scholarly journals Fatigue Life Prediction of the Zirconia Fixture Based on Boundary Element Method

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Y. W. Wang ◽  
J. J. Ye ◽  
W. P. He ◽  
G. G. Cai ◽  
B. Q. Shi
Keyword(s):  
Fatigue Life ◽  
Boundary Element Method ◽  
Boundary Element ◽  
Crack Growth ◽  
Semiconductor Industry ◽  
Element Model ◽  
Stress Distributions ◽  
Paris Law ◽  
Initial Cracks ◽  
Element Method

Zirconia grinding fixtures have been widely used in semiconductor industry to improve the quality and precision of the products. For maximizing the service life and minimizing the risks of accidental damage, it is critical to have a better understanding of the fatigue life of zirconia grinding fixtures. To this end, a boundary element method is developed in this paper to investigate their crack growth and fatigue life. To validate the proposed method, the stress intensity factor of a typical plate structure with initial cracks is considered. On this basis, Paris Law is employed in the boundary element model to further study the crack growth and stress distributions in the zirconia fixture under cyclic loads. Numerical results show that stress concentration occurs at the pillar of the fixture, and crack growth is perpendicular to the loading direction.

scholarly journals A Probabilistic Approach in Fuselage Damage Analysis via Boundary Element Method

2021 ◽  
Author(s):  
Gilberto Gomes ◽  
Thiago Oliveira ◽  
Francisco Evangelista Jr
Keyword(s):  
Fatigue Life ◽  
Boundary Element Method ◽  
Boundary Element ◽  
Damage Tolerance ◽  
Classical Model ◽  
Limit State ◽  
Probabilistic Approach ◽  
Computational Techniques ◽  
Aircraft Fuselage ◽  
Element Method

This chapter presents a new alternative approach to the analysis of the fatigue life of aircraft fuselage parts considering the compliance of internal elements to replace the classical model of critical crack size. In this case, from a global–local analysis using the boundary element method (BEM), induced stresses at a macro model, and their effects on micro models are evaluated. The BEM enables efficient simulations of the propagation of initial defects to assess the damage tolerance. For this purpose, computational techniques were developed that allowed evaluating these models, through a probabilistic treatment to assess damage tolerance and fatigue life. Finally, this technique is shown as an alternative to ensure the integrity and proper operation of fuselage panels avoiding reaching a Limit State during its projected lifespan.

scholarly journals Fracture Characteristics Analysis of Pressured Pipeline with Crack Using Boundary Element Method

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Han-Sung Huang
Keyword(s):  
Boundary Element Method ◽  
Service Life ◽  
Boundary Element ◽  
Crack Growth ◽  
Longitudinal Crack ◽  
Fatigue Loading ◽  
Longitudinal Direction ◽  
Uniform Corrosion ◽  
Loading Cycle ◽  
Element Method

Metal materials can inevitably show deteriorated properties by the factors of stress, temperature, and environmental erosion in distinct operating environments. Without proper protection, the service life would be shortened or even deadly danger would be caused. This study aims to apply Finite Element Method and Boundary Element Method to analyzing the effects of corroded petrochemical pipes on the fatigue life and the fracture form. The research results of nondestructive testing and software analyses show that cracked oil pipes with uniform corrosion bear larger stress, mainly internal pressure, on the longitudinal direction than the circumferential direction. As a result, the maximal fatigue loading cycle of a circumferential crack is higher than that of a longitudinal one. From the growing length and depth of a crack, the final aspect ratio of crack growth appears in 2.42–3.37 and 2.71–3.42 on the circumferential and longitudinal direction, respectively. Meanwhile, the ratios of loading cycles of circumferential and longitudinal crack are 26.23 on uncorroded and 20.54 on general metal loss oil pipe. The complete crack growth and the correspondent fatigue loading cycle could be acquired to determine the service life of the oil pipe being operated as well as the successive recovery time.

Unsteady thermal stress analysis in three-dimensional problems by means of the thermoelastic displacement potential and the boundary element method

1990 ◽  
Vol 25 (1) ◽  
pp. 9-14 ◽  
Author(s):  
Y Ochiai ◽  
R Ishida ◽  
T Sekiya
Keyword(s):  
Thermal Stress ◽  
Boundary Element Method ◽  
Boundary Element ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
Stress Distributions ◽  
Displacement Potential ◽  
Thermal Displacements ◽  
Thermoelastic Displacement ◽  
Element Method

A numerical method to analyse unsteady thermal stresses in three-dimensional problems is proposed. It is shown that three-dimensional unsteady thermal stress problems can be easily solved without the volume integral by means of the thermoelastic displacement potential and the boundary element method. It is also shown that the time integral can be easily carried out analytically. In order to investigate the accuracy of this method, unsteady thermal stress distributions for a sphere and a circular cylinder are obtained. As a numerical example for which it is difficult to obtain the analytical solution, thermal displacements and surface stress distributions for a torus are obtained.

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