Generation of Three-Dimensional Microstructure Model for Discontinuously Reinforced Composite by Modified Random Sequential Absorption Method

Author(s):  
Jiming Zhou ◽  
Lehua Qi ◽  
Arun M. Gokhale

Computer simulation of mechanical behavior of discontinuously reinforced composites containing randomly oriented short-fibers/whiskers presents an attractive opportunity for reduction of the number of experiments and resources required for microstructure design of such advanced materials. It is desirable to perform such simulations using microstructure model that accounts for randomness in angular orientations and locations of the short fibers/whiskers. In this contribution, a methodology is presented for efficient simulation of the required microstructural model through modification of well-known random sequential adsorption (RSA) algorithm for microstructure simulation through its application to the microstructure of Mg–alloy matrix composite containing randomly oriented short carbon fibers. The modified RSA algorithm enhances accuracy and efficiency of the complex geometric details of the randomly oriented short-fiber reinforced composite microstructure. Simulated microstructural model of composite is implemented in abaqus to simulate the mechanical response of the Mg–matrix composite containing randomly oriented short carbon fibers. The generated complex microstructure model in abaqus code is sliced into thin slices for reducing computing resources. The simulated results from multiple sliced models were averaged to approximate the result for the full volume element. The simulated mechanical response by use of multiple sliced models is validated via comparison with the experimental data.

1994 ◽  
Vol 360 ◽  
Author(s):  
Pu-Woei Chen ◽  
D.D.L. Chung

AbstractConcrete containing short carbon fibers (0.2-0.5 vol.%) was found to be an intrinsically smart concrete that can sense elastic and inelastic deformation, and fracture. The signal provided is the change in electrical resistance, which is reversible for elastic deformation and irreversible for inelastic deformation and fracture. The presence of electrically conducting short fibers is necessary for the concrete to sense elastic or inelastic deformation, but the sensing of fracture does not require fibers. The fibers serve to bridge the cracks and provide a conduction path. The resistance increase is due to conducting fiber pull-out in the elastic regime, conducting fiber breakage in the inelastic regime, and crack propagation at fracture.


2015 ◽  
Vol 15 (3) ◽  
pp. 39-42 ◽  
Author(s):  
M. Łągiewka ◽  
Z. Konopka

Abstract The presented work describes the results of examination of the mechanical properties of castings made either of AlSi9Mg alloy matrix composite reinforced with short carbon fibre or of the pure AlSi9Mg alloy. The tensile strength, the yield strength, Young’s modulus, and the unit elongation were examined both for initial castings and for castings made of the remelted composite or AlSi9Mg alloy. After preparing metallographic specimens, the structure of the remelted materials was assessed. A few non-metallic inclusions were observed in the structure of the remelted composite, not occurring in the initial castings. Mechanical testing revealed that all the examined properties of the initial composite material exceed those of the non-reinforced matrix. A decrease in mechanical properties was stated both for the metal matrix and for the composite after the remelting process, but this decrease was so slight that it either does not preclude them from further use or does not restrict the range of their application.


1999 ◽  
Vol 121 (3) ◽  
pp. 386-392
Author(s):  
Jiang Xiaoyu ◽  
Kong Xiangan

In this paper, the microstructure of “Saffil”-Al2O3 short fiber reinforced Al-Mg5.5 metal matrix composite material is simulated by computer. In the simulation it is taken into account of that the lengths, diameters, orientations, and locations of short fibers, etc. For the 3-D randomly distributed short fibers in composite materials, the typical distributions of short fiber microstructures on different planes are obtained for different short fiber volume fractions. The microstructural effects of average fiber length, diameter and their standard deviations on the overall strength of metal matrix composite materials are analyzed. From the short fiber microstructural distribution in metal matrix composite materials, the short fiber diameter coefficient ξd and short fiber length coefficient ξ1 are obtained for different standard deviations σd and σl, respectively. The short fiber orientation coefficient ξa is obtained, also. The results of these coefficients may be useful to the manufacture and use of short fiber reinforced composite materials. Considering these coefficients ξa ξd and ξl, the improved formula is given for the direct calculation of overall strength of short fibers reinforced composite materials. The improved formula may reflect the microstructural characteristics of short fibers reinforced composite materials.


2010 ◽  
Vol 139-141 ◽  
pp. 113-116
Author(s):  
Jun Tian ◽  
Wen Fang Li ◽  
Shou Yan Zhong ◽  
Ji Hua Peng

AZ91 magnesium matrix composite was fabricated by squeeze infiltration process. The aluminum silicate short fibers were used as reinforcement, and aluminum phosphate was adopted as binder, fabricating process was improved as well as reducing fabricating cost effectively. The optimum technique of squeeze casting, that was, preform-body temperature of 6600C, mould temperature of 5600C, pouring temperature of 7600C and pressure of 30~50MPa. The reaction products were investigated by optical microscopic, XRD and SEM. The results show that an ideal stronger interface is formed by the chemical reaction between magnesium alloy matrix and aluminum phosphate binder due to the produce of MgO particles and a little MgAl2O4 particles in the interface. AZ91 magnesium matrix composite is well-organized, and its grain size is significantly smaller than that of the matrix. The structure of AZ91 magnesium matrix composite is uniform without casting defects such as shrinkages and inclusions.


1999 ◽  
Vol 14 (3) ◽  
pp. 790-802 ◽  
Author(s):  
Xiaojun Wang ◽  
Xuli Fu ◽  
D. D. L. Chung

Carbon fiber provides strain sensing through change in electrical resistance upon strain. Due to piezoresistivity of various origins, a single carbon fiber in epoxy, an epoxy-matrix composite with short carbon fibers (5.5 vol%), a cement-matrix composite with short carbon fibers (0.2–0.5 vol%), and an epoxy-matrix composite with continuous carbon fibers (58 vol%) are strain sensors with fractional change in resistance per unit strain up to 625. A single bare carbon fiber is not piezoresistive, but just resistive.


2009 ◽  
Vol 255 (13-14) ◽  
pp. 6647-6651 ◽  
Author(s):  
Zeng Jun ◽  
Xu Jincheng ◽  
Hua Wei ◽  
Xia Long ◽  
Deng Xiaoyan ◽  
...  

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