Rheological Aspects of Multilayered Thick-Wall Polymeric Pipes under the Influence of Internal Pressure

Abstract

Rheologic of a polymer pipe from cyclic temperature and internal pressure in one-dimensional and two-dimensional formulations is considered. The resulting equations of the finite element method allow one to calculate both single-layer and multilayer thick-walled pipes taking into account creep. In the calculation, the temperature dependences of the elastic and rheological parameters of polymer pipes were used. The effect of variable thermal conditions on the VAT of a PVC pipe is investigated. It has been established that under unsteady thermal conditions, stresses can occur significantly higher than in a stationary temperature field. This is explained by the fact that polymers have a component of deformation that is lagging in phase from stresses (highly elastic deformation).

Stress-strain state of concrete filled steel tubular columns of annular cross-section taking into account physical nonlinearity

“…The resulting equation coincides with the main resolving equation for the case of a plane deformed state of the cylinder [8]. Equation ( 9) is solved numerically by the finite difference method.…”

Processing of Polymers Stress Relaxation Curves Using Machine Learning Methods

“…Finding the quantities 𝑚 * and 𝜂 0 * at the same time is associated with certain difficulties, since the theoretical creep and relaxation curves using the Maxwell-Gurevich equation cannot be described by analytical functions. Some algorithms for determining these quantities are presented in papers [11][12][13] . The disadvantage of these algorithms is the high quality requirements for experimental curves.…”