PREDICTION OF VIBRATION DAMPING PROPERTIES OF POLYMER-LAMINATED STEEL SHEET USING TIME TEMPERATURE SUPERPOSITION PRINCIPLE

The vibration damping properties of the polymer-laminated steel sheet have been investigated theoretically and experimentally. The laminate consisted of a polymer layer, which was sandwiched between two steel sheets. Two polymers, a polyvinyl butyral and a copolymer of ethylene and acrylic acid, were used. The theoretical analysis was based on a model proposed by Ungar. A frequency analyzer was used to measure the loss factor of the laminate. The model required rheological data, such as storage modulus G' and loss tangent of the polymer at high frequency, which could not be obtained from commercially available dynamic rheometers. The time-temperature superposition principle was applied to the laminated polymer to construct the master curves of G' and loss tangent vs. frequency. These master curves provided rheological data at high frequency, which were superposed from data measured at low temperature. The results showed that a discrepancy existed between the loss factors predicted with superposed and without superposed data and the reasons for this discrepancy were discussed. The measured loss factors of the laminates at high frequency followed the predictions using superposed data, but not for those measured at low frequency. Factors accounting for this deviation were analyzed. The results also indicated that, in general, the transition temperature of the polymer-laminated steel sheet was 15-degrees-C-30-degrees-C higher than the corresponding glass transition temperature of the laminated polymer.