The test methods for vibration-damping property in damping steel sheets of constrained type with high damping-factor

In most cases, the conventional method (called center exciting method) has used for evaluation of damping steel sheets of constrained type. However, it has come to our attention that the method has often resulted in a high damping factor. Investing a new evaluation method for vibration damping property of steel sheets, work was carried out to measure a free vibration in attenuating generated to oscillate a resonance frequency to a test peace and then, calculate damping factor for it with the measurement result by a theological formula. Indication was made that the damping factors obtained by this scheme was always lower than those calculated based on a transfer function by the conventional method. As a conclusion, it was realized that a considerable margin of error affected the difference between the results given by the evaluation methods. The new method we tried assures stable attenuation vibration from the first mode to a higher mode; thus securing more accurate calculation of the damping factor.