Hot tension programming

Figure 5.12 Thermomechanical behavior of SMPFs by both cold and hot tension programmings, (a) Stress-strain-time diagram for Sample 2. Steps 1 to 5 complete programming and Step 6 completes stress recovery, where step 1 is to stretch the fiber bundle to 100% strain at a rate of200 ram/min at 100 °C step 2 is to hold the strain constant for 1 hour step 3 is to cool the fiber to room temperature slowly while holding the pre-strain constant step 4 is to release the fiber bundle from tbe fixture (unloading) step 5 is to relax the fiber in the stress-free condition until the shape is fixed and step 6 is to recover the fiber at 150 °C in the fully constrained condition (adapted from Reference [20]) (b) Stress-strain-time diagram for Sample 3. Steps 1-4 complete programming and step 5 completes stress recovery, where step 1 is to stretch the fiber bundle to 100% strain at a rate of 200 mm/min at room temperature step 2 is to hold the strain constant for 1 hour step 3 is to release the fiber bundle from fixtures (unloading) step 4 is to relax the fiber in the stress-free condition until the shape is fixed and step 5 is to recover the fiber at 150 °C in the fully constrained condition (adapted from Reference [20]) (c) Stress evolution with time for Sample 2 (d) Stress evolution with time for Sample 3.

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