doc:user:elements:contact:rigid_matrices
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doc:user:elements:contact:rigid_matrices [2013/07/10 17:03] – [Définition des matrices rigides] joris | doc:user:elements:contact:rigid_matrices [2016/03/30 15:23] (current) – external edit 127.0.0.1 | ||
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+ | ====== Rigid matrices ====== | ||
+ | ===== Defining rigid matrices ===== | ||
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+ | In Metafor, any geometric entity can be defined as rigid [[doc: | ||
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+ | However, the orientation of the entity is relevant. It defines the area considered as the die, where a penetrating node will experience a contact force. By convention, the normal vector is pointing inside the die. | ||
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+ | < | ||
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+ | This normal $\boldsymbol{n}$ is defined as stated below. | ||
+ | * **In 2D:** The convention states that the cross product $\boldsymbol{t} \wedge \boldsymbol{n} = (0,0,1)$. This is equivalent in saying that the contact matrix is defined with its //**area to the left**// (when following the line defining the matrix, any node trying to penetrate in the aerea to the left will experience a contact force). | ||
+ | * The orientation of a '' | ||
+ | * The orientation of a'' | ||
+ | * **In 3D:** The normal of a '' | ||
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+ | For rigid-defo contact, when '' | ||
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+ | It is also possible to reverse the convention defining where the surface matrix is, changing the value of '' | ||
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+ | ===== Contact - motion of matrices ===== | ||
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+ | In Metafor, moving contact matrices is done by moving geometric entities in the contact interaction with a '' | ||
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