No abstract

No abstract

No abstract

Numerical solution to the problem of the springback of thick wall tubes is investigated with consideration of nonlinear kinematic hardening model. Also, the effects of different types of loading and their sequences on the springback of these pipes have been investigated. In the employed approach in this research, the precision of the springback forecast has increased, which will reduce the cost and time for assembly of materials. Considering the effects of loading, it is possible to take steps to reduce springback. In addition, the problem is simulated by finite element method, in addition to modeling this problem, its results can be used to validate the numerical solution of the problem. It is shown when the bending loading rate increases, the bending springback angle decreases and with increasing torsional loading rate compared to the bending loading, the torsional springback angle decreases. Also, by changing the loading sequence, for example, bending and then fixing the bending radius and increasing the torsional angle (torsional loading) can significantly reduce bending springback angles.

The existence of landscape constraints in the home range of living organisms that adopt Lévy-flight movement patterns, prevents them from making arbitrarily large displacements. Their random movements indeed occur in a finite space with an upper bound. In order to make realistic models, by introducing exponentially truncated Lévy flights, such an upper bound can thus be taken into account in the reaction-diffusion models. In this work, we have investigated the influence of the λ-truncated fractional-order diffusion operator on the spatial propagation of the epidemics caused by infectious diseases, where λ is the truncation parameter. Analytical and numerical simulations show that depending on the value of λ, different asymptotic behaviours of the travelling-wave solutions can be identified. For small values of λ (λ≳0), the tails of the infective waves can decay algebraically leading to an exponential growth of the epidemic speed. In that case, the truncation has no impact on the superdiffusive epidemics. By increasing the value of λ, the algebraic decaying tails can be tamed leading to either an upper bound on the epidemic speed representing the maximum speed value or the generation of the infective waves of a constant shape propagating at a minimum constant speed as observed in the classical models (second-order diffusion epidemic models). Our findings suggest that the truncated fractional-order diffusion equations have the potential to model the epidemics of animals performing Lévy flights, as the animal diseases can spread more smoothly than the exponential acceleration of the human disease epidemics.