the complete 3d nonlinear dynamic problem of extensible, flexible risers conveying fluid is considered. for describing the dynamics of the system, the newtonian derivation procedure is followed. the velocity field inside the pipe formulated using hydrostatic and bernoulli equations. the hydrodynamic effects of external fluids are taken into consideration through the nonlinear drag forces in var...

In this paper, the effect of the crack on dynamic behavior of cracked micro-beam in the presence of DC and AC loads are investigated. By applying the residual axial stress and fringing field stress, a nonlinear analytical model of cracked micro-beam is presented and crack is modeled by a massless rotational spring. The governing equation of the system is solved using Galerkin procedure and shoo...

Response modification factor (R factor) is one of the seismic design parameters to be considered in evaluating the performance of buildings during strong motions. This paper has tried to evaluate the response modification factor of concrete coupled shear wall structures with various length/depth ratios of spandrel beams. The effect of diagonal reinforcement of spandrel beam was also evaluated o...

The Sirri jacket offshore platform was designed and installed in Persian gulf of Iran in 1975 and has been in service since that time. The importance of offshore structure's stability and the failure of this kind of structure during an earthquake in different active zones revealed that earthquake loading has to be considered. In this paper, Magnetorheological (MR) fluid dampers have been propos...

demand response (dr) has many beneficiaries in the electricity market. there are independent players who are interested in dr, which include: transmission system owners, distributors, retailers, and aggregators. in this paper dr is introduced as a tradable commodity that can be exchanged between dr buyers and sellers in a pool-based market which is called demand response exchange (drx). drx ope...

seismic base isolation are devices that used to limit the human and material damage caused by an earthquake. this devices diffuse the energy induced at the time of the earthquake before being transferred to the structure.the base isolated structures when subjected to the near-fault eathquakes which contain long-period velocity pulses that may coincide with the period of base isolated structures...

there are different methods to reduce drag in high speed hulls. one of these methods is a change in the shape of the body by adding longitudinal side tunnels. in this paper it has been attempted to determine the influence of the tunnel height on hydrodynamic characteristics of the hull to achieving an optimum shape for the tunnel. to achieve this purpose, numerical simulation of the problem has...

Dampers can reduce structural response under dynamic loads. Since dampers are costly, the design of structures equipped with dampers should make their application economically justifiable. Among the effective cost reduction factors is optimal damper placement. Hence, this study intended to find the optimal viscous damper placement using efficient optimization methods. Taking into account the no...