====== Contact materials ====== ===== Description ===== For all contact materials, a penalty along the normal direction and a depth at which contact is detected are required. Contact can be: * positively unilateral (''UNILATERAL_POSITIF''), contact for $\mbox{gap} \geq 0$ (by default) * negatively unilateral (''UNILATERAL_NEGATIF''), contact for $\mbox{gap} \leq 0$ * bilateral (''BILATERAL''), contact for both $\mbox{gap} \geq 0$ and $\mbox{gap}\leq 0$ __Choice of depth at which contact is detected:__ If the contact matrix is made of circles, the depth must be smaller than the smallest radius. If it is planar, the depth is arbitrary, but a large depth leads to a slow contact detection, when if the depth is too small some contacts can be missed. ===== FrictionlessContactMaterial ===== === Description === Contact without friction. === Parameters === ^ Name ^ Metafor Code ^ Dependency ^ Default ^ | Penalty along normal direction | ''PEN_NORMALE'' | ''TM'' | | | Depth at which contact is detected | ''PROF_CONT'' | - | | | Type of contact | ''TYPE_CONT'' | - | ''UNILATERAL_POSITIF'' | ===== FrictionlessVariablePenaltyContactMaterial ===== === Description === Contact without friction where penalty can depend on the gap. === Parameters === ^ Name ^ Metafor Code ^ Dependency ^ | Penalty along normal direction | ''PEN_NORMALE'' | ''GD'' | :!: No ''TM'' dependency here! An evolution function must be associated to ''PEN_NORMALE'' (depending on generalized displacements GD). ===== StickingContactMaterial ===== === Description === Sticking contact. A penalty along the tangential direction is added. === Parameters === ^ Name ^ Metafor Code ^ Dependency ^ | Penalty along normal direction | ''PEN_NORMALE'' | ''TM'' | | Penalty along tangential direction | ''PEN_TANGENT'' | ''TM'' | | Depth at which contact is detected | ''PROF_CONT'' | - | | Type of contact | ''TYPE_CONT'' | - | ===== StickingVariablePenaltyContactMaterial ===== === Description === Sticking contact where penalty can depend on the gap. === Parameters === ^ Name ^ Metafor Code ^ Dependency ^ | Penalty along normal direction | ''PEN_NORMALE'' | ''GD'' | | Penalty along tangential direction | ''PEN_TANGENT'' | ''GD'' | :!: No ''TM'' dependency here! An evolution function must be associated to ''PEN_NORMALE'' and/or ''PEN_TANGENT'' (depending on generalized displacements GD). These function can be different. ===== CoulombContactMaterial ===== === Description === Coulomb's friction law. A tangential penalty, a coefficient of static friction (setting the maximal tangential force before sliding) and a coefficient of dynamic friction (setting the value of the sliding force) are required. === Parameters === ^ Name ^ Metafor Code ^ Dependency ^ | Penalty along normal direction | ''PEN_NORMALE'' | ''TM'' | | Penalty along tangential direction | ''PEN_TANGENT'' | ''TM'' | | Depth at which contact is detected | ''PROF_CONT'' | - | | Coefficient of static friction | ''COEF_FROT_STA'' | ''TM'' | | Coefficient of dynamic friction | ''COEF_FROT_DYN'' | ''TM'' | | Type of contact | ''TYPE_CONT'' | - | ===== TrescaContactMaterial ===== === Description === Tresca's friction law. Friction do not depend on pressure. It is computed using penalty method with sticking contact, and starts sliding once the tangential stress reaches a threshold entered by the user. :!: This law requires the use of ''AREAINCONTACT'' = ''AIC_ONCEPERSTEP'' === Parameters === ^ Name ^ Metafor Code ^ Dependency ^ | Penalty along normal direction | ''PEN_NORMALE'' | ''TM'' | | Penalty along tangential direction | ''PEN_TANGENT'' | ''TM'' | | Depth at which contact is detected | ''PROF_CONT'' | - | | Static frictional shear factor | ''TRESCA_STA_M'' | ''TM'' | | Dynamic frictional shear factor | ''TRESCA_DYN_M'' | ''TM'' | | Initial shear yield stress | ''TRESCA_K'' | - | | Type of contact | ''TYPE_CONT'' | - | The threshold is usually computed using $m\,\sigma_0\,/\sqrt{3}$ where //m// is Tresca's coefficient of friction and $\sigma_0$ is the tensile yield stress of the material. ===== TmFrictionlessContactMaterial ===== Thermomechanical contact without friction. The heat flux $q_{N}$ normal to the contact interaction (going out of the slave surface) is given by $$q_{N} = h_c \left(p_{N} \right) \left(T^{S} - T^{M}\left(\bf{\xi}^{S}\right)\right), $$ where * $p_{N}$ is the contact pressure, * $T^{S}$ is the temperature of the slave node, * $T^{M}\left(\bf{\xi}^{S}\right)$ is the temperature of a point on the master surface corresponding to the closest projection of the slave node on the master surface, * $h_c$ is the thermal resistance under conduction. This thermal resistance under conduction $h_c$ is modeled as $$h_c \left(p_{N} \right) = h_{c0} \left(\frac{p_{N}}{H_v}\right)^{w}, $$ where * $H_v$ Vickers's material hardness , * $w$ is an exponent, * $h_{c0}$ is the nominal thermal resistance under conduction. === Parameters === ^ Name ^ Metafor Code ^ Dependency ^ | Penalty along normal direction | ''PEN_NORMALE'' | ''TM'' | | Depth at which contact is detected | ''PROF_CONT'' | - | | Nominal thermal resistance | ''CTM_H_NOMINAL'' | - | | Exponent | ''CTM_EXPONENT_E'' | - | | Material hardness | ''CTM_HARDNESS'' | - | | Type of contact | ''TYPE_CONT'' | - | :!: Not tested in 3D :!: ===== TmStickingContactMaterial ===== Sticking thermomechanical contact === Parameters === ^ Name ^ Metafor Code ^ Dependency ^ | Penalty along normal direction | ''PEN_NORMALE'' | ''TM'' | | Penalty along tangential direction | ''PEN_TANGENT'' | ''TM'' | | Depth at which contact is detected | ''PROF_CONT'' | - | | Nominal thermal resistance | ''CTM_H_NOMINAL'' | - | | Exponent | ''CTM_EXPONENT_E'' | - | | Material hardness | ''CTM_HARDNESS'' | - | | Type of contact | ''TYPE_CONT'' | - | :!: Not tested in 3D :!: ===== TmCoulombContactMaterial ===== === Description === Thermomechanical contact using Coulomb's friction law === Parameters === ^ Name ^ Metafor Code ^ Dependency ^ | Penalty along normal direction | ''PEN_NORMALE'' | ''TM'' | | Penalty along tangential direction | ''PEN_TANGENT'' | ''TM'' | | Depth at which contact is detected | ''PROF_CONT'' | - | | Coefficient of static friction | ''COEF_FROT_STA'' | ''TM'' | | Coefficient of dynamic friction | ''COEF_FROT_DYN'' | ''TM'' | | Nominal thermal resistance | ''CTM_H_NOMINAL'' | - | | Exponent | ''CTM_EXPONENT_E'' | - | | Material hardness | ''CTM_HARDNESS'' | - | | Type of contact | ''TYPE_CONT'' | - | :!: Not tested in 3D :!: ===== TmTrescaContactMaterial ===== === Description === Thermomechanical contact using Tresca's friction law === Parameters === ^ Name ^ Metafor Code ^ Dependency ^ | Penalty along normal direction | ''PEN_NORMALE'' | ''TM'' | | Penalty along tangential direction | ''PEN_TANGENT'' | ''TM'' | | Depth at which contact is detected | ''PROF_CONT'' | - | | Static frictional shear factor | ''TRESCA_STA_M'' | ''TM'' | | Dynamic frictional shear factor | ''TRESCA_DYN_M'' | ''TM'' | | Initial shear yield stress | ''TRESCA_K'' | - | | Nominal thermal resistance | ''CTM_H_NOMINAL'' | - | | Exponent | ''CTM_EXPONENT_E'' | - | | Material hardness | ''CTM_HARDNESS'' | - | | Type of contact | ''TYPE_CONT'' | - | The threshold is usually computed using $m\,\sigma_0\,/\sqrt{3}$ where //m// is Tresca's coefficient of friction and $\sigma_0$ is the tensile yield stress of the material. :!: Not tested in 3D :!: