the ambient vibration measurement is a kind of output data-only dynamic testing where the traffics and winds are used as agents responsible for natural or environmental excitation. therefore an experimental modal analysis procedure for ambient vibration testing needs to base itself on output-only data. the modal analysis involving output-only measurements present a challenge that requires the u...

The present study set out to investigate the effect of teaching substitution as a kind of grammatical cohesion on the true identification of confusing substitution elements with cohesive or non-cohesive roles in different contexts and also the production of modal, reporting and conditional contexts through clausal substitution acquaintance. To this end, the following procedures were taken. Firs...

this study contains the identification of modal dynamic properties of a 3-story large-scale steel test frame structure through shaking table measurements. shaking table test is carried out to estimate the modal properties of the test frame such as natural frequencies, damping ratios and mode shapes. among many different model structures, arx (auto recursive exogenous) model structure is used fo...

During a revisit to modal identification in the past three decades, an overview of the major developments and issues in modal identification is motivated. A brief review on the progress from Single-Input/Single-Output (SISO), Single-Input/Multi-Output (SIMO) to Multi-Input/Multi-Output (MIMO) identification in frequency, time and spatial domain, is presented. The latest developments and issues ...

According to the great importance of safety in aerospace industries, identification of dynamic parameters of related equipment by experimental tests in operating conditions has been in focus. Due to the existence of noise sources in these conditions the probability of fault occurrence may increases. This study investigates the effects of noise in the process of modal parameters identification b...

identification of damping parameter is usually more complicated and unreliable comparing to mass or stiffness identification in structural dynamics. there are many factors such as intermolecular friction, coulomb friction and viscous damping affecting the damping mechanisms in a structure. therefore it is difficult, and in some cases impossible, to describe the details of damping mechanisms by ...

Crack identification is a very important issue in mechanical systems, because it is a damage that if develops may cause catastrophic failure. In the first part of this research, modal analysis of a multi-cracked variable cross-section beam is done using finite element method. Then, the obtained results are validated usingthe results of experimental modal analysis tests. In the next part, a nove...

crack identification is a very important issue in mechanical systems, because it is a damage that if develops may cause catastrophic failure. in the first part of this research, modal analysis of a multi-cracked variable cross-section beam is done using finite element method. then, the obtained results are validated usingthe results of experimental modal analysis tests. in the next part, a nove...