A characterization of frequency–temperature–prestress effects in viscoelastic films

Viscoelastic materials can be used to design efficient damping treatments. The design of well-damped structures typically requires significant numerical optimizations which rely on proper material characteristics. The present study was motivated by applications where an initially flat viscoelastic sandwich is press formed. Constitutive laws, that gave good correlation for the flat plate, led to poor correlation in bent configurations. It is well known that the properties significantly depend on frequency, temperature but also on other environmental factors such as static prestress. None of the classical techniques being suited to the determination of static prestress effects, a new test rig allowing dynamic measurement of complex shear modulus of a thin film under significant static loading was thus needed. The design and experimental validation of this rig are presented, and some results on the characterization of frequency–temperature–prestress effects in a sandwich plate and their representation using the superposition hypothesis are discussed.