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.

Performance of Cohesive Zone Models for Brittle and Ductile Adhesives

2014 ◽  
Vol 941-944 ◽  
pp. 2089-2092
Author(s):  
Jun Zhang ◽  
Hong Jia
Keyword(s):  
Cohesive Zone ◽  
Shear Failure ◽  
Pure Shear ◽  
Adhesive Layer ◽  
Adhesively Bonded ◽  
Cohesive Zone Models ◽  
Pure Tension ◽  
Bonded Joint ◽  
Adhesively Bonded Joint ◽  
Delamination Behavior

Damage modeling approach is increasingly used to simulate fracture and debonding processes in adhesively bonded joint. In order to understand the relation between the delamination behavior of different types of adhesives and the type of cohesive zone models (CZMs), the pure tension and pure shear experiments were conducted used two distinct adhesives, an epoxy-based adhesive in a brittle manner and VHBTM tape adhesive in a ductile manner. The traction-separation relations of the two adhesives were extracted from the tension and shear experimental results. Three types of cohesive zone models (CZMs) are adopted, including the exponential, bilinear, and trapezoidal models. VUMAT subroutine of CZMs as the adhesive layer is used to simulate the specimen tension and shear debonding procedures. The results demonstrate that (i) the bilinear CZM more suitably describes the brittle adhesive and the exponential CZM suitably describes the ductile adhesive to simulate the tension and shear failure. (ii) cohesive strength and work of separation are the significant affections on the simulation results. and (iii) the shape of CZM is a significant affections on the simulation the pure tension and shear debonding procedure.

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.

153 Improvement of Joint Strength for Adhesively Bonded Joint by Easy Machining Adherend

2015 ◽  
Vol 2015 (0) ◽  
pp. 28-29
Author(s):  
Tetsushi SANO ◽  
Jyo SHIMURA ◽  
Shigeru KUROSAKI ◽  
Mutsumi MIYAGAWA
Keyword(s):  
Joint Strength ◽  
Adhesively Bonded ◽  
Bonded Joint ◽  
Adhesively Bonded Joint

Fracture Characteristics of Shear Adhesive Dissimilar Joint

2014 ◽  
Vol 606 ◽  
pp. 165-169
Author(s):  
Mohd Afendi ◽  
Ku Hafizan ◽  
M.S. Abdul Majid ◽  
R. Daud ◽  
N.A.M. Amin ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Shear Strength ◽  
Interface Crack ◽  
Adhesive Joint ◽  
Adhesive Layer ◽  
Stress Distributions ◽  
Adhesively Bonded ◽  
Shear Joint ◽  
Bonded Joint ◽  
Adhesively Bonded Joint

In this study, the effect of bond thickness upon shear strength and fracture toughness of epoxy adhesively bonded joint with dissimilar adherents was addressed. The bond thickness, t between the adherents was controlled to be ranged between 0.1 mm and 1.2 mm. Finite element analyses were also executed by commercial ANSYS 11 code to investigate the stress distributions within the adhesive layer of adhesive joint. As a result, shear strength of adhesive joint reduces with increasing bond thickness. The strength of shear adhesive joint was also depended on elastic modulus of adherent. Moreover, the failure of dissimilar adherents bonded shear joint originated at a location with critical stress-y which was the interface corner of ALYH75/epoxy. In the case of shear adhesive joint with an interface crack, the fracture also occurred at the ALYH75/epoxy interface even in the steel-adhesive-aluminum (SEA) specimens. Fracture toughness, Jc of aluminum-adhesive-steel (AES) joints was similar to those of SES and demonstrates strong dependency upon bond thickness. Furthermore, the interface crack in SEA specimen has relatively large fracture resistance if compared to those in AES specimen. Finally, Kc fracture criterion was found to be appropriate for shear adhesive joints associated with adhesive fracture.

Normal Stress Distributions in a Single-Lap Adhesively Bonded Joint under Tension

2012 ◽  
Vol 530 ◽  
pp. 9-13 ◽  
Author(s):  
Xiao Cong He
Keyword(s):  
Finite Element ◽  
Normal Stress ◽  
High Stress ◽  
Three Dimensional ◽  
Adhesive Layer ◽  
Adhesively Bonded ◽  
Element Analysis ◽  
Normal Stress Distribution ◽  
Bonded Joint ◽  
Adhesively Bonded Joint

This paper investigates normal stress distribution of a single-lap adhesively bonded joint under tension using the three-dimensional finite element methods. Five layers of solid elements were used across the adhesive layer thickness in order to obtain an accurate indication of the variation of normal stress. All the numerical results obtained from the finite element analysis show that the spatial distribution of normal stress are similar for different interfaces though the stress values are obviously different. It can also be seen from the results that the left hand region, which is very close to the left free end of the adhesive layer, is subjected to very high stress and the magnitude of the normal stress oscillates in value close to the left end of the adhesive layer.

Evaluation of adhesively bonded joint strength of CFRP with laser treatment

2015 ◽  
Vol 25 (4) ◽  
pp. 317-327 ◽  
Author(s):  
Tomohiro Yokozeki ◽  
Masaru Ishibashi ◽  
Yayoi Kobayashi ◽  
Hideyasu Shamoto ◽  
Yutaka Iwahori
Keyword(s):  
Laser Treatment ◽  
Joint Strength ◽  
Adhesively Bonded ◽  
Bonded Joint ◽  
Adhesively Bonded Joint
Sign in / Sign up

Export Citation Format

Share Document