Irreducible representation of surface distributions and Piola transformation of external loads sustainable by third gradient continua
In this paper Piola transformations are found that relate the Eulerian and Lagrangian external loads which third gradient continua can sustain. As shown by Gabrio Piola and Paul Germain, the most effective postulation scheme in mechanics is based on the principle of virtual work and therefore contin...
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Académie des sciences
2023-04-01
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| Series: | Comptes Rendus. Mécanique |
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| Online Access: | https://comptes-rendus.academie-sciences.fr/mecanique/articles/10.5802/crmeca.157/ |
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| author | dell’Isola, Francesco Fedele, Roberto |
| author_facet | dell’Isola, Francesco Fedele, Roberto |
| author_sort | dell’Isola, Francesco |
| collection | DOAJ |
| description | In this paper Piola transformations are found that relate the Eulerian and Lagrangian external loads which third gradient continua can sustain. As shown by Gabrio Piola and Paul Germain, the most effective postulation scheme in mechanics is based on the principle of virtual work and therefore continuum mechanics must be mathematically founded based on the theory of distributions and on differential geometry. Using the principle of virtual work, the set of admissible external loads sustainable by third gradient continua is seen to include: i) volume force density, ii) surface density of contact force, iii) surface density of contact double force, iv) surface density of contact triple force, v) line density of edge contact forces, vi) line density of contact edge double forces and vii) contact forces concentrated on wedge points. Following the nomenclature introduced by Paul Germain, forces are dual in virtual work of virtual displacements, surface and line double forces are dual of the derivatives of virtual displacements in the normal direction(s) of the surfaces and edges constituting the boundary of the continuum, and surface triple forces are dual of the second normal derivatives of virtual displacements. Volume and surface forces transform as in first gradient Cauchy continua. Moreover we find that: a) the virtual work expended by Eulerian surface triple force, when transformed into the Lagrangian description, must be represented as the work expended by all the kinds of external Lagrangian loads listed in i)-vii); b) Eulerian surface double force transforms into Lagrangian surface double force, surface contact force and edge contact line force; c) Eulerian edge contact line double force transforms into Lagrangian edge contact line double forces, edge line forces and point concentrated wedge forces; d) Eulerian edge and wedge contact line forces transforms into their Lagrangian counterpart only. The Piola transformation formulas deduced in this paper depend on the first, second and third gradients of placement. The presented results allow for the formulation of well-posed boundary condition problems for third gradient continua in the Lagrangian description, and are relevant in computational mechanics. In view of the obtained Piola transformation formulas, the concept of dead loads needs to be modified. We believe to have given an example of how the Mechanics in the French Style, as developed on the ideas by D’Alembert and Lagrange, is still a fertile tool of invention. |
| format | Article |
| id | doaj-art-4385fa6a339d4ed7b30fcb83739b3fc1 |
| institution | Kabale University |
| issn | 1873-7234 |
| language | English |
| publishDate | 2023-04-01 |
| publisher | Académie des sciences |
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| series | Comptes Rendus. Mécanique |
| spelling | doaj-art-4385fa6a339d4ed7b30fcb83739b3fc12025-02-07T13:47:59ZengAcadémie des sciencesComptes Rendus. Mécanique1873-72342023-04-01351S39112010.5802/crmeca.15710.5802/crmeca.157Irreducible representation of surface distributions and Piola transformation of external loads sustainable by third gradient continuadell’Isola, Francesco0https://orcid.org/0000-0002-3607-1113Fedele, Roberto1https://orcid.org/0000-0003-1057-9581Department of Civil, Construction-Architectural and Environmental Engineering (DICEAA), University of L’Aquila, Piazzale Ernesto Pontieri, Monteluco di Roio, 67100 L’Aquila, and International Research Center on Mathematics and Mechanics of Complex Systems (MEMOCS), University of L’Aquila, L’Aquila, Italy.Department of Civil and Environmental Engineering (DICA), Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan, Italy.In this paper Piola transformations are found that relate the Eulerian and Lagrangian external loads which third gradient continua can sustain. As shown by Gabrio Piola and Paul Germain, the most effective postulation scheme in mechanics is based on the principle of virtual work and therefore continuum mechanics must be mathematically founded based on the theory of distributions and on differential geometry. Using the principle of virtual work, the set of admissible external loads sustainable by third gradient continua is seen to include: i) volume force density, ii) surface density of contact force, iii) surface density of contact double force, iv) surface density of contact triple force, v) line density of edge contact forces, vi) line density of contact edge double forces and vii) contact forces concentrated on wedge points. Following the nomenclature introduced by Paul Germain, forces are dual in virtual work of virtual displacements, surface and line double forces are dual of the derivatives of virtual displacements in the normal direction(s) of the surfaces and edges constituting the boundary of the continuum, and surface triple forces are dual of the second normal derivatives of virtual displacements. Volume and surface forces transform as in first gradient Cauchy continua. Moreover we find that: a) the virtual work expended by Eulerian surface triple force, when transformed into the Lagrangian description, must be represented as the work expended by all the kinds of external Lagrangian loads listed in i)-vii); b) Eulerian surface double force transforms into Lagrangian surface double force, surface contact force and edge contact line force; c) Eulerian edge contact line double force transforms into Lagrangian edge contact line double forces, edge line forces and point concentrated wedge forces; d) Eulerian edge and wedge contact line forces transforms into their Lagrangian counterpart only. The Piola transformation formulas deduced in this paper depend on the first, second and third gradients of placement. The presented results allow for the formulation of well-posed boundary condition problems for third gradient continua in the Lagrangian description, and are relevant in computational mechanics. In view of the obtained Piola transformation formulas, the concept of dead loads needs to be modified. We believe to have given an example of how the Mechanics in the French Style, as developed on the ideas by D’Alembert and Lagrange, is still a fertile tool of invention.https://comptes-rendus.academie-sciences.fr/mecanique/articles/10.5802/crmeca.157/Third-gradient materialsPrinciple of Virtual WorkPiola TransformationEulerian descriptionLagrangian descriptionDistribution theoryDifferential Geometry |
| spellingShingle | dell’Isola, Francesco Fedele, Roberto Irreducible representation of surface distributions and Piola transformation of external loads sustainable by third gradient continua Comptes Rendus. Mécanique Third-gradient materials Principle of Virtual Work Piola Transformation Eulerian description Lagrangian description Distribution theory Differential Geometry |
| title | Irreducible representation of surface distributions and Piola transformation of external loads sustainable by third gradient continua |
| title_full | Irreducible representation of surface distributions and Piola transformation of external loads sustainable by third gradient continua |
| title_fullStr | Irreducible representation of surface distributions and Piola transformation of external loads sustainable by third gradient continua |
| title_full_unstemmed | Irreducible representation of surface distributions and Piola transformation of external loads sustainable by third gradient continua |
| title_short | Irreducible representation of surface distributions and Piola transformation of external loads sustainable by third gradient continua |
| title_sort | irreducible representation of surface distributions and piola transformation of external loads sustainable by third gradient continua |
| topic | Third-gradient materials Principle of Virtual Work Piola Transformation Eulerian description Lagrangian description Distribution theory Differential Geometry |
| url | https://comptes-rendus.academie-sciences.fr/mecanique/articles/10.5802/crmeca.157/ |
| work_keys_str_mv | AT dellisolafrancesco irreduciblerepresentationofsurfacedistributionsandpiolatransformationofexternalloadssustainablebythirdgradientcontinua AT fedeleroberto irreduciblerepresentationofsurfacedistributionsandpiolatransformationofexternalloadssustainablebythirdgradientcontinua |