A Non-Local Mode-I Cohesive Model for Ascending Thoracic Aorta Dissections (ATAD)

2018 ◽  
Author(s):  
Gioacchino Alotta ◽  
Emanuela Bologna ◽  
Marzio Di Giuseppe ◽  
Massimiliano Zingales ◽  
Rossana Dimitri ◽  
...  
Keyword(s):  
Thoracic Aorta ◽  
Local Mode ◽  
Mode I ◽  
Cohesive Model ◽  
Non Local

scholarly journals Thermal Delamination Modelling and Evaluation of Aluminium–Glass Fibre-Reinforced Polymer Hybrid

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 492
Author(s):  
Zhen Pei Chow ◽  
Zaini Ahmad ◽  
King Jye Wong ◽  
Seyed Saeid Rahimian Koloor ◽  
Michal Petrů
Keyword(s):  
Crack Front ◽  
Cohesive Zone ◽  
Experimental Tests ◽  
Mode I ◽  
Mode Ii ◽  
Cohesive Model ◽  
Reinforced Polymer ◽  
Glass Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Glass Fibre Reinforced

This paper aims to propose a temperature-dependent cohesive model to predict the delamination of dissimilar metal–composite material hybrid under Mode-I and Mode-II delamination. Commercial nonlinear finite element (FE) code LS-DYNA was used to simulate the material and cohesive model of hybrid aluminium–glass fibre-reinforced polymer (GFRP) laminate. For an accurate representation of the Mode-I and Mode-II delamination between aluminium and GFRP laminates, cohesive zone modelling with bilinear traction separation law was implemented. Cohesive zone properties at different temperatures were obtained by applying trends of experimental results from double cantilever beam and end notched flexural tests. Results from experimental tests were compared with simulation results at 30, 70 and 110 °C to verify the validity of the model. Mode-I and Mode-II FE models compared to experimental tests show a good correlation of 5.73% and 7.26% discrepancy, respectively. Crack front stress distribution at 30 °C is characterised by a smooth gradual decrease in Mode-I stress from the centre to the edge of the specimen. At 70 °C, the entire crack front reaches the maximum Mode-I stress with the exception of much lower stress build-up at the specimen’s edge. On the other hand, the Mode-II stress increases progressively from the centre to the edge at 30 °C. At 70 °C, uniform low stress is built up along the crack front with the exception of significantly higher stress concentrated only at the free edge. At 110 °C, the stress distribution for both modes transforms back to the similar profile, as observed in the 30 °C case.

Basic solution of two collinear mode-I cracks in the orthotropic medium by use of the non-local theory

2017 ◽  
Vol 13 (1) ◽  
pp. 100-115 ◽  
Author(s):  
Haitao Liu
Keyword(s):  
Stress Singularity ◽  
Local Theory ◽  
Mode I ◽  
Basic Solution ◽  
Orthotropic Medium ◽  
Dual Integral Equations ◽  
Content Type ◽  
Present Solution ◽  
Crack Tips ◽  
Non Local

Purpose The purpose of this paper is to present the basic solution of two collinear mode-I cracks in the orthotropic medium by the use of the non-local theory. Design/methodology/approach Meanwhile, the generalized Almansi’s theorem and the Schmidt method are used. By the Fourier transform, it is converted to a pair of dual integral equations. Findings Numerical examples are provided to show the effects of the crack length, the distance between the two collinear cracks and the lattice parameter on the stress field near the crack tips in the orthotropic medium. Originality/value The present solution exhibits no stress singularity at the crack tips in the orthotropic medium.

scholarly journals Effects of adhesive thickness on global and local Mode-I interfacial fracture of bonded joints

2010 ◽  
Vol 47 (18-19) ◽  
pp. 2445-2458 ◽  
Author(s):  
Gefu Ji ◽  
Zhenyu Ouyang ◽  
Guoqiang Li ◽  
Samuel Ibekwe ◽  
Su-Seng Pang
Keyword(s):  
Interfacial Fracture ◽  
Local Mode ◽  
Mode I ◽  
Bonded Joints ◽  
Adhesive Thickness ◽  
Global And Local

scholarly journals Mode mixity analysis of face/core debonds in a single cantilever beam sandwich specimen

2018 ◽  
Vol 22 (6) ◽  
pp. 1879-1909 ◽  
Author(s):  
Vishnu Saseendran ◽  
Christian Berggreen ◽  
Ronald Krueger
Keyword(s):  
Cantilever Beam ◽  
Critical Parameters ◽  
Local Mode ◽  
Mode I ◽  
Beam Specimen ◽  
Fracture Test ◽  
Mode Mixity ◽  
Shear Component ◽  
The Face ◽  
Sandwich Specimen

The single cantilever beam sandwich specimen has been proposed, as a fracture test standard for mode I peel loading. Critical parameters, including specimen dimensions, determine whether the crack propagates along the face/core interface in mode I during the fracture test. This paper outlines a parametric study based on a numerical method to examine local mode mixity conditions for a wide array of sandwich systems by varying several geometrical and material parameters. The thickness and modulus of the face sheet were seen to influence the mode mixity for most sandwich systems. Core Poisson’s ratio was shown to influence the local mode mixity and has the capability of driving the crack along the interface or into the core. The effect of the intact specimen length was analyzed and presented from a mode mixity perspective based on various elastic foundation modulus expressions. Reinforcement of the single cantilever beam specimen with stiff layers was also investigated numerically and compared with a similar analysis in the literature. The analysis presented in this paper shows that, despite reducing the global shear component, the local mode mixity condition deviated away from the mode I regime for several sandwich specimens. An appropriate foundation model along with a minimum loading rod length was one of the recommendations provided from the analyses, which may supplement the ASTM International standardization efforts.

Dynamic analysis of two collinear permeable Mode-I cracks in piezoelectric materials based on non-local piezoelectricity theory

2019 ◽  
Vol 15 (6) ◽  
pp. 1274-1293
Author(s):  
Haitao Liu ◽  
Shuai Zhu
Keyword(s):  
Piezoelectric Materials ◽  
Electric Displacement ◽  
Local Stress ◽  
Classical Solutions ◽  
Mode I ◽  
Dual Integral Equations ◽  
Content Type ◽  
Present Solution ◽  
Crack Tips ◽  
Non Local

Purpose Based on the non-local piezoelectricity theory, this paper is concerned with two collinear permeable Mode-I cracks in piezoelectric materials subjected to the harmonic stress wave. The paper aims to discuss this issue. Design/methodology/approach According to the Fourier transformation, the problem is formulated into two pairs of dual integral equations, in which the unknown variables are the displacement jumps across the crack surfaces. Findings Finally, the dynamic non-local stress and the dynamic non-local electric displacement fields near the crack tips are obtained. Numerical results are provided to illustrate the effects of the distance between the two collinear cracks, the lattice parameter and the circular frequency of the incident waves on the entire dynamic fields near the crack tips, which play an important role in designing new structures in engineering. Originality/value Different from the classical solutions, the present solution exhibits no stress and electric displacement singularities at the crack tips in piezoelectric materials. It is found that the maximum stress and maximum electric displacement can be used as a fracture criterion.

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