Oasys LS-DYNA Environment 8.1 VOLUME 3 ... - Oasys Software

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Oasys LS-DYNA Environment: User Guide (Version 8.1) Type 6: *CONTACT_TIED_NODES_TO_SURFACE Type o6: *CONTACT_TIED_NODES_TO_SURFACE_OFFSET These are the same as types 2 and o2 except that the slave side is defined by individual nodes instead of segments. SHELL EDGE TIED TO SHELL SURFACE Type 7: *CONTACT_TIED_SHELL_EDGE_TO_SURFACE Type o7: *CONTACT_TIED_SHELL_EDGE_TO_SURFACE_OFFSET These are the same as types 6 and o6 except that rotational degrees of freedom are also tied together, allowing moments to be transferred. NODES SPOTWELDED TO SURFACE Type 8: *CONTACT_TIEBREAK_NODES_TO_SURFACE Slave nodes are tied to the masters until a failure criterion is reached. Thereafter they can slide on or separate from the masters as in a type 5 contact surface. This type of surface can be used to represent spot-welded or bolted connections. Before failure, pinning is achieved using penalty stiffness, not kinematic constraint, so the warnings applying to tied interfaces do not apply to type 8. TIEBREAK Type 9: *CONTACT_TIEBREAK_SURFACE_TO_SURFACE This is similar to type 8 except that failure is based on stress rather than force at individual nodes. It can be used to model fracture or rupture of a component where the failure plane is known in advance, for example bolts in the lid of a transport container. ONE WAY SLIDING WITH VOIDS Type 10: *CONTACT_ONE_WAY_SURFACE_TO_SURFACE Type a10: *CONTACT_AUTOMATIC_ONE_WAY_SURFACE_TO_SURFACE Type m10: *CONTACT_FORMING_ONE_WAY_SURFACE_TO_SURFACE These are identical to types 5, a5 and m5 except that the slave surface is defined using segments (or parts) instead of nodes. Page 9.4
Oasys LS-DYNA Environment: User Guide (Version 8.1) ERODING CONTACT Type 14: *CONTACT_ERODING_SURFACE_TO_SURFACE Type 15: *CONTACT_ERODING_SINGLE_SURFACE Type 16: *CONTACT_ERODING_NODES_TO_SURFACE These are used instead of types 3, 13 and 5 respectively where solid elements may fail. The purpose of these is to allow contact to occur with the remaining elements, after the elements originally forming the surface have failed. CONSTRAINT CONTACT Type 17: *CONTACT_CONSTRAINT_SURFACE_TO_SURFACE Type 18: *CONTACT_CONSTRAINT_NODES_TO_SURFACE Types 17 and 18 are similar to types 3 and 5, respectively, except that the penetrating slaves and masters are constrained to move together, using conservation of momentum to determine the combined velocity. This method eliminates contact penetrations and is useful for high pressure or high-speed impacts where penalty methods would generate unacceptably high penetrations. However, they cannot be used with nodes that are constrained in other ways, and are prone to instability problems if artificial penetrations occur (see later). NONLINEAR CONTACTS Type 19: *CONTACT_TWO_WAY_RIGID_BODY_TO_RIGID_BODY Type 20: *CONTACT_RIGID_NODES_TO_RIGID_BODY Type 21: *CONTACT_RIGID_BODY_ONE_WAY_TO_RIGID_BODY Contact types 19, 20 and 21 are similar to types 3, 5 and 10 respectively, except that instead of a linear stiffness to resist penetration, the user defines a force-deflection curve. They are intended to allow inclusion of energy-absorbing compliance without the need for modelling deformable elements. More details are given under "Contact Surface Stiffness" - see below. GEOMETRIC CONTACTS It is possible to model contact between an arbitrary surface and a rigid body where the shape of the rigid body is defined geometrically. Possible shapes are flat planes, spheres, cylinders and ellipsoids. The main purpose of geometric contacts is to permit LS-DYNA to be coupled with other programs that define objects geometrically, (e.g. MADYMO), since it removes the need for the analyst to mesh the objects. It is recommended that these contact types are not used in normal (uncoupled) analyses as they are slow and can produce stability problems where rigid/rigid contact is modelled. Page 9.5
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Oasys LS-DYNA Environment 8.1 VOLUME 3 ... - Oasys Software

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