Optimized Adhesive Performance in Electronic Transportation Sign Construction

Monday, January 17, 2022 - 15:30

The ultimate objective of this project was to determine the structural performance of the dynamic message sign (DMS) bonded with chemical adhesive in terms of ultimate strength and fatigue strength. To achieve this objective, this project first investigated the effects of various parameters (i.e., conditioning humidity and conditioning temperature) on tensile, shear, peel, and cleavage strength through small-scale tests of adhesive specimens with variations in specimen width. Numerous data resulting from the tests were analyzed through graphical comparisons and statistical analysis to explore the effect of the considered parameters on each of the strengths. It was found that conditioning humidity and width were the most significant parameters negatively affecting the tensile and peel strength, respectively. Four full-scale DMS tests were also performed to examine their structural performance. Specifically, the ultimate strength testing was carried out on one DMS with adhesive joints and one with typically welded connections, and the fatigue testing was also conducted for one DMS system with adhesive joints and one with welded connections. The ultimate strength testing demonstrated that the adhesive DMS failed at 125 kN, while the weld DMS failed at 146 kN. During the fatigue test, stress ranges observed in the panel were much below the threshold of the DMS' aluminum panel. No sign of damage was observed in either adhesive or welded DMSs from the fatigue tests. The results indicated that a DMS with adhesively bonded connections is relatively better than welded DMS with respect to the stress induced in the panel. This project report is available from the Upper Great Plains Transportation Institute web site at https://www.ugpti.org/resources/reports/details.php?id=1050&program=mpc


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