In order to consider the effects of the higher modes in the pushover analysis, during the recent years several multi-modal pushover procedures have been presented. In these methods the response of the considered modes are combined by the square-rootof-sum-of-squares (SRSS) rule while application of the elastic modal combination rules in the inelastic phases is no longer valid. In this research ...

Modal parameter extraction of high speed shafts is of critical importance in mechanical design of turbo-pumps. Due to the complex geometry and peripheral components of turbo-pumps, difficulties can arise in determination of modal parameters. In this study, modal properties of a turbo-pump shaft, was studied by experimental modal analysis, and using different excitation techniques. An innovative...

This paper comprehensively evaluates the Modal Pushover Analysis (MPA) procedure against the ‘‘exact’’ nonlinear response history analysis (RHA) and investigates the accuracy of seismic demands determined by pushover analysis using FEMA-356 force distributions; the MPA procedure in this paper contains several improvements over the original version presented in Chopra and Goel (2002). Seismic de...

This paper constructs perfectly matched layers (PML) for a system of 2D Coupled Nonlinear Schrödinger equations with mixed derivatives which arises in the modeling of gap solitons in nonlinear periodic structures with a non-separable linear part. The PML construction is performed in Laplace Fourier space via a modal analysis and can be viewed as a complex change of variables. The mixed derivati...

In this paper, a method for obtaining nonlinear sti ness coe cients in modal coordinates for geometrically nonlinear nite-element models is developed. The method requires application of a nite-element program with a geometrically nonlinear static capability. The MSC/NASTRAN code is employed for this purpose. The equations of motion of a MDOF system are formulated in modal coordinates. A set of ...

in this article the general non-symmetric parametric form of the incremental secant stiffness matrix for nonlinear analysis of solids have been investigated to present a semi analytical sensitivity analysis approach for geometric nonlinear shape optimization. to approach this aim the analytical formulas of secant stiffness matrix are presented. the models were validated and used to perform inve...

Abstract Although the identification and analysis of structures with a localized nonlinearity, either weak or strong, is within reach, multiple nonlinearities coexisting at different locations still challenge, especially if these are strong. In such cases, identifying each nonlinearity separately requires tedious work may not be possible all in some cases. this paper, an approach for experiment...

bridges, as an essential part of transportation system, play a special role in economy, politic and military all around the world. serviceability of bridges is of high importance especially in emergencies, helping injured people and proportioning transportation after earthquakes. earthquake regulation codes, normally suggest linear methods to conduct the analysis, and nonlinear analysis is bare...

an active antenna for transmitter application in s frequency band is designed and analyzed using harmonic balance technique which is based on the nonlinear model of active devices. in this active antenna, the amplifier is integrated with the radiator which is a rectangular patch antenna. this patch antenna is analyzed employing full-wave momentum method. by applying nonlinear model of transisto...