以非接触式形状记忆合金平面涡卷弹簧为例,研究了此类元件的作动原理,建立了镍钛形状记忆合金涡卷弹簧的力学模型.以普通平面涡卷弹簧的计算方式和形状记忆合金的相变方程本构模型为基础,建立了形状记忆合金涡卷弹簧的力学模型,获得了预紧扭力、激励温度、输出扭力和转角位置之间的关系表达式,并且通过两组测试验证了该力学模型和关系表达式.在对激励温度和扭力输出的关系测试中,模型计算值对测试值的确定系数为0.669,最小误差为2.4%,最大误差为215.9%;在对转角位移和扭力的关系测试中,计算值与测试值的确定系数为0.336,最小误差为48.9%,最大误差为350.0%.测试显示,力学模型的计算值与测试的数据具有类似的表征形式.
By taking non-contact nitinol Shape Memory Alloy(SMA) spiral springs for examples,this paper explores the activer principle of this kinds of spiral springs and estallishes a mechanical model for the spiral springs.On the basis of the calculation method of an ordinary plane spiral spring and the constitutive model of phase transformation equation for the SMA,a mechanical model of SMA spiral spring was established,and the relationship among the preload,motivate temperature,output torsion and the angular displacement was obtained.Then,the mechanical model was validated by practical measurements.In the temperature and torsion relationship testing,the coefficient of determination between test value and calculated value is 0.669,the minimum error rate is 2.4% and the maximum error rate is 215.9%.In the angular displacement and torsion relationship testing,the coefficient of determination between test value and calculated value is 0.336,the minimum error rate is 48.9% and the maximum error rate is 350.0%.The results show that the test results and calculated value have the similar form of representation.