- #1
scott_alexsk
- 336
- 0
Hello,
I was curious about any thoughts any of you might have concerning an interesting result I found today. While I was annealing a 32 cm wire of nitinol at about 300 C, which for its diameter is about 1 amp, I noticed that when the wire was made less tense, it moved up and down systematically. I noticed if I blew on the wire, making it cold, it tensed up and the effect temporarily disappeared. The effect also went away when I decreased the amperage a couple hundreths or increased the tension.
When my teacher and I looked at the wire more closely, besides moving up and down systematically about 4 millimeters, for 32 cm of wire, the wire seemed to bunch up forming a continuous standing wave. The best we could think to explain it is that since 300 C is the minimum temperature at which nitinol can be annealed, changing air currents or changing the amperage, decreased it below that certain threshold. The waves we believe were caused by the fact that we had an AC generator right below the sample on the counter, generating the one amp.
Even with this explanation though, certain descrepancies remain. The wire for one moved systematically up and down, and to a lesser extent side to side, besides having the apparent standing wave. I am going to go back tommorrow and test it at a location further away from the AC generator to see if there is a change, but I would appreciate any comments on possible reasons for this effect.
Thanks,
-scott
I was curious about any thoughts any of you might have concerning an interesting result I found today. While I was annealing a 32 cm wire of nitinol at about 300 C, which for its diameter is about 1 amp, I noticed that when the wire was made less tense, it moved up and down systematically. I noticed if I blew on the wire, making it cold, it tensed up and the effect temporarily disappeared. The effect also went away when I decreased the amperage a couple hundreths or increased the tension.
When my teacher and I looked at the wire more closely, besides moving up and down systematically about 4 millimeters, for 32 cm of wire, the wire seemed to bunch up forming a continuous standing wave. The best we could think to explain it is that since 300 C is the minimum temperature at which nitinol can be annealed, changing air currents or changing the amperage, decreased it below that certain threshold. The waves we believe were caused by the fact that we had an AC generator right below the sample on the counter, generating the one amp.
Even with this explanation though, certain descrepancies remain. The wire for one moved systematically up and down, and to a lesser extent side to side, besides having the apparent standing wave. I am going to go back tommorrow and test it at a location further away from the AC generator to see if there is a change, but I would appreciate any comments on possible reasons for this effect.
Thanks,
-scott