Finite element method for cutoff frequencies of weakly guiding fibres of arbitrary cross-section

1984 ◽  
Vol 16 (6) ◽  
pp. 487-493 ◽  
Author(s):  
K. S. Chiang
2019 ◽  
Vol 8 (4) ◽  
pp. 2656-2661

The design of the Gravity retaining wall (GRW) is a trial and error process. Prevailing conditions of backfill are used to determine the profile of GRW, which proceeds with the selection of provisional dimensions. The optimum section is having factors of safety of stability higher than the allowable values and stresses in the cross-section smaller than permissible. The cross-section is designed to fulfill conditions of stability, subjected to very low stresses. The strength of the material, which is provided in the cross-section remains unutilized. A computer program is developed to find stresses at various locations on the cross-section of GRW using the Finite Element Method (FEM). A discontinuity in the form of a rectangular cavity is introduced in the cross-section of GRW to optimize it. The rectangular cavity is introduced in the cross-section of GRW at different locations. An attempt is made in this paper to find the stress distribution in the gravity retaining wall cross-section and to study the effect of the rectangular cavity on the stress distribution. Two cases representing different locations are considered to study the effect of the cavity. The location of the cavity is distinguished by the parameter w, the effects of cases with varied was 0.2305 (Case-I) and 0.1385 (Case-II) are observed. The cavity, which is provided not only makes the wall structurally efficient but also economically feasible.


2009 ◽  
Vol 25 (4) ◽  
pp. 401-409 ◽  
Author(s):  
A. Doostfatemeh ◽  
M. R. Hematiyan ◽  
S. Arghavan

ABSTRACTSome analytical formulas are presented for torsional analysis of homogeneous hollow tubes. The cross section is supposed to consist of straight and circular segments. Thicknesses of segments of the cross section can be different. The problem is formulated in terms of Prandtl's stress function. The derived approximate formulas are so simple that computations can be carried out by a simple calculator. Several examples are presented to validate the formulation. The accuracy of formulas is verified by accurate finite element method solutions. It is seen that the error of the formulation is small and the formulas can be used for analysis of thin to moderately thick-walled hollow tubes.


2012 ◽  
Vol 09 (01) ◽  
pp. 1240006 ◽  
Author(s):  
SHANGMING LI

A unified scaled boundary finite element method (SBFEM) in the frequency domain was proposed for a semi-infinite reservoir with uniform cross section subjected to horizontal and vertical ground excitations, and a methodology was presented to solve the unified SBFEM through decomposing the unified SBFEM into two parts; one part modeling the reservoir subjected to horizontal excitations and the other part modeling the whole reservoir subjected to vertical excitations. The accuracy of the unified SBFEM and its solving methodology was validated through analyzing numerical examples. The SBFEM solutions were in good agreement with analytical or other numerical method's solutions.


2018 ◽  
Vol 10 (04) ◽  
pp. 1850039 ◽  
Author(s):  
Mohsen Mirzajani ◽  
Naser Khaji ◽  
Muneo Hori

The wave finite element method (WFEM) is developed to simulate the wave propagation in one-dimensional problem of nonhomogeneous linear micropolar rod of variable cross-section. For this purpose, two kinds of waves with fast and slow velocities are detected. For micropolar medium, an additional rotational degree of freedom (DOF) is considered besides the classical elasticity’s DOF. The proposed method is implemented to solve the wave propagation, reflection and transmission of two distinct waves and impact problems in micropolar rods with different layers. Along with new solutions, results of the micropolar wave finite element method (MWFEM) are compared with some numerical and/or analytical solutions available in the literature, which indicate excellent agreements between the results.


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