Stress Analysis of Fiber-reinforced Composite Built-up Beam  
Using the Unit Cell Method  
 
 
Dr. Haydar A. Hussain                  Dr. Ala’a M. Hussain               Luay M. Ali  

Babylon
University                           
Babylon
University                     

Babylon
University  

College of
Engineering                     
College of
Engineering              

College of
Engineering  

Dept. of Materials Eng.                 Dept. of mech.
Eng.                 Dept. of mech.
Eng.  
 Draletharihah@yahoo.com                                                             luya_m_63@yahoo.com  
                                                                                     
ABSRACT  
   Macro- and microscopic levels of analyses are used to capture the behavior of a built-in beam made of a unidirectional fiber-reinforced polymeric material. Finite element formulation based on the displacement approach and minimum potential energy principle is carried out in the longitudinal direction of the beam to determine the lateral displacements (deflections) at various sections, stresses and strains. A unit cell method in micromechanical analysis based on the finite element method is used to define the state and distribution of the stresses induced in transverse sections. Hexagonal fiber-matrix packing system is idealized for the problem. The package of ANSYS 5.4 and a Matlab v6.5 program are used to solve for the macro- and micromechanical analyses. To examine the validity of the presented method, it is applied to analyze a beam made of matrix and fibers with the same elastic properties. The results are then compared with those obtained using the method followed for isotropic materials considering the same values of the elastic properties , the convergence obtained verifies the validity of the analysis method adopted by the current work.