Confined shape recovery

In order to understand the thermomechanical cycle of the syntactic foam under different test conditions better, the test results are presented in both 3-D and 2-D format. Typical 2-D axial stress-time and temperature-time curves for the foam confined by the nylon liner, programmed at 79 °C, and under 60% pre-strain level, and fully confined shape recovery are shown in Figure 3.29. Typical 3-D axial stress-axial strain-ternperamre thermomechanical cycles for the syntactic foam at a programming ternperamre of 71 °C, pre-strain level of 30%, and fully confined shape recovery are shown in Figure 3.30. Typical 3-D axial stress-axial strain-time behaviors at a programming temperature of 79 °C, pre-strain level of 30%, and fully confined shape recovery are shown in Figure 3.31. 

It is noted that in a recent review paper by Hu et al. [8], self-healing using the shape memory effect (SME) has been divided into two categories. One is unconfined shape recovery and the other is confined shape recovery. Rodriguez, Luo, and Mather [52] studied a blend system consisting of a cross-linked poly(e-caprolactone) network (n-PCL) with linear poly(e-caprolactone) (1-PCL) interpenetrating the network, which exhibited a combination of shape memory response from the... 

The compression after impact (CAI) test was conducted to evaluate the residual strength after impact and the healing efficiency after confined shape recovery. Previous studies [70,71] have... 

Mechanism for Confined shape recovery by Constrained shape recovery by resisting... 

Figure 3.9 Setup used for isothermal stress-strain testing and constrained shape recovery testing. The fixture provided a 1-D external confinement and the furnace was used to trigger the shape memory effect by heating the specimen above its Tg. The MTS machine was used to record the resuiting recovery stress...

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