Vibrations and self-heating of a layered elastic-viscoelastic rectangular prism under a vibrating punch

Abstract

The vibrations and self-heating of a layered metal-polymer rectangular prism kinematically excited by a normally vibrating punch are analyzed numerically. The effect of reinforcement layers on the rate of variation in and the spatial distribution of the temperature field is examined. It is established that thin metallic layers in a polymer matrix change the dissipation mechanism from shear to bulk. The effect of contact stress concentration on the localization of temperature field is studied. It is established that the energy flux through the load application area decreases due to softening of the material. Several reinforcement effects are revealed. It is shown that they are determined by the value of the load parameter. The numerical results are in good agreement with experimental data on self-heating kinetics Keywords: viscoelastic material, vibrations, heating, layered prism Introduction. Research of the vibrations and self-heating of viscoelastic bodies is of theoretical and practical importance for the evaluation of the fatigue strength of polymer and rubber-metal members [2,5,15] and for the development of efficient polymer processes such as ultrasonic welding of plastics and their composites [3].Self-heating models for linear and nonlinear viscoelastic bodies are substantiated in numerous studies [10-12, 17, 21]; their results are systematized in [5,8,9,20]. An analysis of experimental and theoretical studies [13,17,21] shows that the thermomechanical behavior of inelastic bodies under harmonic loading is well described in terms of complex moduli [13,14,16,18]. The major results in this subject area were obtained for homogeneous viscoelastic bodies. The thermomechanical state of bodies with stress concentrators such as cylindrical inclusions and notches was studied in [6,7].Of current importance are viscoelastic laminated composites intended to sustain intensive cyclic loading. The contribution of the distortion and bulk strain energies to the stored and dissipated energies of a disk with polymer layers of different thickness under isothermal cyclic compression was assessed in [18,19]. This paper uses the theory of coupled thermoviscoelasticity [5] to study the vibrations and self-heating of a rectangular prism with polymer and metal layers under normal high-frequency load exerted by a vibrating rectangular punch. The layers are made of polyethylene and copper. The problem posed will be solved numerically, modeling the prism by a piecewise-inhomogeneous body with temperature-dependent properties.

Vibration and dissipative heating of a layered rectangular viscoelastic prism under harmonic shear loading

“…Materials Properties. We used the temperature-dependent physical and mechanical properties of PE from [9,10]. The volumetric losses are calculated using the equality ¢¢ ¢ = ¢¢ ¢ K K G G / / c , which was experimentally established in the isothermal case in [16] for a number of polymers, including PE.…”

“…Also, of practical importance are laminated viscoelastic composites used to make products to be subjected to intensive cyclic loading. The relationship between the accumulated and dissipated distortion and dilatation energies for different thicknesses of polymeric layers in a layered disk under isothermal quasistatic compression is analyzed in [20,21].Vibration, vibrational heating, and thermal instability of a layered rectangular metal-polymer prism under normal harmonic loading are addressed in [10].Structural members and technological objects such as layered thin parts may be subject to high-frequency shear loading during ultrasonic welding. Such a loading is specific in that mainly the distortion energy is dissipated.…”

“…Vibration, vibrational heating, and thermal instability of a layered rectangular metal-polymer prism under normal harmonic loading are addressed in [10].…”

Thermal instability of a layered rectangular viscoelastic prism under high-frequency compressive loading

“…The vibrational heating of a layered metal-polymer prism under high-frequency loading was studied in [1,2]. It was established that bulk losses should be taken into account in evaluating the dissipation rate in thin polymeric layers compressed between metallic layers.…”

Using a split Hopkinson bar to specify the parameters of thermomechanical models of flow under high strain rate deformation

“…The coupling of mechanical and thermal fields is of theoretical and applied importance. While in service, many structural elements of modern engineering are subjected to cyclic or impulsive loads, which may induce inelastic residual strains and temperature changes, either reversible (thermoelastic) or irreversible (dissipative) [12,13,30]. Monotonic quasistatic, high strain rate, and very high strain rate loading may give rise to local regions of large inelastic strains and high temperature (thermal shear bands) [22,23,25,28], which may lead to failure.…”