not coincide. Furthermore, the influence of the mechanical properties on the stress-optical coefficients is increasing relatively to the influence of the optical properties in the non-linear region.

scholarly journals Analisis Sifat Mekanik Hasil Pengelasan SMAW dengan Akar Las Tig dan Las SMAW pada Pipa API 5L

2019 ◽  
Vol 17 (1) ◽  
pp. 37
Author(s):  
Muas M ◽  
Muhammad Arsyad Suyuti ◽  
Rasul Rasul ◽  
Patta Hajji
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Bending Strength ◽  
Mechanical Tests ◽  
Current Variation ◽  
Root Face ◽  
A Current ◽  
Root Methods ◽  
Made In

The purpose of this research is to know the mechanical properties of the welds due to the current variation of welding joint API 5L using TIG and SMAW welding root methods. Preparation of specimens of pipe API 5L PSL1 grade X56 (Ø 177.8 mm, length 200 mm, width 7 mm), then specimens preparation were made in a single V 600, root gap 2mm, root face 2mm. Filling the welding roots with TIG welding and SMAW using electrodes E7018 with a current variation 70A, 80A, 90A. Mechanical tests consist of tensile, bending and hard test. The results showed that the quality of a good TIG root weld at 70A, the highest tensile strength of the weld joint 52.27 kgf/mm2 (70A), the highest hardnest 164,217 HRB (90A), the bending strength 1.123,061 N/mm2 (70A) using face bend method and 1,172,959 N/mm2 with root bend. In SMAW root welding, the highest tensile strength 54.27 kgf/mm2 (70 A) , the highest hardnest  158.717 HRB (70 A), the highest bending strength 1.115,611 N/mm2 (70 A) using face bend method, and 1.161,748 N/ mm2 with root bend. 

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