Computational Physics Group
Analysis of tongue and groove joints for thick laminates
K. Matous and George J. Dvorak
Department of Mechanical Engineering, Aeronautical Engineering and Mechanics
Rensselaer Polytechnic Institute
110 8th Street, Troy, NY 12180
A finite element evaluation of local stresses in the
adhesive and adherends is presented for a tongue-and-groove joint of a
homogenized thick composite laminate to steel plate. The
quasi-isotropic laminate is made of glass fabric/vinyl ester
plies. Most results are obtained for elastic response of the
Dexter-Hysol 9338 adhesive that was used in recent experiments
(Dvorak, G.J., Zhang, J. and Canyurt, O., ``Adhesive Tongue and Groove
Joints for Thick Composite Laminates'', Composites Science and
Technology, 61, 1123-1142 (2001)). A nonlinearly
viscoelastic adhesive is also considered, with illustrative properties
taken from experiments on the FM-73 system. Both in-plane force
resultants and out-of-plane moments are included in the applied
loads. Scaling of the elastic results with regard to plate thickness
shows that for given levels of overall stresses applied to the
adherend plates, the stresses supported by the adhesive do not depend
on plate thickness. Adhesive stress relaxation is shown to be
relatively small, and occurring in a short time period.
The results illustrate the stress distributions encountered in
adhesive tongue and grove joints of thick laminated composite plates.
As in other joint configurations, the stress concentrations at the
adhesive leading edge depend on the local geometry of the adherends.
However, for given values of stresses in plate sections removed from
the joint, the stresses in the joint remain independent of a plate
thickness. This is a significant advantage that does not hold in
conventional lap joints, and thus favors use of tongue and grove
joints of different configurations in joining of thick laminates,
where the unavoidable stress concentrations at the adhesive leading
edge can be amply supported by the high in-plane strength of the
laminated plate. Consideration of the viscoelastic response of the
adhesive indicates a relatively small relaxation of the local
stresses, within a fairly short time period.
The authors appreciate financial support of this work by the Ship
Structures and Systems S&T Division of the Office of Naval
Research. Dr. Yapa D.S. Rajapakse served as program monitor.
© 2009 Notre Dame and Dr. Karel Matous