When a pipe bend is modelled with straight beam elements, its stiffness, particularly in bending behavior, is overestimated than its true value. In this paper, we propose a simple and practical beam-modelling technique to estimate its stiffness properly. When this technique, based on the strain energy concept, is employed to modify the beam sectional properties of the bend, quite satisfactory results can be obtained. To verify the validity of this method, we apply the present technique to the free vibration analysis of a center pipe with 2 bends, one of the three components of the automobile exhaust system.