Estimation of stress concentration factor of composite lamina with triangular hole using multiple linear regression

The purpose of this paper is to present a new model based on the multiple regression method for estimating stress concentration factor of a quasi-triangular hole in composite lamina. One of the important applications of providing stress distribution around holes in terms of mechanical properties is the use of these relationships in the stress analysis of perforated viscoelastic plate using the effective modulus method or Boltzmann's superposition principle. First, using different values of the mechanical properties of the composites plates, and employing an analytical solution based on the complex variable method, the stress concentration factor of quasi-triangular hole is calculated for a number of these materials. Then, using multiple linear regression, An explicit expression for the stress concentration factor is given in terms of mechanical properties. The results show that the multiple regression model is able to predict the circumferential stress with a maximum error of less than 1%. An important point in this article is the reduction of the calculations by applying the aforementioned relations. In other papers in this field, hard and complex calculations were used to obtained the stress concentration factors, but with the help of the relation of this paper, it is to calculate the stress concentration factor with having the mechanical properties of the plate.