Dynamic stability of a rotating pre-twisted asymmetric cross-section Timoshenko beam subjected to an axial periodic force

2006 ◽  
Vol 48 (6) ◽  
pp. 579-590 ◽  
Author(s):  
Mustafa Sabuncu ◽  
Kaan Evran
2021 ◽  
Vol 13 (11) ◽  
pp. 168781402110609
Author(s):  
Hossein Talebi Rostami ◽  
Maryam Fallah Najafabadi ◽  
Davood Domiri Ganji

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.


2011 ◽  
Vol 239-242 ◽  
pp. 3266-3274
Author(s):  
Jin Xi Zhang ◽  
Chao Wang

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.


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