Dual-Domain Structural Analysis

The constraints used depend on the type of element chosen. As an example, consider the triangular facet shell element mentioned above. The element has six degrees of freedom (DOF) at each node, including three displacement DOF (wi, U2, m3 and three rotational DOF (0j, 62, 63), defined in the local element system. The drilling rotational DOF about a local reference surface normal is used in the membrane formulation, and is given by 

Assume that a node n at the bottom element matches the node p at the top element as shown in Fig. 8.12a. A node is said to match a point on the opposite surface, if their connection line is parallel to the normal of the midsurface. We require that the normal to the midsurface before deformation should remain straight after deformation. Then there is a relationship between the degrees of freedom of node n and point p, which can be written as 

This system of constraints is imposed at all nodes on the bottom (or top) surface of the model. With these constraints, the structural performance of the composite structure is identical to the original plate. 

Fan et al. (2004a) described a hybrid element scheme for the 3D warpage analysis. The idea is to use 4-node first order tetrahedral elements only in chunky areas, but use 10-node second-order tetrahedral elements in the thin-walled areas and 5-9 node tetrahedral elements in the transitional areas. 

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Fig. 8.12 The matching points in dual domain structural analysis, a Node n at the bottom element matches a node at the top element, b Node n at the bottom element matches a point within the top element...

On the basis of a dual function of UGA as a codon for selenocysteine insertion and for translation termination within a single cell, it has to be assured (1) that this UGA codon is not used as a termination signal and (2) that selenocysteyl-tRNA is directed only to this position. The results of a biochemical analysis indeed revealed that this is achieved by the formation of a complex between SelB, selenocysteyl-tRNA, and the stem-loop structure downstream of the UGA. The binding to the SECIS element was shown to involve an ultimate 17-kDa C-terminal domain of SelB. 

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