Influences of angular deceleration on the thermoelastoplastic behaviors of nonuniform thickness multilayer FGM discs

2020 ◽  
pp. 113092
Author(s):  
A.M. Eldeeb ◽  
Y.M. Shabana ◽  
A. Elsawaf
Keyword(s):  
Nonuniform Thickness

Displacement and Stress Fields in a Functionally Graded Fiber-Reinforced Rotating Disk With Nonuniform Thickness and Variable Angular Velocity

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Y. Zheng ◽  
H. Bahaloo ◽  
D. Mousanezhad ◽  
A. Vaziri ◽  
H. Nayeb-Hashemi
Keyword(s):  
Radial Direction ◽  
Volume Fraction ◽  
Rotating Disk ◽  
Outer Radius ◽  
Functionally Graded ◽  
Circumferential Direction ◽  
Stress Fields ◽  
Fiber Reinforced ◽  
Inner Radius ◽  
Nonuniform Thickness

Displacement and stress fields in a functionally graded (FG) fiber-reinforced rotating disk of nonuniform thickness subjected to angular deceleration are obtained. The disk has a central hole, which is assumed to be mounted on a rotating shaft. Unidirectional fibers are considered to be circumferentially distributed within the disk with a variable volume fraction along the radius. The governing equations for displacement and stress fields are derived and solved using finite difference method. The results show that for disks with fiber rich at the outer radius, the displacement field is lower in radial direction but higher in circumferential direction compared to the disk with the fiber rich at the inner radius. The circumferential stress value at the outer radius is substantially higher for disk with fiber rich at the outer radius compared to the disk with the fiber rich at the inner radius. It is also observed a considerable amount of compressive stress developed in the radial direction in a region close to the outer radius. These compressive stresses may prevent any crack growth in the circumferential direction of such disks. For disks with fiber rich at the inner radius, the presence of fibers results in minimal changes in the displacement and stress fields when compared to a homogenous disk made from the matrix material. In addition, we concluded that disk deceleration has no effect on the radial and hoop stresses. However, deceleration will affect the shear stress. Tsai–Wu failure criterion is evaluated for decelerating disks. For disks with fiber rich at the inner radius, the failure is initiated between inner and outer radii. However, for disks with fiber rich at the outer radius, the failure location depends on the fiber distribution.

Geometrical Stress-Reducing Factors in the Anisotropic Porcine Heart Valves

2003 ◽  
Vol 125 (5) ◽  
pp. 735-744 ◽  
Author(s):  
X. Y. Luo ◽  
W. G. Li ◽  
J. Li
Keyword(s):  
Heart Valves ◽  
Transversely Isotropic ◽  
Element Model ◽  
Parameter Study ◽  
Geometrical Parameters ◽  
Aortic Valves ◽  
Stress Variation ◽  
Nonuniform Thickness ◽  
Geometrical Factors ◽  
Parameter Ranges

This study carries out a detailed parameter study based on a nonlinear anisotropic finite-element model published previously. The aim of this study is to identify the stress-reducing influences from geometrical parameters such as stent height, valve diameter, and the nonuniform thickness of porcine aortic valves under static loading condition. The anisotropy of the valve is considered to be transversely isotropic with fibers oriented along the circumferential directions, which enables us to use a simple anisotropic constitutive model using uniaxial experimental data. The results showed that in general, higher stent height and smaller diameter combined with nonuniform thickness give rise to a much more reduced overall stress level. Although the absolute values of the peak stresses may be influenced by the detailed orientations of fibers, the trends of the stress variation with the geometrical factors seem to be qualitatively consistent within the parameter ranges considered.

Influence of nonuniform thickness of hemispherical resonator gyro shell on its unbalance parameters

2017 ◽  
Vol 8 (2) ◽  
pp. 97-103 ◽  
Author(s):  
M. A. Basarab ◽  
V. A. Matveev ◽  
B. S. Lunin ◽  
S. V. Fetisov
Keyword(s):  
Nonuniform Thickness ◽  
Hemispherical Resonator

Numerical Analysis of Superplastic Bulging Process of TiAl Sheet

2013 ◽  
Vol 747-748 ◽  
pp. 50-56
Author(s):  
Chuan Yun Wang ◽  
Jin Shan Li ◽  
Bin Tang ◽  
Hong Chao Kou
Keyword(s):  
Present Model ◽  
Thickness Distribution ◽  
Equivalent Plastic Strain ◽  
Element Model ◽  
Dominant Factor ◽  
Tial Alloys ◽  
Deformation Parameters ◽  
Nonuniform Thickness ◽  
Simulation Results ◽  
Good Agreement

The superplastic bulging process of TiAl sheet was simulated by coupling superplastic constitutive equation to finite element model. Based on this model, the effect of coefficient of friction between the sheet and mold and the size of the mold fillet on the superplastic bulging (SPB) performance of TiAl alloys sheet were studied by analyzing the evolution of equivalent plastic strain and thickness distribution in the sheet. The results showed that friction was the dominant factor of the nonuniform thickness of the sheet, while higher friction and smaller radius of mold fillet inhibited the over-thinning of sheet on the entry of mold cavity. The simulation results were in good agreement with the experimental results. Therefore, the present model could be used for optimizing the selction of the deformation parameters and the design of the structures.

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