Natural frequencies of multi-irregular span beams under elastic supports by modal analysis method
Other Title(s)
الترددات الطبيعية للعتبات الغير منتظمة الفضوة المتعددة تحت إسناد مرن باستخدام التحليل الشكلي
Joint Authors
Jweeg, Muhsin Jabr
Ismail, Mahmud Rashid
Source
Nahrain University-College of Engineering Journal
Issue
Vol. 19, Issue 2 (31 Dec. 2016), pp.353-362, 10 p.
Publisher
Nahrain University College of Engineering
Publication Date
2016-12-31
Country of Publication
Iraq
No. of Pages
10
Main Subjects
Engineering & Technology Sciences (Multidisciplinary)
Abstract EN
Evaluating the natural frequencies of multi- span beams with elastic supports play a major role in vibration designing and optimizing of many structures such as bridges, railways ,pipes and so on The continuity of the boundary conditions ,state space and numerical methods are normally used to investigate the vibration characteristics of such structures .Unfortunately ,such methods lead to high size matrix in dealing with the boundary value problem as the number of spans increase.
In the present work, the problem is solved analytically by using Modal Analysis techniques in which the continuous system is discreteized to finite degree of freedoms in terms of the generalized coordinates A proper shape function are employed for describing the system dynamical behavior and satisfying the boundary conditions .In the present method the size of the resulting Eigen matrix depends on the number of mode chosen regardless of the number of spans.
With this method wide variety of support configurations can be treated.
The validly and convergence of the present method for calculating the natural frequencies is carefully checked by comparing with the exact values for two-span beams with different boundary conditions .
It is found that using only (5) modes for the assumed solution gives only 2% error for two span simply supported and free ends beam , however for clamped ends the error is 8% .The present method is further checked by comparing with the Finite Element method the results show good agreements where the error is not increases 1% .The results of the natural frequencies of up to (10) equal and unequal spans beams under different boundary conditions and support stiffness are presented .The results showed that the natural frequencies can be highly controlled by proper choosing of the structure parameters and support stiffness.
American Psychological Association (APA)
Ismail, Mahmud Rashid& Jweeg, Muhsin Jabr. 2016. Natural frequencies of multi-irregular span beams under elastic supports by modal analysis method. Nahrain University-College of Engineering Journal،Vol. 19, no. 2, pp.353-362.
https://search.emarefa.net/detail/BIM-819166
Modern Language Association (MLA)
Ismail, Mahmud Rashid& Jweeg, Muhsin Jabr. Natural frequencies of multi-irregular span beams under elastic supports by modal analysis method. Nahrain University-College of Engineering Journal Vol. 19, no. 2 (Dec. 2016), pp.353-362.
https://search.emarefa.net/detail/BIM-819166
American Medical Association (AMA)
Ismail, Mahmud Rashid& Jweeg, Muhsin Jabr. Natural frequencies of multi-irregular span beams under elastic supports by modal analysis method. Nahrain University-College of Engineering Journal. 2016. Vol. 19, no. 2, pp.353-362.
https://search.emarefa.net/detail/BIM-819166
Data Type
Journal Articles
Language
English
Notes
Record ID
BIM-819166