Variation in Functional Properties of Shape Memory Materials under Use of Long Duration

形状记忆材料长期使用后功能特性的变化

基本信息

批准号：
13650104
负责人：
TOBUSHI Hisaaki
金额：
$ 2.37万
依托单位：
Aichi Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

项目摘要

In the present study, functional properties of shape memory alloy (SMA) and shape memory polymer (SMP), fatigue properties of SMA and deformation properties of SMP held at the fixed shape for a long duration were investigated. The results obtained can be summarized as follows.(1)In the subloop loading of SMA under the stress-controlled conditions, stress relaxation under constant strain and creep deformation under constant stress appear in the loading process. Stress recovery and creep recovery appear in the unloading press. These pseudoviscoelastic behaviors are induced due to the martensitic transformation based on variation in temperature.(2)An alternating-plane bending fatigue testing machine for an SMA wire was newly developed. The influence of strain ratio on fatigue life is systematically expressed by using maximum strain for rotating-bending, pulsating-plane bending and alternating-plane bending fatigue of an SMA wire. Fatigue life of a newly developed superelastic thin-walled … More tube is shorter than that of a wire. Fatigue crack of a thin tube initiates on an inner surface. The ratio of fracture surface due to fatigue in a thin tube is small.(3)With respect to a newly developed highelastic thin wire, the stress-strain curve is almost straight till a stress level of 1400 MPa and an amount of strain of 4%. The fatigue property does not depend on temperature and frequency. Modulus of elasticity is one fourth of that of stainless steel. The highelastic thin wire has high performance for a medical guide wire.(4)If an SMP foam is loaded at high temperature and the deformed shape is held at low temperature, both ratios of shape fixity and shape recovery are larger than 98 % without depending on maximum strain after holding for six months.(5)If the deformed shape of an SMP foam is held at high temperature, secondary shape forming occurs, resulting in imperfect shape recovery. The ratio of shape irrecoverableness increases in proportion to shape-holding temperature, shape-holding strain and shape-holding time. Less

在本研究中，研究了形状记忆合金（SMA）和形状记忆聚合物（SMP）的功能性能，SMA的疲劳特性以及长期持续时间保持在固定形状的SMP的变形特性。（1）在应力控制条件下SMA的司孔载荷中，获得的结果可以汇总。（1）在压力控制条件下，在恒定应变下的应力松弛和在恒定应力下出现在载荷过程中。压力恢复和蠕变恢复出现在卸载压中。由于温度变化，由于马氏体变化而引起了这些假弹性行为。（2）新开发了SMA线的替代平面弯曲疲劳测试机。应变比对疲劳寿命的影响通过使用最大应变来进行旋转弯曲，脉动平面弯曲和SMA线的替代平面弯曲疲劳。新开发的超弹性薄壁的疲劳寿命……比电线更短。细管的疲劳裂纹在内表面启动。薄管中由于疲劳而导致的断裂表面的比率很小。（3）对于新开发的高质细线，应力 - 应变曲线几乎是笔直的，直到应力水平为1400 MPa，量为4％。疲劳特性不取决于温度和频率。弹性模量是不锈钢的四分之一。（4）如果在高温下加载了SMP泡沫，并且在低温下保持形状的形状，则形状固定性和形状恢复的比率大于98％，而不是持续六个月后的最大压力，如果固定后的最大应变，则在六个月后的最大应变。形状不正确的比例与形状持有温度，形状持续应变和形状持续时间的比例增加。较少的