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Download full text - ELSA - Europa

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Coupling at the Interfaces<br />

• Two approaches possible: primal or dual<br />

Continuity of kinematic<br />

quantities is satisfied a priori<br />

(same nodes)<br />

• We use a dual approach:<br />

Continuity of kinematic<br />

quantities is enforced by<br />

suitable conditions<br />

(different nodes)<br />

– More general also in view of non-conforming interfaces<br />

109<br />

Coupling at the Interfaces (2)<br />

Dual approach (Gravouil & Combescure, 2001)<br />

• Simplest case: 2 S/Ds,<br />

conforming interface,<br />

same ∆t<br />

• The coupled problem may<br />

be written as:<br />

ext int<br />

⎧ M1U<br />

F<br />

1<br />

= F1+<br />

R<br />

i<br />

Fi − Fi<br />

1<br />

⎪<br />

⇐ equilibrium<br />

⎨M 2U <br />

2<br />

= F2 + R2<br />

Ri<br />

interface reactions<br />

⎪<br />

⎩CU<br />

<br />

1 1+ CU<br />

2 2<br />

= 0 ⇐ continuity at interface (constraint)<br />

i =1, 2 (sub-domain index)<br />

110<br />

55

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