Abstract

Shape memory effect is the key factor in the design of self-reconfigurable core using origami. Effects of heat treatment on transformation temperatures and stress-strain curve of shape memory alloys using differential scanning calorimetry and tensile testing is presented. Moreover, vibration of pre/post-buckled sandwich beam with self-deployable shape memory alloy (SMA) core and SMA wires reinforced hybrid composite faces is investigated. The Boyd and Lagoudas SMA constitutive model is utilized in ABAQUS UMAT subroutine. Extensive numerical studies presented for pre-strain, volume fraction, location, time and temperature of heat treatment depends on the properties of SMA fibers, along with core and hybrid composite temperature dependency. As can be seen from results, vibration behaviors, thermal stability and total thickness of self-foldable sandwich structure can be efficiently controlled by adjusting the values of SMA wires volume fraction, pre-strain and core type, respectively. Mechanical properties of SMA are decreased, as a result of increase in heat treatment time and temperature. Increasing heat treatment temperature leads to lower transformation temperatures of SMA. In contrast, higher transformation temperatures are the results of increasing heat treatment time.

摘要

形状记忆效应是使用折纸设计自重构磁芯的关键因素。使用差示扫描量热法和拉伸试验，介绍了热处理对形状记忆合金转变温度和应力-应变曲线的影响。此外，还研究了具有自展开形状记忆合金 (SMA) 芯和 SMA 线增强混合复合材料面的预/后屈曲夹层梁的振动。Boyd 和 Lagoudas SMA 本构模型用于 ABAQUS UMAT 子程序。对热处理的预应变、体积分数、位置、时间和温度进行了广泛的数值研究，这取决于 SMA 纤维的特性，以及芯和混合复合材料的温度依赖性。从结果可以看出，振动行为，通过分别调整 SMA 线材体积分数、预应变和芯线类型的值，可以有效地控制自折叠夹层结构的热稳定性和总厚度。由于热处理时间和温度的增加，SMA的机械性能下降。提高热处理温度会降低 SMA 的转变温度。相反，更高的转变温度是增加热处理时间的结果。