En résistance des matériaux, le module de cisaillement, module de glissement, module de rigidité, module de Coulomb ou second coefficient de Lamé, est une grandeur physique intrinsèque à chaque matériau et qui intervient dans la caractérisation des déformations causées par des efforts de cisaillement.
La définition du module de rigidité G {\displaystyle G} , parfois aussi noté μ, est G = df τ x y γ x y = F ℓ A Δ x , {\displaystyle G{\overset {\text{df)){=)){\dfrac {\tau _{xy)){\gamma _{xy))}={\frac {F\ell }{A\Delta x)),} où (voir l'image ci-contre) τ x y = F A {\textstyle \tau _{xy}={\frac {F}{A))} est la contrainte de cisaillement, F {\displaystyle F} la force, A {\displaystyle A} l'aire sur laquelle la force agit, γ x y = Δ x ℓ = tan ( θ ) {\textstyle \gamma _{xy}={\frac {\Delta x}{\ell ))=\tan(\theta )} le déplacement latéral relatif et θ {\displaystyle \theta } l'écart à l'angle droit, Δ x {\textstyle \Delta x} le déplacement latéral et enfin ℓ {\textstyle \ell } l'épaisseur.
Le module de rigidité G {\displaystyle G} , qui a la dimension d'une contrainte ou d'une pression, est généralement exprimé en mégapascals (ou newtons par millimètre carré) ou en gigapascals (ou joules par millimètre cube). À titre d'exemple, pour l'acier, G ≃ {\displaystyle G\simeq } 81 000 MPa = 81 GPa.
Dans le cas de matériaux isotropes, il est relié au module d'élasticité E {\displaystyle E} et au coefficient de Poisson ν {\displaystyle \nu } par l'expression : G = E 2 ( 1 + ν ) . {\displaystyle G={\dfrac {E}{2(1+\nu ))).}
formules en 3D
( λ , G ) {\displaystyle (\lambda ,G)}
( E , G ) {\displaystyle (E,G)}
( K , λ ) {\displaystyle (K,\lambda )}
( K , G ) {\displaystyle (K,G)}
( λ , ν ) {\displaystyle (\lambda ,\nu )}
( G , ν ) {\displaystyle (G,\nu )}
( E , ν ) {\displaystyle (E,\nu )}
( K , ν ) {\displaystyle (K,\nu )}
( K , E ) {\displaystyle (K,E)}
( M , G ) {\displaystyle (M,G)}
K [ P a ] = {\displaystyle K\,[\mathrm {Pa} ]=}
λ + 2 G 3 {\displaystyle \lambda +{\tfrac {2G}{3))}
E G 3 ( 3 G − E ) {\displaystyle {\tfrac {EG}{3(3G-E)))}
λ ( 1 + ν ) 3 ν {\displaystyle {\tfrac {\lambda (1+\nu )}{3\nu ))}
2 G ( 1 + ν ) 3 ( 1 − 2 ν ) {\displaystyle {\tfrac {2G(1+\nu )}{3(1-2\nu )))}
E 3 ( 1 − 2 ν ) {\displaystyle {\tfrac {E}{3(1-2\nu )))}
M − 4 G 3 {\displaystyle M-{\tfrac {4G}{3))}
E [ P a ] = {\displaystyle E\,[\mathrm {Pa} ]=}
G ( 3 λ + 2 G ) λ + G {\displaystyle {\tfrac {G(3\lambda +2G)}{\lambda +G))}
9 K ( K − λ ) 3 K − λ {\displaystyle {\tfrac {9K(K-\lambda )}{3K-\lambda ))}
9 K G 3 K + G {\displaystyle {\tfrac {9KG}{3K+G))}
λ ( 1 + ν ) ( 1 − 2 ν ) ν {\displaystyle {\tfrac {\lambda (1+\nu )(1-2\nu )}{\nu ))}
2 G ( 1 + ν ) {\displaystyle 2G(1+\nu )\,}
3 K ( 1 − 2 ν ) {\displaystyle 3K(1-2\nu )\,}
G ( 3 M − 4 G ) M − G {\displaystyle {\tfrac {G(3M-4G)}{M-G))}
λ [ P a ] = {\displaystyle \lambda \,[\mathrm {Pa} ]=}
G ( E − 2 G ) 3 G − E {\displaystyle {\tfrac {G(E-2G)}{3G-E))}
K − 2 G 3 {\displaystyle K-{\tfrac {2G}{3))}
2 G ν 1 − 2 ν {\displaystyle {\tfrac {2G\nu }{1-2\nu ))}
E ν ( 1 + ν ) ( 1 − 2 ν ) {\displaystyle {\tfrac {E\nu }{(1+\nu )(1-2\nu )))}
3 K ν 1 + ν {\displaystyle {\tfrac {3K\nu }{1+\nu ))}
3 K ( 3 K − E ) 9 K − E {\displaystyle {\tfrac {3K(3K-E)}{9K-E))}
M − 2 G {\displaystyle M-2G}
G [ P a ] = {\displaystyle G\,[\mathrm {Pa} ]=}
3 ( K − λ ) 2 {\displaystyle {\tfrac {3(K-\lambda )}{2))}
λ ( 1 − 2 ν ) 2 ν {\displaystyle {\tfrac {\lambda (1-2\nu )}{2\nu ))}
E 2 ( 1 + ν ) {\displaystyle {\tfrac {E}{2(1+\nu )))}
3 K ( 1 − 2 ν ) 2 ( 1 + ν ) {\displaystyle {\tfrac {3K(1-2\nu )}{2(1+\nu )))}
3 K E 9 K − E {\displaystyle {\tfrac {3KE}{9K-E))}
ν [ 1 ] = {\displaystyle \nu \,[1]=}
λ 2 ( λ + G ) {\displaystyle {\tfrac {\lambda }{2(\lambda +G)))}
E 2 G − 1 {\displaystyle {\tfrac {E}{2G))-1}
λ 3 K − λ {\displaystyle {\tfrac {\lambda }{3K-\lambda ))}
3 K − 2 G 2 ( 3 K + G ) {\displaystyle {\tfrac {3K-2G}{2(3K+G)))}
3 K − E 6 K {\displaystyle {\tfrac {3K-E}{6K))}
M − 2 G 2 M − 2 G {\displaystyle {\tfrac {M-2G}{2M-2G))}
M [ P a ] = {\displaystyle M\,[\mathrm {Pa} ]=}
λ + 2 G {\displaystyle \lambda +2G}
G ( 4 G − E ) 3 G − E {\displaystyle {\tfrac {G(4G-E)}{3G-E))}
3 K − 2 λ {\displaystyle 3K-2\lambda \,}
K + 4 G 3 {\displaystyle K+{\tfrac {4G}{3))}
λ ( 1 − ν ) ν {\displaystyle {\tfrac {\lambda (1-\nu )}{\nu ))}
2 G ( 1 − ν ) 1 − 2 ν {\displaystyle {\tfrac {2G(1-\nu )}{1-2\nu ))}
E ( 1 − ν ) ( 1 + ν ) ( 1 − 2 ν ) {\displaystyle {\tfrac {E(1-\nu )}{(1+\nu )(1-2\nu )))}
3 K ( 1 − ν ) 1 + ν {\displaystyle {\tfrac {3K(1-\nu )}{1+\nu ))}
3 K ( 3 K + E ) 9 K − E {\displaystyle {\tfrac {3K(3K+E)}{9K-E))}
formules en 2D
( λ 2 D , G 2 D ) {\displaystyle (\lambda _{\mathrm {2D} },G_{\mathrm {2D} })}
( E 2 D , G 2 D ) {\displaystyle (E_{\mathrm {2D} },G_{\mathrm {2D} })}
( K 2 D , λ 2 D ) {\displaystyle (K_{\mathrm {2D} },\lambda _{\mathrm {2D} })}
( K 2 D , G 2 D ) {\displaystyle (K_{\mathrm {2D} },G_{\mathrm {2D} })}
( λ 2 D , ν 2 D ) {\displaystyle (\lambda _{\mathrm {2D} },\nu _{\mathrm {2D} })}
( G 2 D , ν 2 D ) {\displaystyle (G_{\mathrm {2D} },\nu _{\mathrm {2D} })}
( E 2 D , ν 2 D ) {\displaystyle (E_{\mathrm {2D} },\nu _{\mathrm {2D} })}
( K 2 D , ν 2 D ) {\displaystyle (K_{\mathrm {2D} },\nu _{\mathrm {2D} })}
( K 2 D , E 2 D ) {\displaystyle (K_{\mathrm {2D} },E_{\mathrm {2D} })}
( M 2 D , G 2 D ) {\displaystyle (M_{\mathrm {2D} },G_{\mathrm {2D} })}
K 2 D [ N / m ] = {\displaystyle K_{\mathrm {2D} }\,[\mathrm {N/m} ]=}
λ 2 D + G 2 D {\displaystyle \lambda _{\mathrm {2D} }+G_{\mathrm {2D} ))
G 2 D E 2 D 4 G 2 D − E 2 D {\displaystyle {\tfrac {G_{\mathrm {2D} }E_{\mathrm {2D} )){4G_{\mathrm {2D} }-E_{\mathrm {2D} ))))
λ 2 D ( 1 + ν 2 D ) 2 ν 2 D {\displaystyle {\tfrac {\lambda _{\mathrm {2D} }(1+\nu _{\mathrm {2D} })}{2\nu _{\mathrm {2D} ))))
G 2 D ( 1 + ν 2 D ) 1 − ν 2 D {\displaystyle {\tfrac {G_{\mathrm {2D} }(1+\nu _{\mathrm {2D} })}{1-\nu _{\mathrm {2D} ))))
E 2 D 2 ( 1 − ν 2 D ) {\displaystyle {\tfrac {E_{\mathrm {2D} )){2(1-\nu _{\mathrm {2D} })))}
M 2 D − G 2 D {\displaystyle M_{\mathrm {2D} }-G_{\mathrm {2D} ))
E 2 D [ N / m ] = {\displaystyle E_{\mathrm {2D} }\,[\mathrm {N/m} ]=}
4 G 2 D ( λ 2 D + G 2 D ) λ 2 D + 2 G 2 D {\displaystyle {\tfrac {4G_{\mathrm {2D} }(\lambda _{\mathrm {2D} }+G_{\mathrm {2D} })}{\lambda _{\mathrm {2D} }+2G_{\mathrm {2D} ))))
4 K 2 D ( K 2 D − λ 2 D ) 2 K 2 D − λ 2 D {\displaystyle {\tfrac {4K_{\mathrm {2D} }(K_{\mathrm {2D} }-\lambda _{\mathrm {2D} })}{2K_{\mathrm {2D} }-\lambda _{\mathrm {2D} ))))
4 K 2 D G 2 D K 2 D + G 2 D {\displaystyle {\tfrac {4K_{\mathrm {2D} }G_{\mathrm {2D} )){K_{\mathrm {2D} }+G_{\mathrm {2D} ))))
λ 2 D ( 1 + ν 2 D ) ( 1 − ν 2 D ) ν 2 D {\displaystyle {\tfrac {\lambda _{\mathrm {2D} }(1+\nu _{\mathrm {2D} })(1-\nu _{\mathrm {2D} })}{\nu _{\mathrm {2D} ))))
2 G 2 D ( 1 + ν 2 D ) {\displaystyle 2G_{\mathrm {2D} }(1+\nu _{\mathrm {2D} })\,}
2 K 2 D ( 1 − ν 2 D ) {\displaystyle 2K_{\mathrm {2D} }(1-\nu _{\mathrm {2D} })}
4 G 2 D ( M 2 D − G 2 D ) M 2 D {\displaystyle {\tfrac {4G_{\mathrm {2D} }(M_{\mathrm {2D} }-G_{\mathrm {2D} })}{M_{\mathrm {2D} ))))
λ 2 D [ N / m ] = {\displaystyle \lambda _{\mathrm {2D} }\,[\mathrm {N/m} ]=}
2 G 2 D ( E 2 D − 2 G 2 D ) 4 G 2 D − E 2 D {\displaystyle {\tfrac {2G_{\mathrm {2D} }(E_{\mathrm {2D} }-2G_{\mathrm {2D} })}{4G_{\mathrm {2D} }-E_{\mathrm {2D} ))))
K 2 D − G 2 D {\displaystyle K_{\mathrm {2D} }-G_{\mathrm {2D} ))
2 G 2 D ν 2 D 1 − ν 2 D {\displaystyle {\tfrac {2G_{\mathrm {2D} }\nu _{\mathrm {2D} )){1-\nu _{\mathrm {2D} ))))
E 2 D ν 2 D ( 1 + ν 2 D ) ( 1 − ν 2 D ) {\displaystyle {\tfrac {E_{\mathrm {2D} }\nu _{\mathrm {2D} )){(1+\nu _{\mathrm {2D} })(1-\nu _{\mathrm {2D} })))}
2 K 2 D ν 2 D 1 + ν 2 D {\displaystyle {\tfrac {2K_{\mathrm {2D} }\nu _{\mathrm {2D} )){1+\nu _{\mathrm {2D} ))))
2 K 2 D ( 2 K 2 D − E 2 D ) 4 K 2 D − E 2 D {\displaystyle {\tfrac {2K_{\mathrm {2D} }(2K_{\mathrm {2D} }-E_{\mathrm {2D} })}{4K_{\mathrm {2D} }-E_{\mathrm {2D} ))))
M 2 D − 2 G 2 D {\displaystyle M_{\mathrm {2D} }-2G_{\mathrm {2D} ))
G 2 D [ N / m ] = {\displaystyle G_{\mathrm {2D} }\,[\mathrm {N/m} ]=}
K 2 D − λ 2 D {\displaystyle K_{\mathrm {2D} }-\lambda _{\mathrm {2D} ))
λ 2 D ( 1 − ν 2 D ) 2 ν 2 D {\displaystyle {\tfrac {\lambda _{\mathrm {2D} }(1-\nu _{\mathrm {2D} })}{2\nu _{\mathrm {2D} ))))
E 2 D 2 ( 1 + ν 2 D ) {\displaystyle {\tfrac {E_{\mathrm {2D} )){2(1+\nu _{\mathrm {2D} })))}
K 2 D ( 1 − ν 2 D ) 1 + ν 2 D {\displaystyle {\tfrac {K_{\mathrm {2D} }(1-\nu _{\mathrm {2D} })}{1+\nu _{\mathrm {2D} ))))
K 2 D E 2 D 4 K 2 D − E 2 D {\displaystyle {\tfrac {K_{\mathrm {2D} }E_{\mathrm {2D} )){4K_{\mathrm {2D} }-E_{\mathrm {2D} ))))
ν 2 D [ 1 ] = {\displaystyle \nu _{\mathrm {2D} }\,[1]=}
λ 2 D λ 2 D + 2 G 2 D {\displaystyle {\tfrac {\lambda _{\mathrm {2D} )){\lambda _{\mathrm {2D} }+2G_{\mathrm {2D} ))))
E 2 D 2 G 2 D − 1 {\displaystyle {\tfrac {E_{\mathrm {2D} )){2G_{\mathrm {2D} ))}-1}
λ 2 D 2 K 2 D − λ 2 D {\displaystyle {\tfrac {\lambda _{\mathrm {2D} )){2K_{\mathrm {2D} }-\lambda _{\mathrm {2D} ))))
K 2 D − G 2 D K 2 D + G 2 D {\displaystyle {\tfrac {K_{\mathrm {2D} }-G_{\mathrm {2D} )){K_{\mathrm {2D} }+G_{\mathrm {2D} ))))
2 K 2 D − E 2 D 2 K 2 D {\displaystyle {\tfrac {2K_{\mathrm {2D} }-E_{\mathrm {2D} )){2K_{\mathrm {2D} ))))
M 2 D − 2 G 2 D M 2 D {\displaystyle {\tfrac {M_{\mathrm {2D} }-2G_{\mathrm {2D} )){M_{\mathrm {2D} ))))
M 2 D [ N / m ] = {\displaystyle M_{\mathrm {2D} }\,[\mathrm {N/m} ]=}
λ 2 D + 2 G 2 D {\displaystyle \lambda _{\mathrm {2D} }+2G_{\mathrm {2D} ))
4 G 2 D 2 4 G 2 D − E 2 D {\displaystyle {\tfrac {4G_{\mathrm {2D} }^{2)){4G_{\mathrm {2D} }-E_{\mathrm {2D} ))))
2 K 2 D − λ 2 D {\displaystyle 2K_{\mathrm {2D} }-\lambda _{\mathrm {2D} ))
K 2 D + G 2 D {\displaystyle K_{\mathrm {2D} }+G_{\mathrm {2D} ))
λ 2 D ν 2 D {\displaystyle {\tfrac {\lambda _{\mathrm {2D} )){\nu _{\mathrm {2D} ))))
2 G 2 D 1 − ν 2 D {\displaystyle {\tfrac {2G_{\mathrm {2D} )){1-\nu _{\mathrm {2D} ))))
E 2 D ( 1 − ν 2 D ) ( 1 + ν 2 D ) {\displaystyle {\tfrac {E_{\mathrm {2D} )){(1-\nu _{\mathrm {2D} })(1+\nu _{\mathrm {2D} })))}
2 K 2 D 1 + ν 2 D {\displaystyle {\tfrac {2K_{\mathrm {2D} )){1+\nu _{\mathrm {2D} ))))
4 K 2 D 2 4 K 2 D − E 2 D {\displaystyle {\tfrac {4K_{\mathrm {2D} }^{2)){4K_{\mathrm {2D} }-E_{\mathrm {2D} ))))