MULTI-SCALE CREEP ANALYSIS OF PLAIN-WOVEN LAMINATES USING TIME-DEPENDENT HOMOGENIZATION THEORY: EFFECTS OF LAMINATE CONFIGURATION

2009 ◽  
Author(s):  
K. NAKATA ◽  
T. MATSUDA ◽  
M. KAWAI
Keyword(s):  
Time Dependent ◽  
Homogenization Theory ◽  
Multi Scale ◽  
Creep Analysis

MULTI-SCALE CREEP ANALYSIS OF PLAIN-WOVEN LAMINATES USING TIME-DEPENDENT HOMOGENIZATION THEORY: EFFECTS OF LAMINATE CONFIGURATION

2008 ◽  
Vol 22 (31n32) ◽  
pp. 6173-6178 ◽  
Author(s):  
K. NAKATA ◽  
T. MATSUDA ◽  
M. KAWAI
Keyword(s):  
Boundary Condition ◽  
Glass Fiber ◽  
Creep Behavior ◽  
Present Method ◽  
Time Dependent ◽  
Homogenization Theory ◽  
Multi Scale ◽  
Creep Analysis ◽  
Internal Structures ◽  
Woven Glass Fiber

In this study, multi-scale creep analysis of plain-woven GFRP laminates is performed using the time-dependent homogenization theory developed by the present authors. First, point-symmetry of internal structures of plain-woven laminates is utilized for a boundary condition of unit cell problems, reducing the domain of analysis to 1/4 and 1/8 for in-phase and out-of-phase laminate configurations, respectively. The time-dependent homogenization theory is then reconstructed for these domains of analysis. Using the present method, in-plane creep behavior of plain-woven glass fiber/epoxy laminates subjected to a constant stress is analyzed. The results are summarized as follows: (1) The in-plane creep behavior of the plain-woven GFRP laminates exhibits marked anisotropy. (2) The laminate configurations considerably affect the creep behavior of the laminates.

Macro/Meso/Micro Elastic-Viscoplastic Analysis of Plain-Woven Laminates Using Homogenization Theory

2014 ◽  
Vol 626 ◽  
pp. 365-371 ◽  
Author(s):  
Kohei Oide ◽  
Tetsuya Matsuda
Keyword(s):  
Experimental Data ◽  
Constitutive Equation ◽  
Glass Fiber ◽  
Present Method ◽  
Time Dependent ◽  
Homogenization Theory ◽  
Fiber Bundles ◽  
Woven Glass Fiber ◽  
Good Agreement

In this study, macro/meso/micro elastic-viscoplastic analysis of plain-woven laminates is conducted based on a homogenization theory for nonlinear time-dependent composites. For this, a plain-woven laminate is modeled with respect to three scales by considering the laminate as a macrostructure, fiber bundles (yarns) and a matrix in the laminate as a mesostructure, and fibers and a matrix in the yarns as a microstructure. Then, an elastic-viscoplastic constitutive equation of the laminate is derived by dually applying the homogenization theory for nonlinear time-dependent composites to not only the meso/micro but also the macro/meso scales. Using the present method, the elastic-viscoplastic analysis of a plain-woven glass fiber/epoxy laminate subjected to on-and off-axis loading is performed. It is shown that the present method successfully takes into account the effects of viscoplasticity of the epoxy in yarns on the elastic-viscoplastic behavior of the plain-woven GFRP laminate. It is also shown that the results of analysis are in good agreement with experimental data.

Analytical Solution for the Creep Problem of a Rotating Functionally Graded Magneto–Electro–Elastic Hollow Cylinder in Thermal Environment

2019 ◽  
Vol 11 (06) ◽  
pp. 1950053 ◽  
Author(s):  
M. Saadatfar
Keyword(s):  
Differential Equation ◽  
Hollow Cylinder ◽  
Thermal Loading ◽  
Thermal Environment ◽  
Functionally Graded ◽  
Time Dependent ◽  
Creep Stress ◽  
Creep Analysis ◽  
Magnetic Potentials ◽  
Creep Strains

In this paper, an analytical method is presented for the problem of the time-dependent response of a functionally graded magneto–electro–elastic (FGMEE) rotating hollow cylinder in thermal environment. The material properties of FGMEE are supposed to be power-law functions of radius. Applying the equations of equilibrium and electrostatic and magnetostatic equations, a differential equation which includes creep strains is achieved. At first, an exact solution for the primitive stresses, electric and magnetic potentials are achieved by eliminating creep strains in the mentioned differential equation. Then, Prandtl–Reuss equations, as well as Norton’s law, are employed for the FGMEE. Now, creep stress rates can be achieved by considering only creep strains in the mentioned differential equation. As a final step, time-dependent creep stress, electric potential and magnetic potential redistributions at any time can be achieved using an iterative method. Numerical examples are presented to disclose the influence of creep evolution, thermal loading, angular velocity and grading index on the primitive and creep response of the FGMEE hollow cylinder. Results show that the enhancement in tensile hoop stress during the creep evolution must be considered in designing. So, the creep analysis is vital to have more reliable and accurate aerospace smart structures.

Elastic-Viscoplastic Behaviour of Plain-Woven GFRP Laminates: Analysis Using Homogenization Theory

2007 ◽  
Vol 334-335 ◽  
pp. 45-48
Author(s):  
Tetsuya Matsuda ◽  
Y. Nimiya ◽  
Nobutada Ohno ◽  
Masamichi Kawai
Keyword(s):  
Present Method ◽  
Room Temperature ◽  
Constant Strain Rate ◽  
Tensile Tests ◽  
Time Dependent ◽  
Homogenization Theory ◽  
Point Symmetry ◽  
Quantitative Prediction ◽  
Viscoplastic Deformation ◽  
Internal Structures

In the present study, a method for reducing the domain of analysis is developed for the homogenization analysis of plain-woven laminates. Moreover, the method is applied to the quantitative prediction of elastic-viscoplastic deformation of plain-woven GFRP laminates. It is first shown that the internal structures of plain-woven laminates satisfy point-symmetry on the assumption that the laminates have the in-phase or out-of-phase laminate configuration of plain fabrics. The point-symmetry is then utilized for the boundary condition of unit cell problems, reducing the domain of analysis to 1/4 and 1/8 for the in-phase and out-of-phase laminate configurations, respectively. Using the present method combined with the nonlinear time-dependent homogenization theory, the elastic-viscoplastic behavior of plain-woven GFRP laminates under in-plane on- and off-axis loading is analyzed. In addition, the tensile tests of a plain-woven GFRP laminate at a constant strain rate are performed at a room temperature. Comparing the results of the present analysis with the experimental ones, it is shown that the analysis successfully predicts the in-plane elastic-viscoplastic behavior of the plain-woven GFRP laminate.

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