Mohammad Iman Khodakarami - Ph.D. Student of Earthquake Engineering, Faculty of Civil and Environmental Engineering, Tarbiat Modares University, Tehran, Iran
Naser Khaji - Associate Professor of Earthquake Engineering, Faculty of Civil and Environmental Engineering,Tarbiat Modares University, Tehran, Iran

In this paper, a new semi-analytical method is proposed for solving boundary value problems of 3D potential problems. In this method, the boundary of the problem domain is discretized by a set of special non-isoparametric elements. In these new elements, higher-order Chebyshev mapping functions and new special shape functions are used. The shape functions are formulated to provide Kronecker Delta property for the potential function and its derivative. Moreover, the first derivative of shape functions are assigned to zero at any given control point. Finally, using weighted residual method and implementing Clenshaw– Curtis quadrature, the coefficient matrices of equations system become diagonal, which results in a set of decoupled governing equations for the whole system. This means that the governing equation for each degree of freedom (DOF) is independent from other DOFs of the domain. Validity and accuracy of the present method are fully demonstrated through some benchmark problems

Diagonal coefficient matrices, Non-isoparametric element, Clenshaw–Curtis quadrature, Chebyshev polynomials, Potential problems