Are there any examples of beam-to-beam contact simulating a telescoping cylinder?
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Yes, please see the attached ANSYS 10.0 SP1 input file, "telescoping.inp". It uses tubular BEAM188 elements along with CONTA176 and TARGE170 elements. The small offset between the lines of beam nodes was used to set the contact normal directions. CONTA178 elements were used to lock the concentric tubes to one another as the inner most tube was pulled out, bringing along with it the next tube, and then the next, etc. The model was also reduced to 2D by setting UZ=ROTY=0.0 and spinning about the centerline was removed, too (ROTX=0.0). Convergence for poorly constrained beam elements is an issue. The constraints used were taken primarily to stabilize these beam elements - not to simplify the contact, which in itself is pretty robust. However, please note that the contact surfaces do not change, as they are defined by the real constants. The true outer surface of the beams (defined by section properties) are not considered for contact. As alluded to above, the line-to-line contact feature was never meant to be a comprehensive substitute to brick or even shell modeling with contact. You would get more accurate results using solids (or shells) then by using this feature. However, for crude applications where detailed results are not needed, this feature is very useful. . |
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