Journal of Material Science and Mechanical Engineering (JMSME) Print ISSN: 2393-9095; Online ISSN: 2393-9109; Volume 2, Number 5; April-June, 2015 pp. 404-408 © Krishi Sanskriti Publications http://www.krishisanskriti.org/jmsme.html Shape Memory Composite as Actively Tuned Vibration Absorber Basavaraj Noolvi 1 , S. Raja 2 , Shanmukha Nagaraj 3 and Amith Kumar S N 4 1 Research Scholar, R V College of Engineering Acharya Institute of Technology, Bangalore 2 Scientist, National Aerospace Laboratories, Bangalore 3 Mechanical Engineering Department, R V College of Engineering, Bangalore 4 Mechanical Engineering Department, Dr. Ambedkar Institute of Technology, Bangalore E-mail: 1 braj.noolvi@gmail.com, 2 raja@css.nal.res.in, 3 shan.nagaraj@gmail.com, 4 amithkumar59@gmail.com Abstract—Shape memory materials (SMMs) are known for their excellent vibration absorption properties. The current work is focused on study of vibration absorption characteristics of Shape Memory Composites (SMCs), as tuned vibration absorber has been taken up. Thin cantilever plate of SAC works as the absorber system in the configuration. 1. INTRODUCTION A well-established vibration control device is the tuned vibration absorber (TVA). Even though such a device may be have different shapes it acts like a spring-mass system. For simplicity, a beam-like TVA can be used. One of the drawbacks of such a device, however, is that it can detune during operation because of changes in forcing frequency. To maintain its tuned condition a variable stiffness element is required so that the natural frequency of the absorber can be adjusted in real-time.A beam-like TVA has been realized using shape memory alloy (SMA) by Rustighi et al [1]. Such a material changes its mechanical properties with temperature. By varying the temperature of the beam the absorber can be tuned in order to maintain the vibration of the host structure to be very small. Many researchers studied vibration control using SMA. Baz et al. demonstrated SMA actuation capability to control the vibration frequencies of composite beams by activating optimal sets of embedded SMA wires [2]. The presented work focuses on the application of Smart adaptive composite (SAC) or shape memory composite (SMC) in active vibration control. 2. OVERVIEW OF TUNED VIBRATION ABSORBER None of the structures such as buildings, bridges, towers, or, machines or machine partsthat may be composedof many sub- assemblies can be made completely rigid [3]. They move in response to natural disturbances. In particular, every member has a set of special frequencies called natural frequencies, or resonance frequencies, at which it will respond particularly severely. When subjected to periodic forces at one of these natural frequencies, themember may respond with vibrations of amplitude large enough to affect the normal functioning of the member itself or its assembly or perhaps even dangerous to itself or to the assembly. If engineers expect a member to be subject to a periodic force at or near one of its natural frequencies, they may incorporate into its design a special device called a vibration absorber which is just a secondary spring mass system attached to the main system as shown in Fig. .(1). This is a device that suppresses vibration of the structure at one of its natural frequencies by transferring the energy that would cause such a vibration into vibration of a secondary mass. However complicated a system may bewe are concerned only with only oneof its natural frequencies, and hence it can be modeled as a spring masssystem whose resonant frequency is the troublesome natural frequency of the system. Moreover, though there can be any degree of sophistication in design, a tuned vibration absorber is in essence a secondary spring mass system attached to the primary system. Therefore the system (mass m 1 and spring constant k 1 ) coupled with tuned vibration absorber (mass m 2 and spring constant k 2 ) can be modeled using the coupled spring-mass system in Fig. 1.The system of differential equations describing the motion of such a spring mass system is given by,   1 1 1 1 2 1 2 1 sin mx kx k x x F t         2 2 2 2 1 mx k x x    (1.1) A particular solution of this system can be obtained by the method of undetermined coefficients for a single second order equation, in which x 1 , and x 2 are each of the form 1 2 sin cos c t c t    . But since there are no first order derivatives, and the second derivative of a sine function is still a sine function, we can simplify the solution in the form: 1 sin x A t   , 2 sin x B t   (1.2)