Determining indentation fracture toughness of ceramics by finite element method using virtual crack closure technique

2018 ◽  
Vol 197 ◽  
pp. 151-159 ◽  
Author(s):  
Liang Sun ◽  
Dejun Ma ◽  
Lizhi Wang ◽  
Xinzheng Shi ◽  
Jialiang Wang ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Fracture Toughness ◽  
Finite Element ◽  
Crack Closure ◽  
Virtual Crack Closure Technique ◽  
Indentation Fracture ◽  
Closure Technique ◽  
Indentation Fracture Toughness ◽  
Element Method

scholarly journals Cell-Based Smoothed Finite Element Method-Virtual Crack Closure Technique for a Piezoelectric Material of Crack

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Li Ming Zhou ◽  
Guang Wei Meng ◽  
Feng Li ◽  
Hui Wang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Crack Closure ◽  
Piezoelectric Materials ◽  
Piezoelectric Element ◽  
Fracture Analysis ◽  
Virtual Crack Closure Technique ◽  
Closure Technique ◽  
Smoothed Finite Element Method ◽  
Element Method

In order to improve the accuracy and efficiency of solving fracture parameters of piezoelectric materials, a piezoelectric element, tailored for the virtual crack closure technique (VCCT), was used to study piezoelectric materials containing a crack. Recently, the cell-based smoothed finite element method (CSFEM) and VCCT have been used to simulate the fracture mechanics of piezoelectric materials. A center cracked piezoelectric materials with different material properties, crack length, mesh, and smoothing subcells at various strain energy release rates are discussed and compared with finite element method-virtual crack closure technique (FEM-VCCT). Numerical examples show that CSFEM-VCCT gives an improved simulation compared to FEM-VCCT, which generally simulates materials as too stiff with lower accuracy and efficiency. Due to its simplicity, the VCCT piezoelectric element demonstrated in this study could be a potential tool for engineers to practice piezoelectric fracture analysis. CSFEM-VCCT is an efficient numerical method for fracture analysis of piezoelectric materials.

scholarly journals Analysis of Dynamic Fracture Parameters in Functionally Graded Material Plates with Cracks by Graded Finite Element Method and Virtual Crack Closure Technique

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Li Ming Zhou ◽  
Guang Wei Meng ◽  
Xiao Lin Li ◽  
Feng Li
Keyword(s):  
Finite Element ◽  
Crack Closure ◽  
Dynamic Fracture ◽  
Functionally Graded Material ◽  
Functionally Graded ◽  
Interface Element ◽  
Virtual Crack Closure Technique ◽  
Closure Technique ◽  
Graded Material ◽  
Element Method

Based on the finite element software ABAQUS and graded element method, we developed a dummy node fracture element, wrote the user subroutines UMAT and UEL, and solved the energy release rate component of functionally graded material (FGM) plates with cracks. An interface element tailored for the virtual crack closure technique (VCCT) was applied. Fixed cracks and moving cracks under dynamic loads were simulated. The results were compared to other VCCT-based analyses. With the implementation of a crack speed function within the element, it can be easily expanded to the cases of varying crack velocities, without convergence difficulty for all cases. Neither singular element nor collapsed element was required. Therefore, due to its simplicity, the VCCT interface element is a potential tool for engineers to conduct dynamic fracture analysis in conjunction with commercial finite element analysis codes.

scholarly journals Prediction of Characteristic Length and Fracture Toughness in Ductile-Brittle Transition

2008 ◽  
Author(s):  
Z. X. Wang ◽  
H. M. Li ◽  
Y. J. Chao ◽  
P. S. Lam
Keyword(s):  
Finite Element Method ◽  
Fracture Toughness ◽  
Finite Element ◽  
Characteristic Length ◽  
Crack Tip ◽  
Critical Distance ◽  
Transition Regime ◽  
Temperature Dependent ◽  
Brittle Transition ◽  
Element Method

Finite element method was used to analyze the three-point bend experimental data of A533B-1 pressure vessel steel obtained by Sherry, Lidbury, and Beardsmore [1] from −160 to −45 °C within the ductile-brittle transition regime. As many researchers have shown, the failure stress (σf) of the material could be approximated as a constant. The characteristic length, or the critical distance (rc) from the crack tip, at which σf is reached, is shown to be temperature dependent based on the crack tip stress field calculated by the finite element method. With the J-A2 two-parameter constraint theory in fracture mechanics, the fracture toughness (JC or KJC) can be expressed as a function of the constraint level (A2) and the critical distance rc. This relationship is used to predict the fracture toughness of A533B-1 in the ductile-brittle transition regime with a constant σf and a set of temperature-dependent rc. It can be shown that the prediction agrees well with the test data for wide range of constraint levels from shallow cracks (a/W = 0.075) to deep cracks (a/W = 0.5), where a is the crack length and W is the specimen width.

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