FFT-based spectral element analysis for the linear continuum dynamic systems subjected to arbitrary initial conditions by using the pseudo-force method

2007 ◽  
Vol 74 (1) ◽  
pp. 159-174 ◽  
Author(s):  
Usik Lee ◽  
Jooyong Cho
Keyword(s):  
Dynamic Systems ◽  
Initial Conditions ◽  
Spectral Element ◽  
Element Analysis ◽  
Force Method

Dynamic Response of the Spectral Element Model by Using the FFT

2007 ◽  
Vol 345-346 ◽  
pp. 845-848
Author(s):  
Joo Yong Cho ◽  
Han Suk Go ◽  
Usik Lee
Keyword(s):  
Fourier Transforms ◽  
Initial Conditions ◽  
Element Model ◽  
Spectral Element ◽  
Dynamic Responses ◽  
Analysis Method ◽  
Euler Beam ◽  
Exact Analytical Solutions ◽  
Simply Supported ◽  
Spectral Analysis Method

In this paper, a fast Fourier transforms (FFT)-based spectral analysis method (SAM) is proposed for the dynamic analysis of spectral element models subjected to the non-zero initial conditions. To evaluate the proposed SAM, the spectral element model for the simply supported Bernoulli-Euler beam is considered as an example problem. The accuracy of the proposed SAM is evaluated by comparing the dynamic responses obtained by SAM with the exact analytical solutions.

Spectral element analysis for an axially moving viscoelastic beam

2004 ◽  
Vol 18 (7) ◽  
pp. 1159-1168 ◽  
Author(s):  
Hyungmi Oh ◽  
Jooyong Cho ◽  
Usik Lee
Keyword(s):  
Spectral Element ◽  
Viscoelastic Beam ◽  
Element Analysis ◽  
Axially Moving

Transient elastodynamic analysis with a combination of convolution quadrature method and pseudo-initial condition method

2018 ◽  
Vol 36 (1) ◽  
pp. 334-355
Author(s):  
Yuan Li ◽  
J. Zhang ◽  
Yudong Zhong ◽  
Xiaomin Shu ◽  
Yunqiao Dong
Keyword(s):  
Initial Conditions ◽  
Initial Condition ◽  
Quadrature Method ◽  
Memory Requirement ◽  
Content Type ◽  
Convolution Quadrature ◽  
Force Method ◽  
Cpu Time ◽  
Condition Method ◽  
Convolution Quadrature Method

Purpose The Convolution Quadrature Method (CQM) has been widely applied to solve transient elastodynamic problems because of its stability and generality. However, the CQM suffers from the problems of huge memory requirement in case of direct implementation in time domain or CPU time in case of its reformulation in Laplace domain. The purpose of this paper is to combine the CQM with the pseudo-initial condition method (PICM) to achieve a good balance between memory requirement and CPU time. Design/methodology/approach The combined methods first subdivide the whole analysis into a few sub-analyses, which is dealt with the PICM, namely, the results obtained by previous sub-analysis are used as the initial conditions for the next sub-analysis. In each sub-analysis, the time interval is further discretized into a number of sub-steps and dealt with the CQM. For non-zero initial conditions, the pseudo-force method is used to transform them into equivalent body forces. The boundary face method is employed in the numerical implementation. Three examples are analyzed. Results are compared with analytical solutions or FEM results and the results of reformulated CQM. Findings Results demonstrate that the computation time and the storage requirement can be reduced significantly as compared to the CQM, by using the combined approach. Originality/value The combined methods can be successfully applied to the problems of long-time dynamic response, which requires a large amount of computer memory when CQM is applied, while preserving the CQM stability. If the number of time steps is high, then the accuracy of the proposed approach can be deteriorated because of the pseudo-force method.

Finite Element Modeling of Processes in Optoelectronic Alignment

2001 ◽  
Author(s):  
Ben Ting ◽  
Vincent P. Manno
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Semiconductor Lasers ◽  
Initial Conditions ◽  
Laser Energy ◽  
Effective Means ◽  
Control Technique ◽  
Optical Source ◽  
Element Analysis ◽  
Mechanical Coupling

Abstract For semiconductor lasers, fiber and optical source alignment is crucial for maintaining high optical transfer efficiency. Traditional optoelectronic manufacturing, production of butterfly packages for example, involves laser welding of fiber mountings followed by a tedious realignment procedure to reverse thermally-induced distortions. An alternate technique, laser hammering, entails manipulation of the fiber to light alignment through deformation of the fiber housing with high precision laser beams. A detailed understanding of the material and mechanical behavior, characteristics, and dynamic response is vital to successfully apply an efficient controller that can choose an optimal weld pattern based on a light to fiber misalignment. Modeling provides an effective means to determine an optimal fiber alignment control technique. Modeling is difficult due to the dynamic thermal-mechanical coupling of these processes. This paper presents the preliminary results of a series of parametric studies regarding thermal-mechanical coupling models employed in finite element analysis in order to assess the behavior and dynamic response of representative materials and geometries under various boundary conditions. Fiber ferrule and ferrule housing dimensions affect resistance to bending and torsion, which in turn governs the magnitude of the displacement field. The models are then applied to geometries typical of alignment fixtures used in laser diode packages. The effects of laser energy deposition location and resolution as well as assumed boundary and initial conditions are also discussed. Convection and the small variations in ferule geometry do not have a strong effect on the overall response.

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