- A Piece Of Scotch Tape Is Glued To A Table And We Wish To Determine Its Adhesive Strength For This We Peel The Tape 1 (9.25 KiB) Viewed 32 times
The act of peeling consists of moving the "peeling point" s = a to a displaced position s = a-da, which leads to the debonding of the tape over a length da. a) Argue why the total bending energy stored in the tape is not changed during the displacement by da. Make us of a drawing like in the figure. b) Estimate the work done SR by the vertical external force during the dis- placement da. c) Given that the bending energy does not change, argue that this energy went into the debonding of the adhesive. Why is f a good measure for the adhesive strength? Unfortunately we do not have a force-sensor available, but we can de- termine the peeling force by measuring the tape-curvature at s = a from a photo. This requires a bit of analysis. d) Consider the discussion around Figure 11 in the Lecture Notes (dictaat): demonstrate the shape of the tape is governed by the functional 1 E = [ds L(0,0), with L=B0¹² - f sin 0. e) When does not depend explicitly on s, we can show that the Euler- Lagrange equation can be simplified to: ƏL L(0,0¹) - 0' = C₁ (9) 20' where C is a constant. This is known as Beltrami identity. Use it to find the equation for 8(s). f) Determine the constant C, and express the peeling force in terms of the curvature at the peeling front (0' at s = a).