Analytical and Numerical Determination of Residual Stresses in Thick Composite Laminated Plates

In this paper, deep hole drilling method for measurement of non-uniform residual stress in thick composite laminated plates is simulated. The deep hole method is a well known method for measurement of residual stress in large metallic components. In this method, first a hole is drilled perpendicular to the surface of the laminate and the hole diameter is measured accurately after wards. Then, by trepanning process the residual stresses will be released. The hole diameter is re-measured accurately and recorded. Finally, the residual stresses can be calculated through the difference in diameter of the hole. The finite element software, ANSYS ۱۱. is used for analysis and simulation of the method. Also, for three dimensional simulation of the deep hole drilling method the three-dimensional "solid brick layered ۴۶" is used. The hole diameter was ۱۰mm that is smaller than other dimensions. First, convergence test has been applied to optimize the size of the mesh so that the results are reliable. Three types of loading Fx, Fy and Fxy were applied to finite element analysis. These results have been compared with Lekhnitskiiۥs solution and Savin ۥs for orthotropic materials. Lekhnitskii solved problems for stresses around different shapes of holes under different loads using series method. As it can be observed the results of this simulation are in good agreement with Lekhnitskiiۥs and Savin ۥs solution.