scholarly journals Numerical evaluation of crack stopping mechanisms in composite bonded joints due to corrugation and bolts

2019 ◽  
Vol 304 ◽  
pp. 01003 ◽  
Author(s):  
Konstantinos Tserpes
Keyword(s):  
Crack Growth ◽  
Cohesive Zone ◽  
Cohesive Zone Modeling ◽  
Bonded Joints ◽  
Adhesively Bonded ◽  
Static Loads ◽  
Lap Shear ◽  
Crack Growth Simulation ◽  
Zone Modeling ◽  
Fatigue Loads

In this paper, the crack stopping mechanisms in corrugated composite bonded joints and hybrid bonded/bolted joints were evaluated numerically using the cohesive zone modeling approach. For the study, the DCB (double-cantilever beam) and the CLS (crack-lap shear) specimens were modelled. The first two specimens were subjected to static loads and the latter both to static and fatigue loads. The analysis was performed using the LS-DYNA explicit FE code. Fatigue crack growth simulation was performed using an in-house developed user-defined subroutine (UMAT). The numerical results reveal a crack stopping in the corrugated DCB, no crack stopping in the corrugated CLS and a reduction of crack growth rate in the bonded/bolted CLS for both static and fatigue loads. The methods and the findings of the present study can be used for the design of crack stopping features in adhesively bonded primary composite aircraft structures.

Singularities at Solder Joint Interfaces and Their Effects on Fracture Models

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
D. Bhate ◽  
D. Chan ◽  
G. Subbarayan ◽  
L. Nguyen ◽  
J. Zhao ◽  
...  
Keyword(s):  
Solder Joint ◽  
Crack Growth ◽  
Cohesive Zone ◽  
Cohesive Zone Modeling ◽  
Damage Modeling ◽  
Element Analysis ◽  
Strain Behavior ◽  
Modeling Approach ◽  
Joint Fracture ◽  
Zone Modeling

In this study, we focus on investigating the nature of the stress and strain behavior in solder joints and their effect on the hybrid damage modeling approach, which is inspired by cohesive zone modeling and Weibull functions [Towashiraporn, et al., 2005, “A Hybrid Model for Computationally Efficient Fatigue Fracture Simulations at Microelectronic Assembly Interfaces,” Int. J. Solids Struct., 42(15), pp. 4468–4483]. We review well understood principles in elastic-plastic fracture mechanics and more recent work in cohesive zone modeling, that address the nature of the singular solutions at the crack tip and provide insight when dealing with the more complex problem of solder joint fracture. Using three-dimensional finite element analysis of a chip scale package, we systematically examine the stress-strain behavior at the edge of the solder joint along the interface. The singular nature of the behavior manifests itself as mesh dependence of the predicted crack front shape and the cycles to failure. We discuss the conditions under which the predicted crack growth rate is of reasonable accuracy by incorporating a characteristic length measure. We validate predictions made by the hybrid damage modeling approach against a companion experimental study in which crack growth was tracked in packages subjected to accelerated thermal cycling.

scholarly journals Investigation of Defect Effects on Adhesively Bonded Joint Strength Using Cohesive Zone Modeling

2018 ◽  
Vol 68 (3) ◽  
pp. 5-24
Author(s):  
Jamal-Omidi Majid ◽  
Mohammadi Suki Mohammad Reza
Keyword(s):  
Material Properties ◽  
Cohesive Zone ◽  
Joint Strength ◽  
Adhesive Layer ◽  
Cohesive Zone Modeling ◽  
Adhesively Bonded ◽  
Bonded Joint ◽  
Degraded Material ◽  
Zone Modeling ◽  
Adhesively Bonded Joint

AbstractIn this paper, effects of the defect in an adhesively bonded joint have been investigated using cohesive zone modeling. Consequently, a 3D finite element model of a single lap-joint is constructed and validated with experiments. Strength prediction of current model is found desirable. Accordingly, different sizes of square shape defects are imported to model in the form of changing (raised or degraded) material properties (heterogeneity) and locally delaminated areas (as inclusion/void), respectively. Joint strength is investigated and a stress analysis is carried out for adhesive layer and adherends. Obtained Results show that, defect has significant impact on the results. It is found that at constant size of defect, local delamination has more impact on bonded joint strength than the heterogeneity. Furthermore, stress analyses demonstrate that the stress field does not change in adherends by taking defects into account. However, stress values decrease with degraded material properties and joint’s strength. Through evaluation of peel and transverse shear stresses in adhesive layer it is found that there is a change of stress distribution for both types of defects. Whereas, there is a considerable stress concentration in the delaminated adhesive layer.

Cohesive Zone Modeling of Mode I Fracture in Adhesive Bonded Joints

2007 ◽  
pp. 13-16 ◽  
Author(s):  
Marco Alfano ◽  
Franco Furgiuele ◽  
A. Leonardi ◽  
Carmine Maletta ◽  
Glaucio H. Paulino
Keyword(s):  
Cohesive Zone ◽  
Cohesive Zone Modeling ◽  
Mode I ◽  
Bonded Joints ◽  
Mode I Fracture ◽  
Zone Modeling ◽  
Adhesive Bonded Joints

Cohesive Zone Modeling of Ductile Crack Growth in Circumferential Through-Wall-Cracked Pipe Tests

2011 ◽  
Author(s):  
Do-Jun Shim ◽  
Mohammed Uddin ◽  
Frederick Brust ◽  
Gery Wilkowski
Keyword(s):  
Crack Growth ◽  
Cohesive Zone ◽  
Bending Moment ◽  
Growth Behavior ◽  
Cohesive Zone Modeling ◽  
Crack Growth Behavior ◽  
Ductile Crack ◽  
Element Analysis ◽  
Ductile Crack Growth ◽  
Zone Modeling

Cohesive zone modeling has been shown to be a convenient and effective method to simulate and analyze the ductile crack growth behavior in fracture specimens and structures. However, the cohesive zone modeling has not been applied to simulate the ductile crack growth behavior of a circumferential through-wall cracked pipe. In this paper, cohesive zone modeling has been applied to simulate the ductile crack growth of a past through-wall-cracked pipe test that was conducted during Degraded Piping Program. The ABAQUS code was used for the three-dimensional finite element analysis. The bending moment at crack initiation, maximum bending moment, crack extension, and J-integral values were calculated from the finite element analysis. These results were compared with the experimental results. In addition, results obtained from an existing J-estimation scheme (LBB.ENG2) were provided for comparison. All results showed reasonable agreement. The results of the present study demonstrate that the cohesive zone modeling can be applied to simulate the ductile crack growth behavior of a through-wall cracked pipe.

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