“Trident” Model of Plastic Zone at the End of a Mode I Crack Appearing on the Nonsmooth Interface of Materials

2015 ◽  
Vol 50 (4) ◽  
pp. 516-526 ◽  
Author(s):  
M. V. Dudyk ◽  
Yu. V. Dikhtyarenko
Keyword(s):  
Plastic Zone ◽  
Mode I ◽  
Mode I Crack

A Plastic Zone Equation Based on Mean Yield Criterion

2010 ◽  
Vol 97-101 ◽  
pp. 534-537 ◽  
Author(s):  
Wei Deng ◽  
De Wen Zhao ◽  
Xiao Mei Qin ◽  
Xiu Hua Gao ◽  
Chun Lin Qiu ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Analytical Solution ◽  
Plastic Zone ◽  
Yield Criterion ◽  
Small Scale ◽  
Mode I ◽  
Mode I Crack ◽  
Small Scale Yielding ◽  
Scale Yielding ◽  
My Criterion

Based on mean yield criterion, an analytical solution for the mode I crack tip plastic zone (CTPZ) under small scale yielding was derived. The results reveal that the size of CTPZ determined by MY criterion is between those by Mises’ yield criterion the smallest, and by Tresca’s criterion the largest; while the zone is almost coincide with that by Mises’ one. The size of CTPZ is related to the ratio of fracture toughness to yield strength; with increasing of the ratio, the size of the zone increases, meaning the better of fracture toughness.

Cracks

2020 ◽  
pp. 179-220
Author(s):  
Adrian P. Sutton
Keyword(s):  
Plastic Zone ◽  
Crack Tip ◽  
Singular Integral Equations ◽  
Energy Criterion ◽  
Mode I ◽  
Cauchy Type ◽  
Mode I Crack ◽  
Burgers Vector ◽  
Elastic Fields ◽  
Free Zone

Loaded slit cracks are modelled as continuous distributions of dislocations with infinitesimal Burgers vectors. Cauchy-type singular integral equations for the density of Burgers vector in these distributions are solved using the theory of Chebyshev polynomials. The elastic fields of mode I elastic slit cracks are derived and the stress intensity factor is defined. Other defects may interact with cracks such as dislocations. This leads to the concepts of shielding and anti-shielding of cracks by dislocations. The Dugdale–Bilby–Cottrell–Swinden model of a mode I crack completely shielded by a plastic zone is derived. By introducing a dislocation free zone between the plastic zone and the crack tip the crack tip is only partially shielded, enabling more brittle tendencies to be described. Griffith’s energy criterion for the growth of an existing crack is seen as necessary but not sufficient. The Barenblatt crack introduces the influence of interatomic forces at the crack tip.

A mode I crack with multiple islands of ideal contact between the crack faces: An asymptotic model

2021 ◽  
pp. 108128652110214
Author(s):  
Ivan Argatov
Keyword(s):  
Crack Opening ◽  
Reduction Factor ◽  
Mode I ◽  
Asymptotic Model ◽  
Mode I Crack ◽  
Opening Displacement ◽  
Multiple Contacts ◽  
Scaling Hypothesis ◽  
Penny Shaped Crack ◽  
Crack Faces

The problem of a mode I crack having multiple contacts between the crack faces is considered. In the case of small contact islands of arbitrary shapes, which are arbitrarily located inside the crack, the first-order asymptotic model for the crack opening displacement is constructed using the method of matched asymptotic expansions. The case of a penny-shaped crack has been studied in detail. A scaling hypothesis for the compliance reduction factor is formulated.

scholarly journals Mode I Crack Propagation Experimental Analysis of Adhesive Bonded Joints Comprising Glass Fibre Composite Material under Impact and Constant Amplitude Fatigue Loading

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4380
Author(s):  
Alirio Andres Bautista Villamil ◽  
Juan Pablo Casas Rodriguez ◽  
Alicia Porras Holguin ◽  
Maribel Silva Barrera
Keyword(s):  
Crack Propagation ◽  
Structural Integrity ◽  
Crack Propagation Rate ◽  
Fatigue Loading ◽  
Propagation Rate ◽  
Operating Conditions ◽  
Impact Testing ◽  
Mode I ◽  
Mode I Crack ◽  
Constant Amplitude

The T-90 Calima is a low-wing monoplane aircraft. Its structure is mainly composed of different components of composite materials, which are mainly bonded by using adhesive joints of different thicknesses. The T-90 Calima is a trainer aircraft; thus, adverse operating conditions such as hard landings, which cause impact loads, may affect the structural integrity of aircrafts. As a result, in this study, the mode I crack propagation rate of a typical adhesive joint of the aircraft is estimated under impact and constant amplitude fatigue loading. To this end, effects of adhesive thickness on the mechanical performance of the joint under quasistatic loading conditions, impact and constant amplitude fatigue in double cantilever beam (DCB) specimens are experimentally investigated. Cyclic impact is induced using a drop-weight impact testing machine to obtain the crack propagation rate (da/dN) as a function of the maximum strain energy release rate (GImax) diagram; likewise, this diagram is also obtained under constant amplitude fatigue, and both diagrams are compared to determine the effect of each type of loading on the structural integrity of the joint. Results reveal that the crack propagation rate under impact fatigue is three orders of magnitude greater than that under constant amplitude fatigue.

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