Thermo-magnetic control system for nano-ferromagnetic particle doped shape memory alloy for orthopedic devices and rehabilitation techniques

Abstract

This paper introduces a control mechanism targeting mechatronic devices by use of thermomagnetic loading instead of thermal loading for the proposed nano-ferromagnetic doped porous Shape Memory Alloy (SMA). The proposed material is formed by doping nano-ferromagnetic particle into porous NiTi alloy, an example of SMA. The Computer Aided design (CAD) and corresponding finite element analysis of shape memory effect (SME) property of the different distribution of nanoferromagnetic particle are done and compared against the same load and boundary conditions. The comparative analysis of the percentage change in the volume deformation in finite element analysis for SME when load is released (for 2nd step) shows an average of 2.55% with standard deviation of 1.69 whereas on thermal loading (for 3rd step) shows an average of 94.94% with standard deviation of 7.75 for all heterogeneous distribution of nano-particles in porous NiTi alloy. Thus, all the distribution of nano-ferromagnetic doped porous NiTi show SME property. For the proof of concept demonstration of the mechatronic device using the proposed SMA, an experiment is designed using a bimetallic strip, microcontroller, sensor and feedback circuitry system. It is observed that for the supply of 4 V and bent angle for flex sensor between 0 to 45 degree, current through the solenoid is 3.63 A producing magnetic field of 1.42 mT and for flex sensor bent angle 45 to 55 degree the current through the solenoid is 1.2 A producing magnetic field of 0.47 mT for same supply and if the flex sensor bent angle increases more than 55 degree then the voltage supply cuts off indicating absence of magnetic field substantiating the claim of controllability.