scholarly journals Iterative Dummy Area Method for the Improvement of CGH Reconstruction using Angler Spectrum Method

2018 ◽  
Author(s):  
Yusei Uezono ◽  
Koki Nakashima ◽  
Shiyuan Yang
Keyword(s):  
Area Method ◽  
Spectrum Method

Seismic response analysis of steel–concrete hybrid wind turbine tower

2021 ◽  
pp. 107754632110075
Author(s):  
Junling Chen ◽  
Jinwei Li ◽  
Dawei Wang ◽  
Youquan Feng
Keyword(s):  
Wind Turbine ◽  
Response Spectrum ◽  
Ground Motions ◽  
Time History ◽  
Seismic Action ◽  
Response Spectrum Method ◽  
Spectrum Method ◽  
Wind Turbine Tower ◽  
Ground Types ◽  
Nonlinear Time History

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.

scholarly journals An experimental method to determine the intralaminar fracture toughness of high-strength carbon-fibre reinforced composite aerostructures

2018 ◽  
Vol 122 (1255) ◽  
pp. 1352-1370 ◽  
Author(s):  
H. Liu ◽  
B.G. Falzon ◽  
G. Catalanotti ◽  
W. Tan
Keyword(s):  
Fracture Toughness ◽  
Tensile Strength ◽  
Crack Tip ◽  
Damage Mechanism ◽  
Calibration Method ◽  
Compact Tension ◽  
Tensile Fracture ◽  
High Tensile Strength ◽  
Physical Test ◽  
Area Method

ABSTRACTCarbon fibres with high tensile strength are being increasingly utilised in the manufacture of advanced composite aerostructures. A Modified Compact Tension (MCT) specimen is often deployed to measure the longitudinal intralaminar fracture toughness but a high tensile strength often leads to premature damage away from the crack tip. We present an approach whereby the MCT specimen is supported by external fixtures to prevent premature damage. In addition, we have developed a novel measurement technique, based on the fibre failure strain and C-scanning, to determine the crack length in the presence of surface sublaminate delamination which masks the crack tip location. A set of cross-ply specimens, with a ((90/0)s)4 layup, were manufactured from an IMS60/epoxy composite system Two different data reduction schemes, compliance calibration and the area method, are used to determine the fibre-dominated initiation and propagation intralaminar fracture toughness values. Propagation values of fracture toughness were measured at 774.9 ± 5.2% kJ/m2 and 768.5 ± 4.1% kJ/m2, when using the compliance calibration method and the area method, respectively. Scanning Electron Microscopy (SEM) is carried out on the fracture surface to obtain insight into the damage mechanism of high-tensile-strength fibre-reinforced unidirectional composites. The measured tensile fracture toughness value is used in a fully validated computational model to simulate the physical test.

The Mathematical Model of Welding Process Comparative Study of Identification Method

2012 ◽  
Vol 472-475 ◽  
pp. 2241-2244 ◽  
Author(s):  
Jun Feng Wu ◽  
Jing Huang
Keyword(s):  
Weld Pool ◽  
Academic Research ◽  
Welding Process ◽  
Least Square Method ◽  
Mathematic Model ◽  
Least Square ◽  
Complex Object ◽  
Strong Nonlinearity ◽  
Area Method ◽  
Pulsed Gtaw

The dynamic process of the weld pool is a high complex object with strong nonlinearity, mult-variable coupling and a mount of stochastic and uncertain factors. It is very difficult to obtain an analysis mathematic model of weld pool dynamics. Pulsed Gas Tungsten Arc Welding (GTAW) is an important metal’s welding technology, which has been widely applied in the aerospace and manufacturing areas. Therefore, the dynamic characteristic of the welding process has always been hot and difficult in the field of academic research and engineering applications. In order to solve the difficulties of modeling and controlling of nonlinear system, this paper investigates the dynamic characters of the pulsed GTAW from the classic control systems. It obtains the SISO transfer function model by the area method and least square method. The results of simulation experiment show that the area method is better between the two methods.

Quantification of mitral regurgitation by colour flow Doppler imaging — value of the ‘proximal isovelocity surface area’ method

1993 ◽  
Vol 42 (2) ◽  
pp. 165-173 ◽  
Author(s):  
Georg Grossmann ◽  
Martin Giesler ◽  
Arnold Schmidt ◽  
Matthias Kochs ◽  
Siegfried Wieshammer ◽  
...  
Keyword(s):  
Mitral Regurgitation ◽  
Surface Area ◽  
Doppler Imaging ◽  
Area Method ◽  
Proximal Isovelocity Surface Area ◽  
Colour Flow
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