Natural frequencies of RC concrete slab with opening


  • Mezgeen Sisen Ahmed Department of Civil Engineering, Duhok University, Duhok, Kurdistan Region – Iraq



Vibration, modal analysis, natural frequency, openings, RC slab.


Vibration analysis of plates with openings represents an important issue in civil, aerospace, and mechanical engineering applications. It has been familiar that the opening or cut-out may be considered as a defect in most cases, which generally leads to a decrease in the stiffness of the member, according to the opening’s size, shape as well as location. Hence, it affects the dynamic properties, for instance, the natural frequencies and the mode shapes. In this work, numerical modal analysis of fixed ends supported RC concrete slabs with three different aspect ratios as well as two different central square and circular openings has been investigated. The study is based on evaluating the natural frequency of these cases, as a global parameter.  A simulation process for the modal analysis using ANSYS software is done to compare the results. The natural frequencies of RC concrete slab with openings have been evaluated and compared with each other as well as with the intact slab, as control ones.  The results showed that both two shapes of central openings have an impact on the natural frequencies of the slab depending on sizes and aspect ratios.


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How to Cite

Sisen Ahmed , M. (2024). Natural frequencies of RC concrete slab with opening. Academic Journal of Nawroz University, 13(2), 603–613.