Asymptotic crack tip fields for pressure-sensitive materials and dynamic crack growth under plane stress conditions

1996 ◽  
Vol 74 (3) ◽  
pp. R53-R61 ◽  
Author(s):  
K. P. Herrmann ◽  
B. Potthast
Keyword(s):  
Crack Growth ◽  
Plane Stress ◽  
Crack Tip ◽  
Stress Conditions ◽  
Dynamic Crack ◽  
Dynamic Crack Growth ◽  
Crack Tip Fields ◽  
Pressure Sensitive

Characteristic Parameters of Dynamic Crack Growth along the Interface between the Two Orthotropic Materials

2012 ◽  
Vol 452-453 ◽  
pp. 1184-1189
Author(s):  
Jelena M. Djokovic ◽  
Ružica R. Nikolić
Keyword(s):  
Crack Growth ◽  
Interfacial Crack ◽  
Crack Tip ◽  
Micromechanical Modeling ◽  
Orthotropic Materials ◽  
Dynamic Crack ◽  
Crack Speed ◽  
Energy Factor ◽  
Dynamic Crack Growth ◽  
Resolution Factor

In this paper is analyzed the behavior of parameters that characterize the process of a dynamic crack growth along the interface between the two orthotropic materials. The emphasis is placed on the application of the fracture mechanics concept for the interfacial crack that propagates dynamically, at high speed. In this work is considered the behavior of the oscillation index, the traction resolution factor and the energy factor depending on the crack tip speed and the stifnesses ratio. The oscillatory index increases with the crack tip speed and tends to infinity when the crack speed approaches the Rayleigh wave speed of the less stiff of the two materials. The traction resolution factor depends strongly on the crack speed but weakly on the stiffness ratio. The behavior of the energy factor is completely different from the behavior of the traction resolution factor. Results provided in this paper can be used as a guide for micromechanical modeling of materials.

Mixed-Mode Dynamic Crack Growth in a Functionally Graded Particulate Composite: Experimental Measurements and Finite Element Simulations

2008 ◽  
Vol 75 (5) ◽  
Author(s):  
Madhu Kirugulige ◽  
Hareesh V. Tippur
Keyword(s):  
Finite Element ◽  
Crack Growth ◽  
Material Properties ◽  
Mixed Mode ◽  
Crack Tip ◽  
Functionally Graded ◽  
Dynamic Crack ◽  
Cohesive Elements ◽  
Dynamic Crack Growth ◽  
Crack Paths

Mixed-mode dynamic crack growth behavior in a compositionally graded particle filled polymer is studied experimentally and computationally. Beams with single edge cracks initially aligned in the direction of the compositional gradient and subjected to one-point eccentric impact loading are examined. Optical interferometry along with high-speed photography is used to measure surface deformations around the crack tip. Two configurations, one with a crack on the stiffer side of a graded sheet and the second with a crack on the compliant side, are tested. The observed crack paths are distinctly different for these two configurations. Furthermore, the crack speed and stress intensity factor variations between the two configurations show significant differences. The optical measurements are examined with the aid of crack-tip fields, which incorporate local elastic modulus variations. To understand the role of material gradation on the observed crack paths, finite element models with cohesive elements are developed. A user-defined element subroutine for cohesive elements based on a bilinear traction-separation law is developed and implemented in a structural analysis environment. The necessary spatial variation of material properties is introduced into the continuum elements by first performing a thermal analysis and then by prescribing material properties as temperature dependent quantities. The simulated crack paths and crack speeds are found to be in qualitative agreement with the observed ones. The simulations also reveal differences in the energy dissipation in the two functionally graded material (FGM) cases. T-stresses and hence the crack-tip constraint are significantly different. Prior to crack initiation, larger negative T-stresses near the crack tip are seen when the crack is situated on the compliant side of the FGM.

Overload effects on fatigue crack-tip fields under plane stress conditions: surface and bulk analysis

2012 ◽  
Vol 36 (1) ◽  
pp. 75-84 ◽  
Author(s):  
P. LOPEZ-CRESPO ◽  
P. J. WITHERS ◽  
F. YUSOF ◽  
H. DAI ◽  
A. STEUWER ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Plane Stress ◽  
Crack Tip ◽  
Stress Conditions ◽  
Bulk Analysis ◽  
Crack Tip Fields

scholarly journals Crack Growth Behavior in NiTi Shape Memory Alloys Under Mode-I Isothermal Loading: Effect of Stress State

2018 ◽  
Author(s):  
Behrouz Haghgouyan ◽  
Ibrahim Karaman ◽  
Sameer Jape ◽  
Alexandros Solomou ◽  
Dimitris C. Lagoudas
Keyword(s):  
Finite Element ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Crack Growth ◽  
Plane Strain ◽  
Plane Stress ◽  
Crack Tip ◽  
Stress Conditions ◽  
Mode I ◽  
Niti Shape Memory Alloys

Fracture behavior in nickel-titanium (NiTi) shape memory alloys (SMAs) subjected to mode-I, isothermal loading is studied using finite element analysis (FEA). Compact tension (CT) SMA specimen is modeled in Abaqus finite element suite and crack growth under displacement boundary condition is investigated for plane strain and plane stress conditions. Parameters for the SMA material constitutive law implemented in the finite element setup are acquired from characterization tests conducted on near-equiatomic NiTi SMA. Virtual crack closure technique (VCCT) is implemented where crack is assumed to extend when the energy release rate at the crack-tip becomes equal to the experimentally obtained material-specific critical value. Load-displacement curves and mechanical fields near the crack-tip in plane strain and plane stress cases are examined. Moreover, a discussion with respect to the crack resistance R-curves calculated using the load-displacement response for plane strain and plane stress conditions is presented.

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