The dynamic stability of a rotating pre-twisted asymmetric cross-section Timoshenko beam subjected to lateral parametric excitation

2006 ◽  
Vol 48 (8) ◽  
pp. 878-888 ◽  
Author(s):  
Mustafa Sabuncu ◽  
Kaan Evran
Keyword(s):  
Dynamic Stability ◽  
Cross Section ◽  
Timoshenko Beam ◽  
Parametric Excitation

scholarly journals Analysis of Timoshenko beam with Koch snowflake cross-section and variable properties in different boundary conditions using finite element method

2021 ◽  
Vol 13 (11) ◽  
pp. 168781402110609
Author(s):  
Hossein Talebi Rostami ◽  
Maryam Fallah Najafabadi ◽  
Davood Domiri Ganji
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Boundary Conditions ◽  
Natural Frequency ◽  
Cross Section ◽  
Timoshenko Beam ◽  
Natural Frequencies ◽  
Variable Properties ◽  
The Third ◽  
Koch Snowflake

This study analyzed a Timoshenko beam with Koch snowflake cross-section in different boundary conditions and for variable properties. The equation of motion was solved by the finite element method and verified by Solidworks simulation in a way that the maximum error was about 2.9% for natural frequencies. Displacement and natural frequency for each case presented and compared to other cases. Significant research achievements illustrate that if we change the Koch snowflake cross-section of the beam from the first iteration to the second, the area and moment of inertia will increase, and we have a 5.2% rise in the first natural frequency. Similarly, by changing the cross-section from the second iteration to the third, a 10.2% growth is observed. Also, the hollow cross-section is considered, which can enlarge the natural frequency by about 26.37% compared to a solid one. Moreover, all the clamped-clamped, hinged-hinged, clamped-free, and free-free boundary conditions have the highest natural frequency for the Timoshenko beam with the third iteration of the Koch snowflake cross-section in solid mode. Finally, examining important physical parameters demonstrates that variable density from a minimum value to the standard value along the beam increases the natural frequencies, while variable elastic modulus decreases it.

Influence of Shape of Coarse Aggregate on Performance of Open Graded Friction Course

2011 ◽  
Vol 239-242 ◽  
pp. 3266-3274
Author(s):  
Jin Xi Zhang ◽  
Chao Wang
Keyword(s):  
Wear Resistance ◽  
Bulk Density ◽  
Dynamic Stability ◽  
Cross Section ◽  
Coarse Aggregate ◽  
Void Content ◽  
Horizontal Cross Section ◽  
Important Material ◽  
Large Bulk ◽  
Open Graded Friction Course

As a new kind of pavement material, the Open Graded Friction Course (called OGFC) has many advantages, and so is rapidly popularized in China recently. However, the performance of OGFC decreases with the utilization of road, such as the decrease in permeability, durability and so on. In the present study, the influence of the shape of coarse aggregate, which is the most important material in OGFC, on the performance of OGFC was investigated in laboratory. The shape of coarse aggregate is indicated by the bulk density and total 4 kinds of aggregates with different bulk density were produced artificially and tested in this study. When the shape of coarse aggregate changed, the wear resistance and dynamic stability of OGFC also changed lightly. The bulk density of aggregate has no serious influence on the void content, but has obvious influence on the permeability of OGFC. The shape of continuous void in horizontal cross-section becomes rounder when the aggregate with large bulk density is used. The rounder continuous void is benefit for the flowing of water, so the permeability of OGFC is improved.

Analytical Treatment of In-Plane Parametrically Excited Undamped Vibrations of Simply Supported Parabolic Arches

2003 ◽  
Vol 125 (1) ◽  
pp. 73-79 ◽  
Author(s):  
Dimitris S. Sophianopoulos ◽  
George T. Michaltsos
Keyword(s):  
Differential Equations ◽  
Free Vibration ◽  
Dynamic Stability ◽  
Parametric Excitation ◽  
Stability Problem ◽  
Axial Loading ◽  
Time Dependent ◽  
Analytical Treatment ◽  
Simply Supported ◽  
Forced Motion

The present work offers a simple and efficient analytical treatment of the in-plane undamped vibrations of simply supported parabolic arches under parametric excitation. After thoroughly dealing with the free vibration characteristics of the structure dealt with, the differential equations of the forced motion caused by a time dependent axial loading of the form P=P0+Pt cos θt are reduced to a set of Mathieu-Hill type equations. These may be thereafter tackled and the dynamic stability problem comprehensively discussed. An illustrative example based on Bolotin’s approach produces results validating the proposed method.

Sign in / Sign up

Export Citation Format

Share Document