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A device is described that excites individual modes of the standing wave spectrum for surface waves on water in a water tank of rectangular cross section. By synchronizing the downward acceleration of the tank with the standing wave on the water, Rayleigh-Taylor instabilities with reproducible characteristics are excited at the air-water interface. By controlling the width of the tank, the fluid motion is made to be largely two dimensional. The reproducibility of the phenomenon and the two-dimensional character of the flow make it possible, for the first time, to compare details of the wave profile with results predicted with the two-dimensional models of Emmons, Chang, and Watson.

Experiments are performed to determine the impact of several physical properties on the creep behavior of three different sets of corrugated containers subjected to static loading and a cyclic humidity environment ranging from 50% to 80% relative humidity in a 24 h period. One sample set had basis weights of the fl uted medium varied from 68 to 205 g/m 2 while keeping the basis weight of the linerboard facings at 205 g/m 2 . This varied the out-of-plane shear rigidity of the single wall board by a factor of three. Another set of corrugated samples investigated effects of lateral or linear corrugating by rotation of either linerboards, fl uted medium or both. This equalizes hygroexpansivity and affects lifetime. A third series of boxes had barrier coatings applied to their surfaces to determine the effect on lifetime. Creep and lifetime are determined to be inversely related and a multiple regression model for lifetime was sought based on the data set. Homogenization of the corrugated board properties through either increased medium basis weight or component rotation (lateral or linear corrugating) and application of barrier coating will in general, increase the endurance of edge loaded corrugated board in cyclic humidity. C-fl ute and exposed to 50% RH or 90% RH. Bronkhorst 15 more recently showed that lifetime (L) can be predicted from the secondary creep rate (dε/dt) through the relationship: 192 R. E. POPIL AND B. HOJJATIE 25. Peterson WS, Schimmelpfenning WJ. Panel edge boundary conditions and compressive strengths of tubes and boxes. Tappi Journal 1975; 65(8): 108-110. 26. Morgan DG. A mechanistic creep model and test procedure. Appita Journal 2003; 57(4): 543-549. 27. Whitsitt WJ. Papermaking factors affecting box properties. Tappi Corrugated Container Conference; 1988: 163-167. 28. Brodeur PH, Hutten IM, Jonakin JL. MD and CMD properties of linerboard components and the resulting box compressive strength. Tappi Journal 1997; 80(10): S27-S35.

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