Improving the vibration characteristics of a 2DOF system by using an improved damper made of shape memory alloys.

In this study, the vibrational behavior of two-degree-of-freedom damping systems is investigated through experimental and theoretical work using different damping components. Shape memory alloy (SMA) dampers, springs, and different types of steel springs are added to 2DOF to modify the response of that system. The equations of motion for the system are derived from the principles of Newton's second law of motion. In the first studied case, stainless steel springs were used in the system, and the values of natural frequency explained the effect of the stiffness variations of those springs on the vibrational characteristics of the 2DOF system. The second studied case focused on utilizing the Shape Memory Alloy springs, the unique properties of SMAs, and the high difference between the stiffness values in martensite and austenite phases in influencing the vibration behavior of the 2DOF system. The systematic variations in SMA stiffness highlighted their distinct impact on natural frequencies. Additionally, mass variations were explored, indicating a clear dependency between mass distribution and system dynamics. The results show that the increase in the stiffness of stainless steel springs (K1 and K2) from 0.4886 N/mm to 0.88779 N/mm and the Nitinol spring (KSMA) from 0.049424 N/mm to 0.076549 N/mm leads to a significant increase in natural frequencies—approximately 16% and 57% for stainless steel springs and 45% for the Nitinol spring. Conversely, elevating the values of the first mass, m1, from 0.30 kg to 0.50 kg, and the second mass, m2, from 0.35 kg to 0.550 kg, results in a decrease in natural frequencies—approximately 33%, 10%, 39%, and 1% across different cases for m1, and 14%, 26%, 2%, and 35% for m2, showcasing a clear correlation between increased masses and softened system dynamics. Finally, the results offer comprehensive insights into the dynamic behavior of the damped 2-DOF system, emphasizing the significance of material properties and mass distribution in controlling system vibrations. [ABSTRACT FROM AUTHOR]