Nonlinear dynamic analysis and natural frequencies of gabled frame having flexible restraints and connections

Abstract

Nonlinear dynamic and natural frequencies of a gabled frame with elastic restraints and semi-rigid connections are investigated by using a program in OpenSees software. Natural frequencies are obtained for two states, which are flexible connections and semi-rigid supports, separately. The mode shapes of structure are also obtained for the described states. Also, the effect of connection flexibility on the dynamic responses of the frame is obtained for different values of peak ground acceleration. The members of this structure are modeled as a nonlinear beam-column element. The members of structure are assumed to be prismatic. Two equal lumped masses at the head of two columns in horizontal and vertical directions are considered as the mass pattern of structure. Note that three degrees of freedom are allocated to all nodes. Furthermore, the mode shapes of frame are obtained. Conclusively, the effects of semi-rigid connections and supports on the natural frequencies and mode shapes of structure are investigated. As results, the top level displacement and base shear responses of frame are reported.

Nonlinear Resonance Analysis of Slender Portal Frames under Base Excitation

“…The next step is the solution of the nonlinear system of algebraic equations. The transformation of the equations of motion from time to frequency domain results in a nonlinear system of algebraic equations both for the linear and nonlinear cases, as shown by (6) and (19), with the unknown variables being the forcing frequency and the modal amplitudes. In this section, the technique to solve the nonlinear system of equations must consider the possibility of frequency and amplitude limit points.…”

“…In linear case, Fi(D) = K L D, and the resultant nonlinear system of equations defined by (19) is the same as the system obtained through the classical HBM (see (5)).…”

“…Gonçalves et al [18] published an experimental analysis of the nonlinear vibrations of a slender metal column under self-weight. Masoodi and Moghaddam [19] studied the nonlinear dynamics and natural frequencies of gabled frames having flexible restraints and connections. To control unwanted nonlinear phenomena and vibrations of frames, several control techniques are proposed in literature.…”

Exact natural frequencies and buckling load of functionally graded material tapered beam-columns considering semi-rigid connections

“…The connection stiffness ( R ) and ( K ) could be considered as either the initial stiffness or the secant one. In this article, the nondimensional coefficients c and c s are defined to represent the flexibility of rotational and transitional connections, respectively (Masoodi and Heyrani Moghaddam, 2015). They can be defined in an interval from zero to one.…”

Finite element formulation and analysis of a functionally graded Timoshenko beam subjected to an accelerating mass including inertial effects of the mass

“…A wide range of FGM application systems are support systems such as beams. In recent years, many scientists have studied the static and vibrational behaviour of FGM beams (Aydogdu and Taskin, 2007;Chakraborty et al, 2003;Ebrahimi et al, 2016;Eltaher et al, 2013;Jafari-Talookolaei et al, 2018;Kang and Li, 2010;Khan et al, 2016;Kim and Lee, 2014;Kosmatka, 1995;Lien et al, 2017;Mashat et al, 2014;Masoodi and Moghaddam, 2015;Murín et al, 2010;Nguyen and Nguyen, 2015;Rezaiee-Pajand and Masoodi, 2016;Rezaiee-Pajand and Rajabzadeh-Safaei, 2018;Sina et al, 2009;Taati, 2018;Taeprasartsit, 2013;Yokoyama, 1996;Zhang and Zhou, 2008). Analysis of systems subjected to moving loads, an ongoing long-standing problem, and some studies have investigated the transverse responses of the limited number of FGM beams to moving forces, in the transverse and axial directions, neglecting the effects of inertia (Kadivar and Mohebpour, 1998;Nguyen et al, 2013;Rajabi et al, 2013;Şimşek and Al-shujairi, 2017;Şimşek and Kocatürk, 2009).…”