To reduce the damages of aeolian vibration of conductors to the power transmission networks, the most common method is installation of Stock-bridge dampers. Estimation of the damper’s dissipated energy is an important factor in determining the number and location of installation of these types of vibration absorbers. This estimation is strongly dependent upon the assumed mode shape of the condu...

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...

This paper describes a new model-based segmentation technique combining desirable properties of physical models (snakes, 2]), shape representation by Fourier parametrization (Fourier snakes, 12]), and modelling of natural shape variability (eigenmodes, 7, 10]). Flexible shape models are represented by a parameter vector describing the mean contour and by a set of eigenmodes of the parameters ch...

investigating downstream changes in bed load shape can be useful to detect watershedhydrological processes and it is very important to design hydraulic structures and to managecapacity of large storage dams, properly. regarding to doing of enforcement studies, thisresearch was conducted in qalesar river in upstream of chahardangeh watershed in mazandaranprovince. after recognition of the study ...

In this paper, a two-stage method for damage detection and estimation in tall shear frames is presented. This method is based on the first mode shape of a shear frame. We demonstrate that the first mode shape slope is very sensitive to the story stiffness. Thus, at the first stage, by using the grey system theory on the first mode shape slope, damage locations are identified in shear frames. Da...

For optimization of real-world arch dams, it is unavoidable to consider two or more conflicting objectives. This paper employs two multi-objective differential evolution algorithms (MoDE) in combination of a parallel working MATLAB-APDL code to obtain a set of Pareto solutions for optimal shape of arch dams. Full dam-reservoir interaction subjected to seismic loading is considered. A benchmark ...

In this paper dynamic damping properties of a nominated flexible structural adhesive have been identified using an extended-direct modal based joint identification method. It has been revealed that damping characteristics of adhesive are correlated to both frequency and mode shape. Young’s and shear moduli increase with frequency but damping on the other hand, decrease. The results showed that ...

it has been proved that natural frequencies are stationary at the natural modes. also it has been shown that at the first mode it is a minimum and for systems with finite number of degrees of freedom the highest frequency is maximum (reference 1 and 2). beyond these statements nothing more can be said about the behavior of the natural frequencies without defining precisely the manner in which t...