Mechanical Performance Analysis of Composite Scarf Joints with Debond Flaw

2014 ◽  
Vol 1016 ◽  
pp. 95-99 ◽  
Author(s):  
Xia Guo ◽  
Zeng Shan Li ◽  
Wen Chao Zhang ◽  
Ri Ming Tan ◽  
Zhi Dong Guan

The adhesive structural mechanical performance is influenced by debond flaw. This paper presents a research on the effect of flaws on the mechanical performance of composite scarf joints. The experimental results show that the load-carrying capacity of composite scarf joints changed along with the location of the debond flaw. The location of the flaw in the bondline influences the failure mode. Additionally, the finite element method was employed to obtain the failure mode of the composite scarf joint. The adhesively bonded joints were modeled using ABAQUS software. The computational results show that flaws located at the edge of the bond region result in more pronounced load reduction than which located at the middle of bond region.

2005 ◽  
Vol 13 (4) ◽  
pp. 359-370 ◽  
Author(s):  
Makoto Imanaka ◽  
Makoto Taniguchi ◽  
Tatuyuki Hamano ◽  
Masaki Kimoto

An estimation method of fatigue strength of adhesively bonded joints with various stress triaxialities in the adhesive layer has been proposed based on a damage evolution model for high cycle fatigue. To realize various triaxial stress states, fatigue test was conducted for adhesively bonded butt and scarf joints with various scarf angles bonded by a rubber-modified epoxy adhesive. An equation for estimating the damage evolution in the adhesive layer of the butt and scarf joints was derived from the damage model, where undefined parameters in the equation were determined by comparing the experimentally obtained damage evolution curves of the butt joints with the estimated damage evolution curves. Furthermore, an equation for the estimation of fatigue strength was derived under the assumption that fatigue failure occurs when the damage variable reaches to a critical value. When compared the experimental S-N data of scarf joints with the estimated ones, the estimated fatigue strengths agree well with the experimental data with various scarf angles. This finding suggests that the CDM model is applicable for estimating fatigue strength of adhesively bonded joints with different stress triaxialities.


1992 ◽  
Vol 114 (3) ◽  
pp. 344-352 ◽  
Author(s):  
S. Tanary ◽  
Y. M. Haddad ◽  
A. Fahr ◽  
S. Lee

This paper is concerned with the use of the acousto-ultrasonic technique to evaluate nondestructively the mechanical performance of composite bonded joints. In this context, acousto-ultrasonic measurements followed by destructive shear tests were performed on single lap joint specimens made from graphite/epoxy adherends joined with FM 300 film adhesive. The results indicate a good correlation between acousto-ultransonic wave propagation characteristics and the shear strength of the bonded joints under different testing conditions. These correlations suggest that an estimation of the joint strength can be made by using acousto-ultrasonics provided that the measurement system is calibrated for variations of the material and geometry of the specimen.


1988 ◽  
Vol 16 (3) ◽  
pp. 146-170 ◽  
Author(s):  
S. Roy ◽  
J. N. Reddy

Abstract A good understanding of the process of adhesion from the mechanics viewpoint and the predictive capability for structural failures associated with adhesively bonded joints require a realistic modeling (both constitutive and kinematic) of the constituent materials. The present investigation deals with the development of an Updated Lagrangian formulation and the associated finite element analysis of adhesively bonded joints. The formulation accounts for the geometric nonlinearity of the adherends and the nonlinear viscoelastic behavior of the adhesive. Sample numerical problems are presented to show the stress and strain distributions in bonded joints.


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