Second-Order Two-Scale Analysis Method for the Quasi-Periodic Structure of Composite Materials under Condition of Coupled Thermo-Elasticity

2012 ◽  
Vol 629 ◽  
pp. 160-164 ◽  
Author(s):  
Qiang Ma ◽  
Jun Zhi Cui

The second-order two-scale asymptotic expansions of the increment of temperature and the displacement for the quasi-periodic structure of composite materials under coupled thermo-elasticity condition are derived formally in this paper. The characteristic of the asymptotic model is the coupling between macroscopic scale and microscopic scale. Numerical examples including different coefficients are presented illustrating the efficiency and stability of the computational strategy. They show that the expansions to the second terms are necessary to obtain the thermal and mechanical behavior precisely, and the local and global oscillation of the increment of temperature and displacement are dependent on the microscopic and macroscopic part of the coefficients respectively.

2013 ◽  
Vol 14 (4) ◽  
pp. 1027-1057 ◽  
Author(s):  
Qiang Ma ◽  
Junzhi Cui

AbstractIn this paper a second-order two-scale (SOTS) analysis method is developed for a static heat conductive problem in a periodical porous domain with radiation boundary condition on the surfaces of cavities. By using asymptotic expansion for the temperature field and a proper regularity assumption on the macroscopic scale, the cell problem, effective material coefficients, homogenization problem, first-order correctors and second-order correctors are obtained successively. The characteristics of the asymptotic model is the coupling of the cell problems with the homogenization temperature field due to the nonlinearity and nonlocality of the radiation boundary condition. The error estimation is also obtained for the original solution and the SOTS’s approximation solution. Finally the corresponding finite element algorithms are developed and a simple numerical example is presented.


2014 ◽  
Vol 36 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Dariusz Łydżba ◽  
Adrian Różański ◽  
Magdalena Rajczakowska ◽  
Damian Stefaniuk

Abstract The needle probe test, as a thermal conductivity measurement method, has become very popular in recent years. In the present study, the efficiency of this methodology, for the case of composite materials, is investigated based on the numerical simulations. The material under study is a two-phase composite with periodic microstructure of “matrix-inclusion” type. Two-scale analysis, incorporating micromechanics approach, is performed. First, the effective thermal conductivity of the composite considered is found by the solution of the appropriate boundary value problem stated for the single unit cell. Next, numerical simulations of the needle probe test are carried out. In this case, two different locations of the measuring sensor are considered. It is shown that the “equivalent” conductivity, derived from the probe test, is strongly affected by the location of the sensor. Moreover, comparing the results obtained for different scales, one can notice that the “equivalent” conductivity cannot be interpreted as the effective one for the composites considered. Hence, a crude approximation of the effective property is proposed based on the volume fractions of constituents and the equivalent conductivities derived from different sensor locations.


Sign in / Sign up

Export Citation Format

Share Document