Patents

The invention provide a Shape Memory Alloy (SMA) based composite repair device for repairing the composites which comprises: a mechanical screw rod (5a) being connected to top portion of a circular hub assembly (5b) by threaded screw (5c), top portion of the said circular hub assembly is connected to bottom portion of circular hub assembly (5d) by means of screw and nuts (5e), pluralities of Shape Memory Alloy (SMA) actuator elements (5f) are arranged between the said top and bottom hub assembly to ensure equidistance between force application points, said SMA actuator elements (5f) are electrically insulated from top and bottom hub assembly and from other SMA actuators using mica sheets (5g), the said mechanical screw is being provided with holding plate (5h) and nut (5i) for positioning the device during repair process. A software has been developed using Visual C++ compiler on Windows OS. A PID control algorithm is implemented in the software for realizing the closed loop temperature control of the annular ring. This algorithm accepts the instantaneous set value and actual temperature value. It runs the PID algorithm on these values and calculates the appropriate control output that will reduce the error.