scholarly journals Towards the solution of creep problems of thin-shelled tubular elements in isotropic nonlinear viscoelastic materials

2019 ◽  
pp. 42-45
Author(s):  
V. P. Golub
Keyword(s):  
Creep Strain ◽  
Viscoelastic Properties ◽  
Volumetric Strain ◽  
Combined Loading ◽  
Strain Intensity ◽  
Viscoelastic Materials ◽  
One Dimensional ◽  
Nonlinear Viscoelastic ◽  
Nonlinear Viscoelastic Materials ◽  
Transverse Strains

A new approach to the creep strains analysis of thin-shelled tubular elements in isotropic nonlinear viscoelastic materials under combined loading with uniaxial tension and torsion has been proposed. The system of equations that is constructed according to the deviators proportionality hypothesis has been chosen as the creep constitutive equations the nonlinearity of viscoelastic properties in which is given with respect to the creep strain intensity and volumetric strain by the Rabotnov type models. The kernels of creep strain intensity and volumetric strain are given by the relations that establish the relationships between these kernels and one-dimensional creep kernels determined from a system of base experiments. One-dimensional tension with the measurement of longitudinal and transverse strains as well as one-dimensional tension and pure torsion with the measurement of longitudinal and shearing strains have been considered as base experiments. The functions of nonlinearity of viscoelastic properties are given by smoothing cubic splines. The problems of the analysis of longitudinal, transverse and shearing strains of thin-shelled tubular specimens made of “high density polyethylene PEHD” have been solved and experimentally approved.

scholarly journals To the problem of influence of the third invariant of stress deviator on the process of longterm deformation of nonlinear viscoelastic materials

2019 ◽  
pp. 186-189
Author(s):  
A. V. Romanov ◽  
P. V. Fernati
Keyword(s):  
Experimental Data ◽  
Stressed State ◽  
Physical And Mechanical Properties ◽  
Combined Loading ◽  
Stress Deviator ◽  
Nonlinear Creep ◽  
Viscoelastic Materials ◽  
Third Invariant ◽  
Nonlinear Viscoelastic ◽  
Nonlinear Viscoelastic Materials

The problem on the influence of stressed state on the process of long-term deformation of nonlinear viscoelastic materials under the simple and quasi-simple modes of loading by introduction of the function with the parameter of Lode angle into the defining equations is considered. The mentioned function is determined by analysis of base experimental data obtained from the base experiments on axial tension and pure torsion. Physical and mechanical properties of nonlinear viscoelastic solids are defined by the correspondence between the invariants of deformation tensors and tensions according to the modified nonlinear Rabotnov’s model for viscoelasticity. The heredity kernels are given by the fractional-exponential function. The constructed defining equations are verified experimentally for the problems of determination of nonlinear creep deformations under combined loading applied to the thin-walled tubular elements made of polyethylene of high density and low pressure polyethylene. As a result of juxtaposition of experimental data and calculations it is a stated that allowing for the type of stressed state improves their agreement qualitatively and quantitatively.

scholarly journals Magnetic resonance elastography in nonlinear viscoelastic materials under load

2018 ◽  
Vol 18 (1) ◽  
pp. 111-135 ◽  
Author(s):  
Adela Capilnasiu ◽  
Myrianthi Hadjicharalambous ◽  
Daniel Fovargue ◽  
Dharmesh Patel ◽  
Ondrej Holub ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Magnetic Resonance Elastography ◽  
Viscoelastic Materials ◽  
Nonlinear Viscoelastic ◽  
Nonlinear Viscoelastic Materials

Initial Value Problems in Viscoelasticity

1988 ◽  
Vol 41 (10) ◽  
pp. 371-378 ◽  
Author(s):  
W. J. Hrusa ◽  
J. A. Nohel ◽  
M. Renardy
Keyword(s):  
Classical Solutions ◽  
Linear Wave ◽  
Time Behavior ◽  
Initial Value ◽  
One Dimensional ◽  
Nonlinear Viscoelastic ◽  
Linear Wave Propagation ◽  
Long Time ◽  
Nonlinear Viscoelastic Materials ◽  
Time Existence

We review some recent mathematical results concerning integrodiff erential equations that model the motion of one-dimensional nonlinear viscoelastic materials. In particular, we discuss global (in time) existence and long-time behavior of classical solutions, as well as the formation of singularities in finite time from smooth initial data. Although the mathematical theory is comparatively incomplete, we make some remarks concerning the existence of weak solutions (i e, solutions with shocks). Some relevant results from linear wave propagation will also be discussed.

Sign in / Sign up

Export Citation Format

Share Document