波激振动对超大型集装箱船疲劳强度的影响研究
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摘要
超大型集装箱船具有开口大、刚度低和航速快等特点,导致其波激振动现象突出,增加了疲劳破坏风险。论文以18, 000TEU箱船为研究对象,考虑对称与反对称模态的共同作用,采用有限元法进行干模态分析。基于三维线性频域水弹性理论,对其进行水弹性效应分析。然后采用谱分析法,通过直接计算求解热点应力响应,结合线性累积损伤法,求得疲劳损伤值和疲劳年限,并将其与刚体理论结果对比,分析波激振动对舱口角隅疲劳的影响。研究表明:当遭遇频率接近船体湿固有频率时,波激振动效应会引起船体载荷高频响应及应力高频响应,使得舱口角隅疲劳累计损伤度大幅增加,疲劳寿命普遍降低约30%～40%,部分节点甚至高达50%多。
Due to characteristics of ultra large container ships such as large opening, low stiffness and high speed,springing effect becomes more serious and risk of fatigue failure increases. A modal analysis is done for a18,000 TEU container ship by FE method with consideration of both symmetric modal and unsymmetrical modal. Based on 3 D linear hydro-elastic method in frequency domain, elastic effect of wave load is analyzed.Spectral analysis method and linear cumulative damage method are adapted to calculate fatigue damage and fatigue life, in which the stress response at the hot spot is gained through direct calculation. Fatigue on the hatch corner with and without consideration of springing effect is calculated and compared each other. It is found that when the encounter frequency meets wet natural frequency of the hull, springing will lead to high-frequency response of wave loads and structure stress, which may generally increase fatigue damage by about 30%～40%, and even up to more than 50% for some details.
Due to characteristics of ultra large container ships such as large opening, low stiffness and high speed,springing effect becomes more serious and risk of fatigue failure increases. A modal analysis is done for a18,000 TEU container ship by FE method with consideration of both symmetric modal and unsymmetrical modal. Based on 3 D linear hydro-elastic method in frequency domain, elastic effect of wave load is analyzed.Spectral analysis method and linear cumulative damage method are adapted to calculate fatigue damage and fatigue life, in which the stress response at the hot spot is gained through direct calculation. Fatigue on the hatch corner with and without consideration of springing effect is calculated and compared each other. It is found that when the encounter frequency meets wet natural frequency of the hull, springing will lead to high-frequency response of wave loads and structure stress, which may generally increase fatigue damage by about 30%～40%, and even up to more than 50% for some details.
引文
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[10]BV.Guidelines for fatigue assessment of steel ships and offshore units[S].2016.
[2]汪雪良,嘉骏,顾学康,等.超大型矿砂船波激振动及颤振研究[J].江苏科技大学学报:自然科学版,2010(02):120-124.
[3]汪雪良,顾学康,胡嘉骏,等.大型LNG船波激振动模型试验研究[J].中国造船,2012(04):1-12.
[4]DRUMMEN I,STORHAUG G,MOAN T.Experimental and numerical investigation of fatigue damage due to waveinduced vibrations in a containership in head seas[J].Journal of Marine Science and Technology,2008.
[5]赵南,纪肖,李辉.弹振对船舶疲劳强度的影响[J].大连海事大学学报,2012(01):21-24.
[6]孙宇.超大型船舶弹振效应分析及其对疲劳强度的影响[D].哈尔滨:哈尔滨工程大学,2013.
[7]张腾.超大型集装箱船波激振动研究[D].大连:大连理工大学,2016.
[8]DERBANNE Q,MALENICA?,TUITMAN J T,et al.Validation of the global hydroelastic model for springing&whipping of ships[C]//11th International Symposium on Practical Design of Ships and Other Floating Structures,Rio de Janeiro,RJ,Brazil,Sep.19-25,2010:331-340.
[9]冯国庆.船舶结构疲劳强度评估方法研究[D].哈尔滨:哈尔滨工程大学,2006.
[10]BV.Guidelines for fatigue assessment of steel ships and offshore units[S].2016.