Preload Influence on the Dynamic Properties of a Polyurethane Elastomeric Foam

Area of Science:

• Materials Science
• Mechanical Engineering
• Polymer Science

Background:

• Polymeric foams are crucial for vibration attenuation in engineering.
• Foam performance, particularly dynamic properties and attenuation, is preload-dependent.
• Understanding preload effects is key to optimizing foam applications.

Purpose of the Study:

• To experimentally characterize polyurethane elastomeric foam under varying preload, frequency, and temperature.
• To develop a predictive mathematical model for foam dynamic properties influenced by preload.
• To quantify the impact of preload on viscoelastic behavior and transition temperatures.

Main Methods:

• Dynamic Mechanical Analysis (DMA) was used for experimental characterization.
• Testing covered frequencies from 1 to 60 Hz, temperatures from -60 to 30 °C, and preloads from 2 to 12 N.
• A four-parameter fractional derivative model was fitted to experimental data to develop a seven-parameter model.

Main Results:

• Linear viscoelastic range increased by 57% with maximum preload.
• Storage modulus increased by 58% on average with preload; loss factor remained unaffected.
• Glassy transition temperature decreased with increased preload.

Conclusions:

• A seven-parameter mathematical model effectively describes frequency and preload effects on dynamic properties.
• Relaxation time, relaxed modulus, and unrelaxed modulus are dependent on the exponential of squared prestress.
• The fractional parameter showed no dependence on preload within the studied range.