Trusses are commonly used structures and they are present in the most constructions because it use a small amount of material and for the loads they can support. The paper presents the dynamic behavior of a Warren truss with seven elements when for one member of the truss the modulus of elasticity is much different compared to the other elements. The relative frequency shift for the first seven vibration mode are calculated taking into consideration that the slenderness ratio has a constant value and the transverse section of the elements is changed. The conclusions reveal that by maintaining the constant value of a slenderness ratio, the relative frequency shift is not modified for the considered transverse sections of the elements of the Warren truss.

Keywords: Warren truss, slenderness ratio, modal analysis, relative frequency shift