Ehsan Noroozinejad Farsangi^1,*, Aleksandra Bogdanovic², Zoran Rakicevic², Angela Poposka², Marta Stojmanovska²

Structural Durability & Health Monitoring, Vol.14, No.4, pp. 283-301, 2020, DOI:10.32604/sdhm.2020.010564

Abstract In this study, the methodology and results of ambient vibration-based investigations of the historical Tash Mosque in Kosovo and a 3-story historical building in Bulgaria are presented. The investigations include full-scale in situ testing of both structures due to ambient vibrations induced by micro-seismic, wind, traffic, and other human activities. To this aim, Ranger seismometers and Kinemetric products were used. Measurements were performed in both horizontal directions in several points along the structures’ height utilizing a high-speed data acquisition device. All recorded data have been analyzed and processed by the software developed at IZIIS, and then the processed data were… More >

Ajay Veludurthi¹, Venkateshwarlu Bolleddu^2,*

Energy Engineering, Vol.117, No.2, pp. 49-61, 2020, DOI:10.32604/EE.2020.010666

Abstract This work focused on modal and harmonic analysis of small wind turbine blades taken from the NACA 63415 series. The sandwich structure type composite blade is fabricated from GFRP and epoxy with Uni-vinyl hard foams of different alignments as stiffeners. In this work, the modal and harmonic analysis of different varieties of blades like solid, hallow and rectangular alignment blades is carried out by the finite element method using ANSYS 18.1 software. From Finite Element Analysis, the natural frequencies, amplitudes and mode shapes are obtained. Based on the working principle of wind turbine blades, the boundary conditions are applied. The… More >

Gouravaraju Saipraneeth¹, Ranjan Ganguli²

Structural Durability & Health Monitoring, Vol.7, No.1&2, pp. 23-64, 2011, DOI:10.3970/sdhm.2011.007.023

Abstract In this paper, the effect of damage on mode shape related parameters of a beam is investigated. The damage is represented by a localized reduction in beam stiffness. The damage location and amount is varied using a finite element model of the beam to obtain the mode shapes. A beam which is simply supported at both ends is used for the numerical results. The periodic nature of the beam is exploited to obtain spatial Fourier coefficients of the mode shapes. As the damage location and size are varied, it is found that the Fourier coefficients also change and are found… More >

Anders Brandt¹, Marta Berardengo², Stefano Manzoni³, Marcello Vanali², Alfredo Cigada³

Sound & Vibration, Vol.52, No.3, pp. 18-22, 2018, DOI:10.32604/sv.2018.03872

Abstract Methods for scaling mode shapes determined by operational modal analysis (OMA) have been extensively investigated in the last years. A recent addition to the range of methods for scaling OMA mode shapes is the so-called OMAH technique, which is based on exciting the structure by harmonic forces applied by an actuator. By applying harmonic forces in at least one degree-of-freedom (DOF), and measuring the response in at least one response DOF, while using at least as many frequencies as the number of mode shapes to be scaled, the mode shape scaling (modal mass) of all modes of interest may be… More >

Kanchi Venkatesulu Reddy¹, Ranjan Ganguli²

CMC-Computers, Materials & Continua, Vol.5, No.2, pp. 79-98, 2007, DOI:10.3970/cmc.2007.005.079

Abstract This paper investigates the effect of damage on beams with fixed boundary conditions using Fourier analysis of the mode shapes in spatial domain. A finite element model is used to obtain the mode shapes of a damaged fixed-fixed beam. Then the damaged beams are studied using a spatial Fourier analysis. This approach contrasts with the typical time domain application of Fourier analysis for vibration problems. It is found that damage causes considerable change in the Fourier coefficients of the mode shapes. The Fourier coefficients, especially the higher harmonics, are found to be sensitive to both damage size and location and… More >