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| 2. |
Selection of the displacement models |
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It is generally not possible to select a displacement function that can represent exactly the actual variation of displacement in the element. Hence, the basic approximation of the finite element method is introduced at this stage. There are three interrelated factors, which influence the selection of a displacement model. |
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The type and degree of displacement model must be chosen. |
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The particular displacement magnitude that describes the model must be selected. These are usually the displacement at nodal points, but they may also include the derivation of the displacement at some or all of the nodal points. |
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The displacement model must specify certain requirements, which ensure that the numerical result approach the correct solution. |
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Fig.3.15 Displacements and forces acting at corresponding nodes |
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Displacement matrix,  Force Matrix,  |
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