Influence of heating rate on evolution of dynamic properties of polymeric laminates

Abstract

The most common description of the mechanical behaviour of viscoelastic materials is presented using complex dynamic properties. These properties depend on many external factors (temperature, excitation frequency, etc.) and determine the evolution of derivative effects in the structure. The purpose of the conducted investigations is the determination of the influence of heating rate on the dynamic mechanical behaviour of a polymer based composite material under different excitation frequencies and temperatures. The glass transition temperatures and the activation energies of the phase transition were calculated, which allow extending the Arrhenius equation by the heating rate factor. The obtained dependencies could be useful for the estimation of the mechanical and thermal degradations of polymeric composites and, among others, for the determination of the self-heating temperature distributions and their evolution during cyclic loading. The presented results could also be applied for the determination of fatigue, crack growth and residual life of composite structures.

Evolution of Static and Dynamic Properties of Gfrp Laminates during Ageing in Deionized and Seawater

“…Such a conclusion can be made during the comparison of values of E and Rm for the specimens before ageing. As it was stated in [12], the initial Young modulus for the investigated composite equalled 24204 MPa, while the ultimate tensile strength equalled 413 MPa. A possible reason of lack of any trend in values is the equilibration between the described processes.…”

A Study of the Thermal Runaway Phase Generated During Cyclic Loading of Viscoelastic Materials Accounting for the Prestress

“…Although heat transfer analyses of elastomers has been already conducted by some other authors (Katunin, 2012;Katunin and Gnatowski, 2012;Kirichok, 2013;Lesieutre and Mingori, 1990), the contribution intended for the present study is to investigate the degradation in stiffness and damping capacity of viscoelastic materials due to the thermal runaway phase induced by cyclic loadings superimposed on static preloads. Also, by comparing the obtained results with those appearing in the open literature, the following features are to be highlighted: (i) the thermal-viscoelasticmechanical modeling as presented here can be applied to more complex viscoelastic systems due to the formulation of a complete strain state; (ii) the effects of the static preloads on the thermal runaway phase and its effects on the stiffness degradation and damping capacity of the viscoelastic material is also considered as contribution; (iii) in view of practical applications by using the available commercial FE codes from the engineering perspective, it was performed a harmonic prestressed analyses to take into account the static preloads superimposed on the dynamic excitations; (iv) an optimization problem has been formulated in order to identify the unknown thermal parameters describing the experimental scenarios.…”

Fatigue and Thermal Failure of Polymeric Composites Subjected to Cyclic Loading

“…The fibre content in the manufactured composite comprised of 30% of the whole weight. Strength properties of an investigated composite were obtained in experiments [16] and have values as follows: tensile strength of 413 MPa, flexural modulus of 24.2 GPa, flexural strength of 633.2 MPa. The specimens prepared for tests were cut to the following dimensions: thickness of 2.5±0.2 mm, width of 10 mm and four variants of effective length (i.e.…”

“…The conception of theoretical model of fatigue considering self-heating effect was presented in [15]. The research presented in [16] show, that the composite stiffness and degradation ability is determined not only by excitation frequency and temperature, but also by the heating rate -the time when the temperature stabilized. Considering all findings presented of above-cited works the authors decided to investigate experimentally the process of fatigue considering self-heating effect.…”