Journal of Adhesion

Romanko, John; Knauss, W. G.

doi: 10.1080/0021846808544633pmid: N/A

In order to provide quantitative information for the viscoelastic stress analysis of polymer-bonded structural joints, the time or rate sensitivity of Poisson's ratio for a structural adhesive FM-73M is examined. The experimental method is based on holographic interferometry. It is found that for times in the glassy-to-rubbery range, Poisson's ratio remains constant even though measurable creep occurs in the same time domain.

Adam, T.; Evans, J. R. G.; Packham, D. E.

doi: 10.1080/0021846808544634pmid: N/A

By use of a blowing agent bubbles of a few hundred microns diameter were introduced at the interface of copper and steel substrates coated with low density polyethylene. The presence of the bubbles leads to an improvement in peel strength. An explanation is put forward in terms of a suggested stress perturbation produced by the bubbles which leaves the interface itself relatively lowly stressed and leads to the expenditure of work in plastic deformation of the polymer away from the interface. Support for the explanation was obtained by photoelastic study of a model system and by scanning electron microscopy of the peeled surfaces.

Thomas, Graham H.; Rose, Joseph L.

doi: 10.1080/0021846808544635pmid: N/A

The problem of predicting adhesive bond performance for both surface preparation and undercure defects has been studied using an ultrasonic, experimental test bed system. This experimental test bed incorporates the ultrasonic and computer equipment necessary to acquire and process data from various types of adhesively bonded test specimens. The computer hardware and software has been developed to allow the design of reliable pattern recognition algorithms for the evaluation of surface preparation and bond cure. The specific problem studied is the inspection of the adhesive bond in an aluminum to aluminum step-lap joint whose strength could be affected by improper surface preparation or undercure. A set of 154 bond specimens was used to design an algorithm that is 91% reliable for separating the specimens into a good class, those bonds with no defects, or a weak class, bonds with poor surface preparation or undercured adhesive layer. A Fisher Linear Discriminant function was selected by the test bed as the best pattern recognition routine for this classification problem.

Peretz, D.; Ishai, O.

doi: 10.1080/0021846808544636pmid: N/A

The mechanical behavior of an adhesive layer was characterized by a specially designed torsion-tension device which yields the shear moment displacement relationship at different levels of axial load. The derived failure envelope shows an increase in shear strength with increasing axial compression, and the opposite under tension. Small changes of the shear modulus were also observed.

doi: 10.1080/00218468008544637pmid: N/A