Variations in Transverse Fibre Wall Properties: Relations Between Elastic Properties and Structure

Holzforschung ◽  
2000 ◽  
Vol 54 (6) ◽  
pp. 654-660 ◽  
Author(s):  
A. Bergander ◽  
L. Salmén

Summary The transverse mechanical properties of the wood fibre play important roles in the use of wood and its fibres in various applications. However, the variation in properties of fibres from different parts of the tree and the relation of these properties to the structure of the fibre is not yet established. This study focuses on the variation in the transverse elastic modulus of the fibre wall and its relation to the fibril structure of the S2- and S1-layer. For this reason the local fibril angle of radial and tangential fibre walls were measured by polarisation confocal microscopy. It was shown that the variation in fibril angle of the S2-layer seems to have very little influence on the transverse modulus of the fibres. Instead the thickness and fibril angle of the S1- and thus also the S3-layer should contribute to the variation in transverse modulus between earlywood and transition wood fibres. The importance of the ray cells for the transverse elastic properties of the wood was also emphasised.

2015 ◽  
Vol 44 (43) ◽  
pp. 18769-18779 ◽  
Author(s):  
Philippe F. Weck ◽  
Eunja Kim ◽  
Veena Tikare ◽  
John A. Mitchell

The elastic properties and mechanical stability of zirconium alloys and zirconium hydrides have been investigated within the framework of density functional perturbation theory. Results show that the lowest-energy Pn3̄m δ-ZrH1.5 phase is not mechanically stable.


1989 ◽  
Vol 4 (6) ◽  
pp. 1347-1353 ◽  
Author(s):  
T. G. Nieh ◽  
J. Wadsworth ◽  
C. T. Liu

The elastic properties of nickel beryllide have been evaluated from room temperature to 1000 °C. The room temperature modulus is measured to be 186 GPa, which is relatively low by comparison with other B2 aluminides such as NiAl and CoAl. Hardness measurements were carried out on specimens that had compositions over the range from 49 to 54 at. % Be, using both a Vickers microhardness tester and a nanoindentor. It was found that the hardness of NiBe exhibits a minimum at the equiatomic composition. This behavior is similar to that of aluminides of the same crystal structure, e.g., NiAl and CoAl. The effect of interstitial oxygen on the hardness of NiBe has also been studied and the results show that the presence of oxygen in NiBe can cause a significant increase in hardness. It is demonstrated that the hardness increase for the off-stoichiometric compositions is primarily caused by interstitial oxygen and can only be attributed partially to anti-site defects generated in off-stoichiometric compositions. Nickel beryllides appear to have some intrinsic room temperature ductility, as evidenced by the absence of cracking near hardness indentations.


Physiology ◽  
1995 ◽  
Vol 10 (1) ◽  
pp. 30-35 ◽  
Author(s):  
LW Welling ◽  
MT Zupka ◽  
DJ Welling

Basement membranes from renal tubules, capillaries, venules, and pulmonary alveolar wall all have remarkably similar elastic properties and Young's moduli. Strength and safety margin, however, are far smaller in the alveolar wall, perhaps as a result of its complexity of design.


This paper presents the investigation of moderate properties of solidified Al (LM6)+SiCp metal matrix composite (AMMC). These AMMC is fabricated by considering five different parts of casting and different weight of SiCp for reinforcement. The SiCp wt. % is varied from 5 wt. % to 15 wt. % with a step size 5 %. During casting, temperature is measured using K-thermocouple and temperature vs. solidification curve is traced. These results are compared with the solidification results of Al (LM6) alloy. It is observed that the solidifying duration of AMMC increased as well as decreased liquid temperature by adding SiCp to it. The trend of the curve is also presented that the cooling rate and the duration of solidification are different for different part of casting. Mechanical property of the each five parts of casting is tabulated. It is observed from the properties that the mechanical properties of AMMC increased by increasing the wt. % of the reinforced particles SiCp.


2017 ◽  
Vol 67 (2) ◽  
pp. 85-90
Author(s):  
Zdeněk Padovec ◽  
Radek Sedláček ◽  
Milan Růžička ◽  
Pavel Růžička

AbstractPresented work describes the use of algorithm for the computation of thermo-elastic properties of randomly reinforced composite which is based on histogram from image analysis done on ITAM, CAS. Three polished samples from “Bearing” part were analyzed. Results are used for verification of the algorithm functionality and primarily for computation of thermo-elastic properties which were compared with each other and used in modified FE analysis.


2021 ◽  
Vol 223 (1) ◽  
pp. 68-80
Author(s):  
Thanit Saisopa ◽  
Chakrit Nualchimplee ◽  
Yuttakarn Rattanachai ◽  
Kompichit Seehamart ◽  
Isara Kotutha ◽  
...  

2019 ◽  
Vol 274 ◽  
pp. 05004
Author(s):  
Zhiyuan Lin ◽  
Ding Fan ◽  
Shangtong Yang

Cementitious nano-composites have recently attracted considerable research interest in order to improve their properties such as strength and durability. Graphene oxide (GO) is being considered as an ideal candidate for enhancing the mechanical properties of the cement due to its good dispersion property and high surface area. Much of work has been done on experimentally investigating the mechanical properties of GO-cementitious composites; but there are currently no models for accurate estimation of their mechanical properties, making proper analysis and design of GO-cement based materials a major challenge. This paper attempts to develop a novel multi-scale analytical model for predicting the elastic modulus of GO-cement taking into account the GO/cement ratio, porosity and mechanical properties of different phases. This model employs Eshelby tensor and Mori-Tanaka solution in the process of upscaling the elastic properties of GO-cement through different length scales. In-situ micro bending tests were conducted to elucidate the behavior of the GO-cement composites and verify the proposed model. The obtained results showed that the addition of GO can change the morphology and enhance the mechanical properties of the cement. The developed model can be used as a tool to determine the elastic properties of GO-cement through different length scales.


2019 ◽  
Vol 98 (12) ◽  
pp. 6393-6399
Author(s):  
Shujie Wang ◽  
Yunxiao Hu ◽  
Yiling Wu ◽  
Yawen Liu ◽  
Guoqing Liu ◽  
...  

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