( O / ^. I /J.IAi< rtcaa,.c. <.L kts.c.-.": -',9 APPLETON, WISCONSIN THE INSTITUTE OF PAPER CHEMISTRY,

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1 I /J.IAi< t... t 0%,.4.- ' rtcaa,.c. <.L kts.c.-.": -',9 ( O / ^. Initte of Paper Science and Technology Central Files THE INSTITUTE OF PAPER CHEMISTRY, APPLETON, WISCONSIN FAILURE OF CORRUGATED BOXES UNDER LONG TERM LOADING- SUMMARY OF RESULTS AS OF JUNE, 963 / Project Report One A Preliminary Report to TECHNICAL COMMITTEE OF THE FOURDRINIER KRAFT BOARD INSTITUTE, INC. June 3, 963

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3 TABLE OF CONTENTS Page INTRODUCTION Materials DISCUSSION OF RESULTS Box Creep Tests Combined Board Creep Tests LITERATURE CITED

4 THE INSTITUTE OF PAPER CHEMISTRY Appleton, Wisconsin FAILURE OF CORRUGATED BOXES UNDER LONG TERM LOADING- SUMMARY OF RESULTS AS OF JUNE, 963 INTRODUCTION It may be - recalled that the Fourdrinier Kraft Board Institute has initiated a study of the creep or storage characteristics of corrugated boxes. The purpose of this study is to predict the box stacking (long-time) performance from a knowledge of the creep characteristics of the combined board via the present equations for top load box compression. The experimental program involves determination of the creep characteristics of (a) corrugated boxes in compression subjected to various dead loads, and (b) combined board subjected to edgewise compression and flexural stresses. MATERIALS Fifteen box samples have been received as described in Table I. A number of additional samples were received too late for inclusion in the table. The top load compression results for a number of the samples are shown in Table II. I

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6 Technical Committee Fourdrinier Kraft Board Institute, Inc. Page 3 Project Report One DISCUSSION OF RESULTS BOX CREEP TESTS Equipment has been built to permit simultaneous testing of twentyfour boxes. In general, it is planned to evaluate four boxes from each box sample at four ratios of applied load to top load box compression strength. These ratios are: 0.50, 0.55, 0.65, and Based on the work of Kellicutt and Landt (), these applied load ratios should result in average failure times of approximately 300, 85, 4, and 0.6 days. The results obtained to date are summarized in Tables III and IV in terms of failure life and deflection prior to failure, respectively. It may be noted that a. At 0.75 load ratio average times to failure ranged from 0.38 to.3 days for the three A-flute Samples 406, 407, and 456. Thus, it appears that the average time to failure will be considerably greater than the expected value of 0.6 days based on Reference (). b. At the lower load ratios, it also appears that longer average failure lives will be obtained. For example, all four boxes from Sample 407 at 0.55 ratio have survived 4 days whereas the expected average would be 85 days. c. Box deflections near creep failure are about equal to those obtained in the conventional top load compression test. I With regard to (a) and (b) above, it may be noted that the results in Reference () were based on tests involving one B-flute and one or more solid

7 Technical Committee Page 4 Fourdrinier Kraft Board Institute, Inc. Report One Project fiber samples. More recently Kellicutt suggests that considerably longer creep failure lives for A-flute and double-wall boxes may be obtained. This would be more in line with the results in Table III. If additional tests continue to confirm this trend, the load ratios selected above will be revised to give more practical time periods. TABLE III SUMMARY OF BOX CREEP RESULTS Applied Speci- Failure Time, days Load men Sample Sample Sample Sample Sample Sample Ratio No over over 65 over 60 3" 3 over " 85 over over 3 over " ( over over I

8 Technical Committee Fourdrinier Kraft Board Institute, Inc. Project Page 5 Report One TABLE IV COMPARISON OF BOX CREEP DEFLECTIONS PRECEDING FAILURE WITH MAXIMUM DEFLECTION IN THE BOX COMPRESSION TEST Deflection, inch Sample Sample Sample Sample Sample Sample Max. deflection (box compression test), inch o.93 Creep failure defl., inch a 0.75 load ratio load ratio o load ratio athe creep failure deflection is defined box deflection prior to box collapse. as the last recorded value of the

9 Technical Committee Page 6 Fourdrinier Kraft Board Institute, Inc. Report One Project COMBINED BOARD CREEP TESTS On the assumption that the edgewise compression strength of combined board is the dominant factor in box compression under creep conditions as well as in short-term tests, attention has been directed to developing a column creep test. In a later phase, the creep behavior of combined board in flexure will be studied. A prototype model of a column creep tester has been constructed and found to perform satisfactorily. It is anticipated that several additional testers will be constructed in the near future, incorporating a number of simplifications, several improvements and some additional deflection and time-measuring devices. A limited amount of column creep data have been obtained for Sample 407, as shown in Table V. The tests have been restricted thus far to the higher load ratios, leading to short duration times. At the present time there are insufficient box creep data and column creep data for this sample to enable drawing conclusions as to the relationship between box and combined board creep performance.

10 Technical Committee Fourdrinier Kraft Board Institute, Inc. Project Page 7- Report One TABLE V PRELIMINARY DATA ON COLUMN CREEP BEHAVIOR OF COMBINED BOARD FROM SAMPLE 407 Applied Load Ratio a Specimen No. Failure Time, days o Test in progress, 46 days aedgewise compression strength = 4. Ib./in.

11 I Page 8 Report One Technical Committee Fourdrinier Kraft Board Institute, Inc. Project LITERATURE CITED. Kellicutt, K. Q., and Iandt, E. F. Basic design data for use of fibreboard in shipping containers. Forest Products Laboratory Report No. 9, Sept., 958. THE INSTITUTE OF PAPER CHEMISTRY Will J. Whtsitt Research Aide, Container Section < /c^w 4 C4 Robert C. McKee, Chief Container Section

Strength criterion for corrugated fiberboard under long-term stress

PEER REVIEWED FIBERBOARD TESTING Strength criterion for corrugated fiberboard under long-term stress THOMAS J. URBANIK HEN CORRUGATED BOXES with their contents are stacked and subjected to long-term storage,