研究计入弹性变形铰接塔平台在深水中的非线性动力响应。将铰接塔平台简化为顶部具有集中质量,底部具有扭转线性弹簧约束的均匀弹性梁,考虑波浪对平台的作用,应用莫里森(Morison)公式计算铰接塔平台瞬时位置所受水动力,建立了铰接塔平台横向运动的偏微分方程,采用伽辽金方法计算波浪作用下铰接塔平台非线性动力响应。计算了铰接塔平台的固有频率和模态,得到了铰接塔平台不同频率波浪激励下各阶模态的动力响应。计算结果表明,在波浪激励下系统二阶模态将发生2、3、4倍超谐共振运动,并且揭示了弹性铰接塔平台在波浪作用下振动的不对称性。
Considering elastic deformation of the articulated tower plafform(ATP) ,the nonlinear dynamic response of ATP under wave excitation in deep water is studied. ATP is simplified intoa uniform beam model with one concentrated mass on the top and a torsional spring at the bottom. Considering wave load, the hydrodynamic force is evaluated at the instantaneous position of ATP by Morison formula, and the partial differential equation of transversal motion is established. The wave-excited nonlinear dynamic response of ATP is calculated by Galerkin' s method. The natural vibration frequencies and modes of ATP were obtained, and the dynamic response of each mode of ATP was investigated under wave excitation with different frequencies. The results show that supper - harmonic resonance of orders 2,3,4 occurs with the second mode of ATP, and that the unsymmetry of motion of ATP is described under wave excitation.