Unformatted text preview: ition with body component thanks to two pairs: L1 and L2 for component 1 and L3 and L4 for component 2. Figure 5: Example Force exerted by this spring on point Pt1 depends on it stiffness noted S but also on actual distance l(1) between point Pt1 and point Pt2. A geometrical pair variation of position introduces a variation of distance between these points, hence a variation of force exerted by the spring, as shown figure 6. Figure 6: Rigid body movement influence We are able to find equation linking parameters of the geometrical pairs’ position and components’ point position: equation 5. Fx(1) = S.(Lini – l(1)) (5) Lini corresponds to the spring length when it is free of forces, and l(1) is actual distance between the two points. 306 G. Cid et al. l(1) = l nom (1) + d1 d2 d3 d4 .v M (1) + .v M (2) .v M (3) − .v M (4) d1 + d 2 d1 + d 2 d3 + d4 d3 + d4 In our example, v M ( 2) = 0 , v M (3) = 0 , v M ( 4) = 0 and l nom (1) has a numerical determined value. So we are able to write boundary conditions associated to this point: S .d 1 ⎧ ⎪ Fx(1) = (S.l ini -...
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- Spring '10
- The Land, ........., Computer-aided design, Joseph K. Davidson, M. GIORDANO