Modal Analysis

In this paper, the pressure distribution on the slippers of a mono-rail sled with vibration damping is investigated. Due to the many applications of sled testing in the aerospace industry, the study of system vibrations is highly noticeable. In this research, first, by More

In this paper, the pressure distribution on the slippers of a mono-rail sled with vibration damping is investigated. Due to the many applications of sled testing in the aerospace industry, the study of system vibrations is highly noticeable. In this research, first, by mathematical modelling of the sled, the governing Equations are extracted and natural frequencies and vibration modes are obtained from the analytical method using the mass and stiffness matrix of the system. Then, using numerical simulation and validation methods with experimental results performed in wind tunnels, the modal analysis of the designed sled sample is performed. A difference of less than eight percent in both numerical and analytical methods proves the accuracy of the results. The results show that the role of the slipper in the vibrations created in the sled is very important due to the large torsional and transverse oscillations in different positions, and the highest static pressure occurs in the inner layer of the slipper. Manuscript profile

Open Access Article

8 - Numerical and Experimental Investigation on the Effect of Geometric Discontinuity on Frequency Response of Composite Lattice Conical Structures
M. R Zamani M Zaretabar

10.22034/jsm.2021.1927323.1689

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Open Access Article

9 - Noise Effects on Modal Parameters Extraction of Horizontal Tailplane by Singular Value Decomposition Method Based on Output Only Modal Analysis
P Jalali S Varahram R Hassannejad M.H Sadeghi

10.22034/jsm.2019.666809

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Open Access Article

10 - Thermal and Mechanical Properties of Hybrid Composite Strengthened by Carbon Fibers/Aramid Fibers
F Basati M.H Yas

10.22034/jsm.2023.1977242.1762

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Open Access Article

11 - A Simple Finite Element Procedure for Free Vibration and Buckling Analysis of Cracked Beam-Like Structures
M.R Shirazizadeh H Shahverdi A Imam

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Open Access Article

12 - The study of the vibration of the floating structure due to the excitation of the propeller using numerical analysis of fluid-structure (FSI)
Mahdiesadat Azizai Yousef Amirian Abdolhossein Fereidoon

Vibration of floating structures under the effect of propeller excitation is One of the main issues in the design of floating structures and not paying attention to this issue and the placement Super structure at the bottom of the float, vibrations caused by the stimulu More

Vibration of floating structures under the effect of propeller excitation is One of the main issues in the design of floating structures and not paying attention to this issue and the placement Super structure at the bottom of the float, vibrations caused by the stimulus of the fan can cause problems for crews and individuals and the vibrations from the propeller make noise and also reduce the life of existing machines in the bottom of the float. In this paper the vibrations caused by the propeller stimulation, using a numerical analysis of fluid-structure on a commercial vessel is studied and the results are discussed. First with respect to the geometry and condition a suitable propeller was chosen for the float and the numerical solution for different speeds of the float and the angular velocity of the impeller is done. The floating structure is designed based on the standard and discretization is conducted using finite element.  Pressure distribution on the propeller and hull obtained from the numerical solution of fluid flow, has been applied to floating structures in the structural analysis and floating structures due to harmonic loading induced by the rotation of the propeller is investigated and modal analysis of floating structures has been performed And the results of its analysis in a frequency range including natural frequencies that canaries in different modes and rotational speeds  of the propeller were recorded. The Results show that in some rotational speeds of the propeller excitation frequency in rotational speed can lead to vibration increase and resonance amplitude The results are compared with the standard range, the results show that with accurate choosing of the propeller And the range of allowable angular velocity and optimization of the structure, we can provide the Requirements for vibration exposure in the limited range. Manuscript profile

Open Access Article

13 - A Comparison of Modal Analysis of Ritz Vector Mode (Ritze) and Eagan Vector (Eigen) based on nonlinear Time History (NTH) Dynamic Analysis
seyed ali mousavi davoudi Morteza Naghipour

Nowadays, the requirements of designing structures based on low weight and high strength in structural engineering science, have increased the possibility of unwanted and destructive vibrations in these systems. Also, using of computer softwares for modeling alone canno More

Nowadays, the requirements of designing structures based on low weight and high strength in structural engineering science, have increased the possibility of unwanted and destructive vibrations in these systems. Also, using of computer softwares for modeling alone cannot accurately predict the dynamic behavior of structures. For this reason, a fundamental approach to experimental techniques was developed and made progress in the field of modal analysis. In recent years, modal analysis has been applied as a tool to determine and enhance the dynamic properties of structures. The vibrational modes obtained from the modal analysis, are useful for understanding the behavior of the structure correctly. Modal analysis is also used in modal time history analyzes and quasi-dynamic analysis of response spectrum. An important point in modal analysis is that when using modal analysis there are two types of analytical models named special vector state and Ritz vector state. Finding the best method for modal analysis of structural responses is very important in modal analysis, so far no comprehensive studies have been conducted to date. Considering the importance of this issue, in this study the evaluation of the accuracy between the two modes of vectors (Ritz) and (Eigen) in modal analysis is done. It is concluded that the modal analysis of Eigen vector is more accurate than Ritz vector and the results of Eigen modal              analysis are closer to reality. Manuscript profile

Open Access Article

14 - A Survey of structural behavior and Stability of Davazdah Emam Dome in Yazd Against Earthquake
Mostafa AttarAbassi saied hematzadeh gorban mahbobi

This paper aims to analyze the sustainability and vulnerability of Davazdah Emam Dome that is located in the historical context of Yazd city against to Earthquake. This dome dated back to Al-Muzaffar era (429 A.H.) and it is the oldest monument with inscription in Yazd. More

This paper aims to analyze the sustainability and vulnerability of Davazdah Emam Dome that is located in the historical context of Yazd city against to Earthquake. This dome dated back to Al-Muzaffar era (429 A.H.) and it is the oldest monument with inscription in Yazd. Baked bricks and traditional materials are used to build this dome. In this paper a 3D modeling of dome was made in AutoCAD and carried out its structural analysis in Ansys software. After its structural analysis under own weight and modal analysis and earthquake analysis (Naghan area), we surveys the results and identify the vulnerable and sensitive areas of dome with lowest cost and in a short time. Also the structural characteristics of dome are specified. Manuscript profile

Open Access Article

15 - ارتعاشات صفحه ترک خورده با استفاده از روش quadrature دیفرانسیل و تجزیه و تحلیل مد تجربی
س. مرادی پ. علیموری

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Open Access Article

16 - مدل‌سازی و تحلیل مودال برای نوسانات تیر IPMCو شبیه‌سازی به عنوان عملگر
آرش رجایی علی مختاریان مصطفی پیرمرادیان

هدف این مقاله تحلیل مودال تیر از جنس پلیمر-یونی فلزی است، سپس سیستم را به یک مود با پارامترهای منحصربهفرد خود خلاصه کرده تا در شبیه سازی عملگر به ما کمک کند. در این مقاله ابتدا با استفاده از تحلیل ریاضی و فرم بسته تابع تبدیل سیستم تیر یکسر گیردار، پاسخ دینامیکی آن More

هدف این مقاله تحلیل مودال تیر از جنس پلیمر-یونی فلزی است، سپس سیستم را به یک مود با پارامترهای منحصربهفرد خود خلاصه کرده تا در شبیه سازی عملگر به ما کمک کند. در این مقاله ابتدا با استفاده از تحلیل ریاضی و فرم بسته تابع تبدیل سیستم تیر یکسر گیردار، پاسخ دینامیکی آن را به نیروهای ورودی مختلف (متمرکز و پیوسته) محاسبه کرده و برای انواع مختلف سیستم، نقاط تشدید و ضدتشدید را در تحلیل فرکانسی پیدا میشود، سپس با استفاده از آنالیز مودال در سیستم، کل پاسخ آنرا در مود پایه خلاصه کرده و پارامترهای فرکانس طبیعی نامیرا و ضریب میرایی در این مود برای سیستم معرفی میشود، سپس تیر یکسرگیردار کامپوزیتی را به عنوان یک عملگر در نظر گرفته میشود که با ولتاژ ورودی، تغییر مکان و نیرو در سر آزاد خود ایجاد میکند که با بررسی پاسخها به ورودیها، رفتار سیستم تحلیل میشود Manuscript profile

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