Abstarct: Failure is usually due to geometric discontinuities such as cracks, openings, poses and heights, and any other discontinuities, which is why one of the most important issues in designing structures. The main reason for the failure of the material is to reduce the strength of the material and to create a stress concentration. With increasing tensions, these discontinuities grow and lead to discontinuity and damage growth that ultimately leads to the ultimate failure of matter. Exact Material Behavior Despite Discontinuity, Helps designers make the most effective design from the material. In addition to the hole geometry and its placement in relation to the loading and radius of curvature of the openings in the material behavior, it will be very effective. In this thesis, the distribution of stress around quasi-square hole in an infinity orthotropic-viscoelastic plate under axial loading has been investigated using the effective modulus method and the Boltzmann's superposition principle and the corresponding method. First, the stress distribution around the quasi-square opening in one The infinity orthotropic platet is calculated using the Lekhnitskii complex variable method in terms of the function of mechanical properties E1, E2, G12, υ_12. Then, using the Boltzmann's superposition principle and the method of corresponding method, the solution of the elastic problem turns into a viscoelastic solution in the Laplace area. Then, by inversing Laplace in reciprocal numerical methods, the viscoelastic solution in the time domain is also obtained. Finally, using a multiple linear regression for quasi-square hole, an explicit relationship is also proposed for stress components baxsed on mechanical properties. Then the effect of the curvature parameters of hole and rotation angle is also presented. Finally, the linear regression function is baxsed on six parameters, including four composite material parameters and two parameters of the angle and rotation of curvature of the hole.