Numerical analysis of physical problems developed in the 20th century with the development of computers that have the capacity to execute complex and long mathematical operations in a short period of time. Prior to the development of computers such analysis were done manually, which was a very long, hard-working and impractical job. As the operating capability of computers grows we are able to define more complex numerical models in order to approximate a better real state of the structure and getting more accurate results. The finite element method is a numerical method used to solve complex engineering problems and problems of mathematical physics. We use the finite element method when we are not able to solve the model directly analytically. The discretized model is composed of finite elements that are connected with nodes, lines, or common areas depending on whether it is a line, plane or volume finite element. Solving the model is reduced to the solving a predefined system of algebraic equations. Shells are load-bearing elements which surface has a single or double curvature. The load capacity of a shell is better than the load capacity of plates because a proper designed shell can transfer a big part of the load to the supports through its surface. In theory, construction of a shell is a very complex area and the theory of thin shells is more complex than the theory of plate. Shell finite elements are classified into three main groups: flat shell finite elements, curved shell finite elements and three-dimensional shell finite elements.