Realization of Mechanical Properties Prediction from Nano- to Macro- Scale Structure: An Achievement of C-S-H Hydrated Phases

2019 ◽  
Vol 956 ◽  
pp. 332-341 ◽  
Author(s):  
Jia Fu
Keyword(s):  
Mechanical Properties ◽  
High Density ◽  
Theoretical Research ◽  
Step Method ◽  
Material Technology ◽  
Micro Scale ◽  
Nano Scale ◽  
Macro Scale ◽  
Mechanical Properties Prediction ◽  
Technology Modeling

The performance prediction of C-S-H gel is critical to the theoretical research of cement-based materials. In the light of recent computational material technology, modeling from nano-scale to micro-scale to predict mechanical properties of structure has become research hotspots. This paper aims to find the inter-linkages between the monolithic "glouble" C-S-H at nano-scale and the low/high density C-S-H at the micro-scale by step to step method, and to find a reliable experimental verification method. Above all, the basic structure of tobermorite and the "glouble" C-S-H model at nano-scale are discussed. At this scale, a "glouble" C-S-H structure of about 5.5 nm3 was established based on the 11Å tobermorite crystal, and the elastic modulus ​​of the isotropic "glouble" is obtained by simulation. Besides, by considering the effect of porosity on the low/high density of the gel morphology, the C-S-H phase at micro-scale can be reversely characterized by the "glouble". By setting different porosities and using Self-Consistent and Mori-Tanaka schemes, elastic moduli of the low density and high density C-S-H ​​from that of "glouble" are predicted, which are used to compare with the experimental values of the outer and inner C-S-H. Moreover, the nanoindentation simulation is carried out, where the simulated P-h curve is in good agreement with the accurate experimental curve in nanoindentation experiment by the regional indentation technique(RET), thus the rationality of the "glouble" structure modeled is verified and the feasibility of Jennings model is proved. Finally, the studies from the obtained ideal "glouble" model to the C-S-H phase performance has realized the mechanical properties prediction of the C-S-H structure from nano-scale to micro-scale, which has great theoretical significance for the C-S-H structural strengthening research.

Microstructure and Mechanical Properties of Multi-Scale Titanium Diboride Matrix Nanocomposite Ceramic Tool Materials

2010 ◽  
Vol 431-432 ◽  
pp. 523-526
Author(s):  
Han Lian Liu ◽  
Chuan Zhen Huang ◽  
Shou Rong Xiao ◽  
Hui Wang ◽  
Ming Hong
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Transgranular Fracture ◽  
Ceramic Tool ◽  
Tool Materials ◽  
Micro Scale ◽  
Multi Scale ◽  
Nano Scale ◽  
Matrix Nanocomposite

Under the liquid-phase hot-pressing technique, the multi-scale titanium diboride matrix nanocomposite ceramic tool materials were fabricated by adding both micro-scale and nano-scale TiN particles into TiB2 with Ni and Mo as sintering aids. The effect of content of nano-scale TiN and sintering temperature on the microstructure and mechanical properties was studied. The result showed that flexural strength and fracture toughness of the composites increased first, and then decreased with an increase of the content of nano-scale TiN, while the Vickers hardness decreased with an increase of the content of nano-scale TiN. The optimal mechanical properties were flexural strength 742 MPa, fracture toughness 6.5 MPa•m1/2 and Vickers hardness 17GPa respectively. The intergranular and transgranular fracture mode were observed in the composites. The metal phase can cause ductility toughening and crack bridging, while crack deflection and transgranular fracture mode could be brought by micro-scale TiN and nano-scale TiN respectively.

scholarly journals Cells spreading on Micro-fabricated Silica Thin film Coatings

2009 ◽  
Vol 15 (S3) ◽  
pp. 77-78 ◽  
Author(s):  
A. Pelaez-Vargas ◽  
N. Ferrell ◽  
M. H. Fernandes ◽  
D. Hansford ◽  
F. J. Monteiro
Keyword(s):  
Fibrous Layer ◽  
Micro Scale ◽  
Film Coatings ◽  
Thin Film Coatings ◽  
Nano Scale ◽  
Complex Process ◽  
Macro Scale ◽  
Silica Thin Film ◽  
Scale Roughness ◽  
Material Interaction

AbstractFrom a biomaterials perspective, it is now understood that success in the osseointegration of a dental implant is conditioned by its “macro”, “micro” and “nano” scale features. Macro-scale roughness is necessary to improve primary stabilization in the post-surgical phase inducing a peri-implant thin fibrous layer. However, the more complex process in the true cell-material interaction is dependent on micro and nano scale phenomena. There is clear evidence that cell adhesion, proliferation, organization and phenotype are modulated at the micro-scale and that protein absorption is fundamentally a process conditioned at nano-scale.

Micro-Scale Strength Evaluation for Bonding Interface of Cold Sprayed Coatings

2016 ◽  
Vol 879 ◽  
pp. 795-800 ◽  
Author(s):  
Yuji Ichikawa ◽  
Ryotaro Tokoro ◽  
Kazuhiro Ogawa
Keyword(s):  
Mechanical Properties ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Strain Curve ◽  
Stress Strain Curve ◽  
Strength Evaluation ◽  
Scale Evaluation ◽  
Micro Scale ◽  
Macro Scale ◽  
Sprayed Coatings

A micro-scale interface strength evaluation technique is essential for evaluating cold-sprayed materials. A focused ion beam (FIB) micro strength test enables the micro-scale evaluation of the interface mechanical properties. However, this technique cannot be used to measure the strain in a specimen. This work discusses the possibility of strain measurement by combining this technique with image analysis in a newly designed test setup. Moreover, the micro stress-strain curve for cold-sprayed copper was obtained. This improved method enables us to measure stress with a precision of 5 MPa and strain with a precision of 0.015. It was determined that some local regions can deform plastically, which could not be determined with conventional micro-and macro-scale evaluation methods. These results proved that the coating is non-uniform, while also revealing various microstructure and mechanical properties.

Microstructure and Mechanical Properties of two Kinds of Al2O3/SiC Nanocomposites

2004 ◽  
Vol 471-472 ◽  
pp. 243-247 ◽  
Author(s):  
Han Lian Liu ◽  
Chuan Zhen Huang ◽  
Jun Wang ◽  
Jing Sun
Keyword(s):  
Mechanical Properties ◽  
Alumina Powder ◽  
Transgranular Fracture ◽  
Alumina Ceramics ◽  
Ceramic Tool ◽  
Tool Materials ◽  
Micro Scale ◽  
Nano Scale ◽  
Monolithic Alumina ◽  
Al2o3 Matrix

Two kinds of Al2O3 /SiC nanocomposites with different alumina powder are developed, one is fabricated only by nano-scale alumina powders, the other is by micro-scale with partial nano-scale alumina powders. Both of the two composites may get higher flexural strength and fracture toughness than that of micro-scale monolithic alumina ceramics, but the latter is more preferable than the former. The microstructure and the strengthening and toughening mechanisms of the new ceramic tool materials are investigated, the improvement of mechanical properties may be mainly attributed to the transgranular fracture mode induced by the added nano-scale SiC, while adding nano-scale alumina powder to micro-scale powder, both of the nano-scale Al2O3 and nano-scale SiC may strengthen the micro-scale Al2O3 matrix, that means the nano-scale Al2O3 acted as the dispersed phase.

Effect of Nano-Additives on Microstructure and Mechanical Properties of Ti(C,N)-TiB2-WC Composite Ceramic Cutting Tool Materials

2013 ◽  
Vol 589-590 ◽  
pp. 337-341 ◽  
Author(s):  
Yue Liu ◽  
Chuan Zhen Huang ◽  
Han Lian Liu ◽  
Bin Zou ◽  
Peng Yao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cutting Tool ◽  
Composite Ceramic ◽  
Hot Press ◽  
Tool Materials ◽  
Micro Scale ◽  
Ceramic Cutting Tool ◽  
Nano Scale ◽  
Microstructure And Mechanical Properties ◽  
Cutting Tool Materials

Ti(C,N)-TiB2-WC composite ceramic cutting tool materials with nano-scale additives Ni and Mo, and micro-scale additives Ni and Mo as sintering aids were sintered respectively at a temperature of 1550 °C for holding time of 1hour in vacuum by a hot-press technique. The effects of nano-scale additives Ni and Mo, and micro-scale additives Ni and Mo on microstructure and mechanical properties of composites were compared and investigated. It is concluded that the wettability of nano-scale Ni and Mo to the composites is better than that of micro-scale Ni and Mo. The nano-scale whiskers were found in the composite ceramic tool materials with nano-scale additives. The addition of nano-scale Ni and Mo instead of micro-scale Ni and Mo could make the flexural strength and fracture toughness of Ti(C, N)-TiB2 –WC composites have a promotion, but could not make the hardness of the composites increase in this study.

Multi-Scale Modeling of Fracture Properties for Nano-Particle Reinforced Polymers Using Atomistic J-Integral

2014 ◽  
Author(s):  
Samit Roy ◽  
Avinash Akepati
Keyword(s):  
Mechanical Properties ◽  
Free Energy ◽  
Crack Initiation ◽  
Model Verification ◽  
Total System ◽  
J Integral ◽  
Nano Particle ◽  
Nano Scale ◽  
Macro Scale ◽  
Definition Of

The nano-scale interaction between polymer molecules and nanoparticle is a key factor in determining the macro-scale strength of the composite. In recent years numerous efforts have been directed towards modeling nanocomposites in order to better understand the reasons behind the enhancement of mechanical properties, even by the slight addition (a few weight percent) of nano-materials. In order to better understand the local influence of nano-particle on the mechanical properties of the composite, it is required to perform nano-scale analysis. In this context, modeling of fracture and damage in nano-graphene reinforced EPON 862 has been discussed in the current paper. Regarding fracture in polymers, the critical value of the J-integral (JI), where the subscript I denotes the fracture mode (I=1, 2, 3), at crack initiation could be used as a suitable metric for estimating the crack driving force as well as fracture toughness of the material as the crack begins to initiate. However, for the conventional macroscale definition of the J-integral to be valid at the nanoscale, in terms of the continuum stress and displacement fields and their spatial derivatives — requires the construction of local continuum fields from discrete atomistic data, and using these data in the conventional contour integral expression for atomistic J-integral. One such methodology is proposed by Hardy that allows for the local averaging necessary to obtain the definition of free energy, deformation gradient, and Piola-Kirchoff stress as fields (and divergence of fields) and not just as total system averages. Further, the atomistic J-integral takes into account the effect of reduction in J from continuum estimates due to the fact that the free energy available for crack propagation is less than the internal energy at sufficiently high temperatures when entropic contributions become significant. In this paper, the proposed methodology is used to compute J-integral using atomistic data obtained from LAMMPS (Large-scale Atomic/Molecular Massively Parallel Simulator). As a case study, the feasibility of computing the dynamic atomistic J-integral over the MD domain is evaluated for a graphene nano-platelet with a central crack using OPLS (Optimized Potentials for Liquid Simulations) potential. For model verification, the values of atomistic J-integral are compared with results from linear elastic fracture mechanics (LEFM) for isothermal crack initiation at 0 K and 300 K. Computational results related to the path-independence of the atomistic J-Integral are also presented. Further, a novel approach that circumvents the complexities of direct computation of entropic contributions is also discussed. Preliminary results obtained from the bond-order based ReaxFF potential for 0.1 K and 300 K are presented, and show good agreement with the predictions.

Microstructure and Mechanical Properties of Nano-Scale Al2O3 Toughened Ti (C,N) Matrix Cermet Tool Materials

2006 ◽  
Vol 532-533 ◽  
pp. 37-40 ◽  
Author(s):  
Chuan Zhen Huang ◽  
Jun Wang ◽  
Li Qiang Xu ◽  
Sui Lian Wang ◽  
Han Lian Liu
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Vickers Hardness ◽  
Tool Material ◽  
Al2o3 Powder ◽  
Tool Materials ◽  
Micro Scale ◽  
Nano Scale ◽  
Microstructure And Mechanical Properties

Advanced Ti(C, N) matrix cermet tool materials with higher mechanical properties are successfully developed by dispersing nano-scale Al2O3 powder into the micro-scale Ti(C, N) matrix and Ni-Mo bonding phases powder. The effect of the content of nano-scale alumina on the microstructure and mechanical properties of micro-scale Ti(C, N) matrix cermet tool materials are investigated. The research results show that a type of Ti(C, N) matrix cermet tool material has the most optimal flexural strength of 900MPa, Vickers hardness of 17.4GPa and fracture toughness of 9.95MPa.m1/2 when the content of nano-scale alumina is 12% in term of mass. It is found from the microstructure analysis that the main reason of the mechanical properties improvement is the grain fining effect caused by nano-scale Al2O3.

Effect of Dynamic Crosslinking on Mechanical Properties of PP/EPDM Blends

1993 ◽  
Vol 58 (11) ◽  
pp. 2642-2650 ◽  
Author(s):  
Zdeněk Kruliš ◽  
Ivan Fortelný ◽  
Josef Kovář
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Shear Modulus ◽  
High Impact ◽  
Necessary Condition ◽  
Step Method ◽  
Melt Mixing ◽  
One Step ◽  
High Impact Strength ◽  
Dynamic Curing

The effect of dynamic curing of PP/EPDM blends with sulfur and thiuram disulfide systems on their mechanical properties was studied. The results were interpreted using the knowledge of the formation of phase structure in the blends during their melt mixing. It was shown, that a sufficiently slow curing reaction is necessary if a high impact strength is to be obtained. Only in such case, a fine and homogeneous dispersion of elastomer can be formed, which is the necessary condition for high impact strength of the blend. Using an inhibitor of curing in the system and a one-step method of dynamic curing leads to an increase in impact strength of blends. From the comparison of shear modulus and impact strength values, it follows that, at the stiffness, the dynamically cured blends have higher impact strength than the uncured ones.

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