Author(s): M. P. Maattanen
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Keywords: No Keywords
Abstract: Ice loads at different locations in a wide structure or in different legs in a multilegged structure develop independently. A numerical model should be able to predict such synchronization and lock-in phenomena as observed in full scale. An earlier numerical integration program for calculating ice-induced selfexcited vibration response is extended to accept 3-dirnensional geometry and multi-point ice loading. Numerical integration is used for limit cycle response analysis. The results indicate that the developed model is capable to predict both saw tooth like ice force histories, as well as synchronized resonant type frequency lock-in to the lowest natural modes of the structure, depending on ice velocities. The change of ice thickness or velocity may change the lock-in to a different mode. Multilegged or wide structures with independent zones exhibit more likely lock-in vibrations with symmetric than asymmetric natural modes. At too low or high ice velocity, no lock-in with natural modes will take place.
Year: 1998