A Novel Notion of Local and Nonlocal Deformation-Gamuts to Model Elastoplastic Deformation

Localization and nonlocalization are characterized as a measure of degrees of separation between two material points in material’s discrete framework and as a measure of unshared and shared information, respectively, manifested as physical quantities between them, in the material’s continuous domain. A novel equation of motion to model the deformation dynamics of material is proposed. The shared information between two localizations is quantified as nonlocalization via a novel multiscale notion of Local and Nonlocal Deformation-Gamuts or DG Localization and Nonlocalization. Its applicability in continuum mechanics to model elastoplastic deformation is demonstrated. It is shown that the stress–strain curves obtained using local and nonlocal deformation-gamuts are found to be in good agreement with the Ramberg–Osgood equation for the material considered. It is also demonstrated that the cyclic strain hardening exponent and cyclic stress–strain coefficient computed using local and nonlocal deformation-gamuts are comparable with the experimental results as well as the theoretical estimations published in the open literature.

Form finding in elastic gridshells

Elastic gridshells comprise an initially planar network of elastic rods that are actuated into a shell-like structure by loading their extremities. The resulting actuated form derives from the elastic buckling of the rods subjected to inextensibility. We study elastic gridshells with a focus on the rational design of the final shapes. Our precision desktop experiments exhibit complex geometries, even from seemingly simple initial configurations and actuation processes. The numerical simulations capture this nonintuitive behavior with excellent quantitative agreement, allowing for an exploration of parameter space that reveals multistable states. We then turn to the theory of smooth Chebyshev nets to address the inverse design of hemispherical elastic gridshells. The results suggest that rod inextensibility, not elastic response, dictates the zeroth-order shape of an actuated elastic gridshell. As it turns out, this is the shape of a common household strainer. Therefore, the geometry of Chebyshev nets can be further used to understand elastic gridshells. In particular, we introduce a way to quantify the intrinsic shape of the empty, but enclosed regions, which we then use to rationalize the nonlocal deformation of elastic gridshells to point loading. This justifies the observed difficulty in form finding. Nevertheless, we close with an exploration of concatenating multiple elastic gridshell building blocks.

THE NONLINEAR AND NONLOCAL INTEGRABLE SINE‐GORDON EQUATION

A new type of the nonlocal sine‐Gordon equation with the generalized interaction term is suggested. Its limit cases, symmetries and exact analytical solutions are obtained. This type of the nonlocal sine‐Gordon equation is shown to possess one‐, two‐ and N‐solitonic solutions which are a nonlocal deformation of the corresponding classical solutions of the sine‐Gordon equation. Pasiūlyta nauja nelokali sine‐Gordono evoliucine lygtis su apibendrintu saveikos nariu. Nustatyti šios lygties ribiniai atvejai, Lagranžianas, simetrijos, tikslūs analiziniai sprendiniai. Parodyta, kad šios rūšies nelokali sine‐Gordono lygtis turi vieno, dvieju bei N‐solitoninius sprendinius, kurie yra atitinkamu klasikiniu sine‐Gordono lygties sprendiniu nelokalios deformacijos. Nelokalios sine‐Gordono lygties integruojamumas siejamas su geometrinemis dvimačiu nelokaliai deformuotu paviršiu savybemis.

POINT PARTICLE IN GENERAL BACKGROUND FIELDS AND FREE GAUGE THEORIES OF TRACELESS SYMMETRIC TENSORS

Point particle may interact with traceless symmetric tensors of arbitrary rank. Free gauge theories of traceless symmetric tensors are constructed, which provides a possibility for a new type of interactions, when particles exchange by those gauge fields. The gauge theories are parametrized by the particle's mass m and otherwise are unique for each rank s. For m=0, they are local gauge models with actions of 2s th order in derivatives, known in d=4 as "pure spin," or "conformal higher spin" actions by Fradkin and Tseytlin. For m≠0, each rank-s model undergoes a unique nonlocal deformation which entangles fields of all ranks, starting from s. There exists a nonlocal transform which maps m≠0 theories onto m=0 ones, however, this map degenerates at some m≠0 fields whose polarizations are determined by zeros of Bessel functions. Conformal covariance properties of the m=0 models are analyzed, the space of gauge fields is shown to admit an action of an infinite-dimensional "conformal higher spin" Lie algebra which leaves gauge transformations intact.