4923

4627

كارشناسي ارشد

طراحي كاربردي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مكانيك

1388

سيزده، [129] ص: مصور، جدول، عكس، نمودار

ص.ع.به: فارسي و انگليسي

محمود سليمي، محمود كدخدايي

21/10/88

عليرضا شهيدي، محمد مشايخي

مهندسي مكانيك

ID4627

به فارسي و انگليسي: قابل رويت در نسخه ديجيتال

Investigation on Thermomechanical Behavior of SMA Wires Iman Mohagheghian Iman mohagheghian@gmail com Date of Submission July 9 2009 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiDr Mahmoud Salimi salimi@cc iut ac irDr Mahmoud Kadkhodaei kadkhodaei@cc iut ac irAbstractIn the last decades smart materials especially Shape Memory Alloys SMA s have attracted specialattention as these materials can make an appropriate solution for the most of engineering problems Nowadays SMA s are widely used in many engineering fields including biomechanics aerospace civil and robotics applications One of the most important applications of SMA s is in the field ofactuators For predicting the SMA actuators an appropriate model that can consider all of the SMA scomplexities is needed Firstly a 1 D Electro Thermo Mechanical model is proposed for actuator applications This model within the continuum mechanics framework can predict shape memory effect pseudoelacticity strainrate dependency and longitudinal variation of parameters The problems considered in the previousworks for complicated thermomechanical paths are solved in this model The proposed model isevaluated in 4 common conditions in SMA actuators Then the effective factors in the time responseof SMA actuators are investigated Results show that the supposed model of free convective heattransfer has a great effect in the final response and that considering the convective heat transfercoefficient as a constant number may not be a good assumption Comparing to equations obtained byenergy balance deriving the governing equations in the continuum mechanics framework would leadto obtain some additional expressions Results show that neglecting these terms can lead to a wrong prediction for SMA actuators The second part corresponds to experimental works Because of the complexities existing in thebehavior of shape memory alloys prediction of SMA response needs several material parameterswhich should be obtained by accurate tests Firstly a proper procedure to access transformationtemperatures is suggested Secondly a thermal chamber is designed and manufactured for performingdifferent thermomechanical tests This chamber can be mounted on different tensile tests machinesand can be used for carrying out mechanical tests in the specified temperatures By performing severalthermomechanical tests the necessary parameters for the proposed model are extracted for the bothNiTi samples Keywords Shape memory alloy Electro Thermo Mechanical model SMA actuators DSC tests Thermal chamber Thrermo Mechanical tests

محمود سليمي، محمود كدخدايي

عليرضا شهيدي، محمد مشايخي