Adhesive tape is capable of supporting relatively large shear stress, but it is not able to support significant tensile stress. In this problem, you will measure the shear strength of a piece of tape. Refer to Figure P5.19.

(a) Cut about a dozen segments of tape having identical length L and width b. The exact length isn’t important, but the segments should be easily handled.

(b) Develop a means to apply and measure the pull force F on the tape. Use, for instance, dead weights (cans of soda or exercise weights) or a small fishing scale.

(c) Attach a segment of tape to the edge of a table, with only a portion of tape adhering to the surface. In your tests, consider attachment lengths ranging between a fraction of an inch and several inches.

(d) Being careful to apply the pull force straight along the tape, measure the value F necessary to cause the adhesive layer to slide or shear off the table. Tabulate pull force data for a half dozen different lengths a.

(e) Make graphs of pull force and shear stress versus a. From the data, estimate the value of the shear stress above which the tape will slide and come loose from the table.

(f) At what length a did the tape break before it sheared off the table?

(g) Repeat the tests for the orientation in which F is applied perpendicular to the surface, tending to peel the tape instead of shearing it. Compare the tape’s strengths for shear and peeling.

Figure P5.19

Transcribed Image Text:

a Adhesive layer F JF