Study on the Noise Character of Excavator Based on Spectrum Method

Author(s):  
Hu Xiaodong ◽  
Gong Quanshuai ◽  
Lv Jiantao ◽  
Gong Lixiao
Keyword(s):  
2021 ◽  
pp. 107754632110075
Author(s):  
Junling Chen ◽  
Jinwei Li ◽  
Dawei Wang ◽  
Youquan Feng

The steel–concrete hybrid wind turbine tower is characterized by the concrete tubular segment at the lower part and the traditional steel tubular segment at the upper part. Because of the great change of mass and stiffness along the height of the tower at the connection of steel segment and concrete segment, its dynamic responses under seismic ground motions are significantly different from those of the traditional steel tubular wind turbine tower. Two detailed finite element models of a full steel tubular tower and a steel–concrete hybrid tower for 2.0 MW wind turbine built in the same wind farm are, respectively, developed by using the finite element software ABAQUS. The response spectrum method is applied to analyze the seismic action effects of these two towers under three different ground types. Three groups of ground motions corresponding to three ground types are used to analyze the dynamic response of the steel–concrete hybrid tower by the nonlinear time history method. The numerical results show that the seismic action effect by the response spectrum method is lower than those by the nonlinear time history method. And then it can be concluded that the response spectrum method is not suitable for calculating the seismic action effects of the steel–concrete hybrid tower directly and the time history analyses should be a necessary supplement for its seismic design. The first three modes have obvious contributions on the dynamic response of the steel–concrete hybrid tower.


Science ◽  
1929 ◽  
Vol 69 (1782) ◽  
pp. 229-229 ◽  
Author(s):  
S. Bloomenthal

2014 ◽  
Vol 536-537 ◽  
pp. 911-914
Author(s):  
Ning Yang ◽  
Xu Qian

In this paper, Von Karman random media is constructed with power spectrum method. The random media with Von Karman autocorrelation cannot be constructed in time domain but in frequency domain. So power spectrum method is utilized to solve the problem. The spectrum of random function is generated in frequency domain with random field and auto-correlation function. With inverse Fourier transformation, the Von Karman random media model is constructed. With different correlation lengths, six group of Von Karman random media are constructed.


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