Theoretical and experimental evaluation of the bond strength under peeling loads

Journal Article · Wed Oct 01 04:00:00 EDT 1997 · Journal of Engineering Materials and Technology

DOI:https://doi.org/10.1115/1.2812278· OSTI ID:543522

Nayeb-Hashemi, H; Jawad, O C ^[1]

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1. Northeastern Univ., Boston, MA (United States). Dept. of Mechanical Industrial and Manufacturing Engineering

Reliable applications of adhesively bonded joints require understanding of the stress distribution along the bond-line and the stresses that are responsible for the joint failure. To properly evaluate factors affecting peel strength, effects of defects such as voids on the stress distribution in the overlap region must be understood. In this work, the peel stress distribution in a single lap joint is derived using a strength of materials approach. The bonded joint is modeled as Euler-Bernoulli beams, bonded together with an adhesive, which is modeled as an elastic foundation which can resist both peel and shear stresses. It is found that for certain adhesive and adherend geometries and properties, a central void with the size up to 50% of the overlap length has negligible effect on the peak peel and shear stresses. To verify the solutions obtained from the model, the problem is solved again by using the finite element method and by treating the adherends and the adhesive as elastic materials. It is found that the model used in the analysis not only predicts the correct trend for the peel stress distribution but also gives rather surprisingly close results to that of the finite element analysis. It is also found that both shear and peel stresses can be responsible for the joint performance and when a void is introduced, both of these stresses can contribute to the joint failure as the void size increases. Acoustic emission activities of aluminum-adhesive-aluminum specimens with different void sizes were monitored. The AE ringdown counts and energy were very sensitive and decreased significantly with the void size. It was observed that the AE events were shifting towards the edge of the overlap where the maximum peeling and shearing stresses were occurring as the void size increased.

• Sponsoring Organization: USDOE
• OSTI ID: 543522
• Journal Information: Journal of Engineering Materials and Technology, Journal Name: Journal of Engineering Materials and Technology Journal Issue: 4 Vol. 119; ISSN 0094-4289; ISSN JEMTA8
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ACOUSTIC EMISSION TESTING
ADHESIVES
ALUMINIUM BASE ALLOYS
COMPOSITE MATERIALS
CORRELATIONS
EPOXIDES
EXPERIMENTAL DATA
FINITE ELEMENT METHOD
JOINTS
MATHEMATICAL MODELS
MECHANICAL PROPERTIES
STRESSES
THEORETICAL DATA
VOIDS