The tape underwent expansion... that is it rose up..... That adjusted the extra increased length.
Since the friction force for the radial expansion is toooo large...... as the friction is along the complete length. But along perpendicular direction.. force of friction is very less... So naturally when subjected to heat... The increased length inside would generate strain in both direction : Radial as well as Perpendicular... Bcoz of reason explained above.. it finally tends to move in normal direction. And Once MOved in that direction... It will go on moving along that(Not even backward..) as frictional force goes on decreasing with increased expansion...
Hi, As you have mentioned, the expansion caused the rise. But when the tape would have been subjected to heat the expansion would have been possible in both the directions. (as you also mentioned). Friction in this case is governed by adhesive force (ryt) which would also have been affected by heat. So when the outer most layer experienced expansion , then it was constrained by frictional force. But there are three directions, radial, axial(perpendicular) and circumferential (theta , in terms of cylindrical co ordinates). I agree that in radial since there are so many loops of tape, the adhesive force was str0ng enough to prevent its expansion radially, but then what about circumferential. The open end (the end from where we open tape) would have experienced the least friction in theta direction than in axial. So it should have opened up or become scribbled.
The rise in single direction may be explained as follows: Since it was kept on cooler (or base) the only direction available for free expansion was up. However, another question that comes is, if it started rising. Initially the outer layers would have started to do so and then inner layers. Going By this way, the so called De-lamination (unwinding as shown in figures) should have been finer for outer layers than inner layers.
I am posting this on behalf of ritesh to maintain the flow/continuity of discussion at same place.
The expansion is alrite, since when heated expansion will be there and the radius if hole will increase. The mystery ( :) ) is there in tapering of , if i may call it. Now, we have to think that, there are 3 materials in the system 1. the tape, 2. the adhesive 3. the paper which is holding the tape, the base part. Every thing has different coeff of expansion and hence some weird shape after expansion. Then the question comes why the inner parts resolved more or were finely distributed than the outer, this may again be attributed to paper that is holding the tape and the inner layers which are more in contact with it. since, both have diff coeff of expansion(add to that melting of adhesive due to heat) the system got loose in the inner side only.
As per my clarification.... i would like to add I am not talking abt Radial.. But Only Circumferential and Normal. As i believe there wouldn't be any sort of Radial Expansion... The Only Expansion alond the plane possible is Circumferential( or Unwinding basically..) Friction to this expansion(Unwinding or Circumferential) is maximum due to adhesion force along the length. So Unwinding is impossible to max Case. But in all Length is increasing, so it has to undergo an expansion(to release it accumulated energy) Now i believe that both will be almost under same temperature. As per why it started from inside, not from outside... I would like to add Friction in the inner Layer will goes on decreasing as we move to centre. Max it outermost layer, least at innermost. And once it moved... the contact surface goes on decreasing, decreasing its friction and increasing the expansion.
The tape underwent expansion... that is it rose up..... That adjusted the extra increased length.
ReplyDeleteSince the friction force for the radial expansion is toooo large...... as the friction is along the complete length. But along perpendicular direction.. force of friction is very less... So naturally when subjected to heat... The increased length inside would generate strain in both direction : Radial as well as Perpendicular... Bcoz of reason explained above.. it finally tends to move in normal direction. And Once MOved in that direction... It will go on moving along that(Not even backward..) as frictional force goes on decreasing with increased expansion...
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ReplyDeleteHi,
ReplyDeleteAs you have mentioned, the expansion caused the rise. But when the tape would have been subjected to heat the expansion would have been possible in both the directions. (as you also mentioned). Friction in this case is governed by adhesive force (ryt) which would also have been affected by heat. So when the outer most layer experienced expansion , then it was constrained by frictional force. But there are three directions, radial, axial(perpendicular) and circumferential (theta , in terms of cylindrical co ordinates). I agree that in radial since there are so many loops of tape, the adhesive force was str0ng enough to prevent its expansion radially, but then what about circumferential.
The open end (the end from where we open tape) would have experienced the least friction in theta direction than in axial. So it should have opened up or become scribbled.
The rise in single direction may be explained as follows:
Since it was kept on cooler (or base) the only direction available for free expansion was up.
However, another question that comes is, if it started rising. Initially the outer layers would have started to do so and then inner layers. Going By this way, the so called De-lamination (unwinding as shown in figures) should have been finer for outer layers than inner layers.
I am posting this on behalf of ritesh to maintain the flow/continuity of discussion at same place.
ReplyDeleteThe expansion is alrite, since when heated expansion will be there and the radius if hole will increase. The mystery ( :) ) is there in tapering of , if i may call it. Now, we have to think that, there are 3 materials in the system
1. the tape,
2. the adhesive
3. the paper which is holding the tape, the base part.
Every thing has different coeff of expansion and hence some weird shape after expansion. Then the question comes why the inner parts resolved more or were finely distributed than the outer, this may again be attributed to paper that is holding the tape and the inner layers which are more in contact with it. since, both have diff coeff of expansion(add to that melting of adhesive due to heat) the system got loose in the inner side only.
As per my clarification.... i would like to add I am not talking abt Radial.. But Only Circumferential and Normal. As i believe there wouldn't be any sort of Radial Expansion... The Only Expansion alond the plane possible is Circumferential( or Unwinding basically..) Friction to this expansion(Unwinding or Circumferential) is maximum due to adhesion force along the length. So Unwinding is impossible to max Case.
ReplyDeleteBut in all Length is increasing, so it has to undergo an expansion(to release it accumulated energy)
Now i believe that both will be almost under same temperature.
As per why it started from inside, not from outside... I would like to add Friction in the inner Layer will goes on decreasing as we move to centre. Max it outermost layer, least at innermost.
And once it moved... the contact surface goes on decreasing, decreasing its friction and increasing the expansion.