دانلود رایگان مقالات عمران و معماری

Electromechanical Finite Element Modeling of Unstiffened Smart Steel Shear Walls (SSSWs)

کریم عابدي- محمد رضا چناقلو- مهرات ابراهیمیان- یاسر شهبازي- , 5th National Congress on Civil EngineeringSteel shear walls (SSWs) are constructed in two forms of unstiffened and stiffened forms. The unstiffened form is the best passive choice for designers, because of its simple constructional details and lower cost. The behaviour of thin steel plates, which are adequately supported along their boundaries and are subjected to shear loading, is stable in the post- buckling domain. In this research, electromechanical finite element modeling of unstiffened smart steel shear walls (SSSWs) is investigated. The SSSWs are made of elastic host part and piezoelectric active layers. The theoretical model of SSSWs is a three-layer plate that accomplishes as both an extension or shear actuation mechanisms and a load-carrying system. In the one hand, the extension actuator consists of an elastic core, sandwiched between two piezoelectric active outer covering layers. The piezoelectric layers are polarized transversely, i.e., the polarization vector is parallel to the applied electric field intensity vector. On the other hand, the shear actuator consists of two elastic layers, sandwiched one piezoelectric active layer. The piezoelectric layer is polarized transversely, i.e., the polarization vector is perpendicular to the applied electric field intensity vector.The corresponding electromechanical finite element modeling is coded and calculated using ANSYS®. In this approach, the piezoelectric pieces of SSSWs are used in three forms: (1) horizontal (2) vertical and (3) inclined to the diagonal direction of steel plate. In the third case, the piezoelectric segments take place parallel to the tension field of plate which happens after buckling. This new combination of passive steel shear walls (SSWs) with smart piezoelectric segments (SSSWs) can be imaged as combination of SSWs with diagonal piezoelectric braces. Load bearing capacity of plate will be increased after post-buckling when an electric field intensity vector is applied. However, because of the appearance of the dielectric breakdown phenomena, any arbitrary electric field intensity can not been applied to the piezoelectric layers. These phenomena depend directly on the geometry of the piezoelectric layers. The efficiency of SSSWs is determined in one bay portal frame under pushover static shear