【作者】 万琪；

【导师】 张炳炎； 王福花；

【作者基本信息】 中国舰船研究院 ， 船舶与海洋结构物设计制造， 2011， 硕士

【摘要】 三体船具有高航速、高耐波性、总体性能好、生存能力强等优点,但其航速高,承受砰击载荷较大,且必须严格控制重量。为了在减轻重量的同时满足强度要求,主船体往往采用铝合金或高强度钢减小构件尺寸,因此三体船的强度储备不太大,高海况或高航速航行时,结构响应呈现出高度非线性,结构较常规船更易屈曲。所以需要合理评估总纵极限强度。论文的主要内容有:(1)梳理了船体板、加筋板单元的纵向受压屈曲失效模式,采用解析法、规范法和非线性有限元法对各失效模式下的加筋板单元极限强度进行了计算和对比分析,验证了非线性有限元法ABAQUS的合理性,从而为板架和船体梁的极限强度计算作准备。(2)本文指出船体大跨度甲板板架通常存在纵骨多跨失稳的现象,而SMITH方法仅考虑纵向结构在横向框架间的屈曲失效,有一定局限性,并分析了多跨失稳板架的应力-应变曲线,通过与横向框架间加筋板单元应力-应变曲线作对比分析,对SMITH方法的适用性作了探讨。同时研究提出了多跨失稳的大跨度甲板板架稳定性计算方法和优化设计方法,最后对三体船机舱区甲板板架的极限强度进行了计算和评估。(3)分别用SMITH渐进崩溃法、舱段非线性有限元法和全船非线性有限元法对三体船的船体梁极限强度作对比分析,并与试验结果作对比分析,对三体船总纵弯曲极限强度进行了评估,对三体船船体梁极限强度的特征以及片体产生的影响进行分析,从而为三体船的设计提供技术支撑。论文取得的主要创新成果如下:(1)对船体加筋板单元、板架结构和船体梁结构的极限强度计算方法进行了全面的探讨和对比分析。(2)研究提出了大跨度甲板板架的稳定性计算方法和优化方法,针对SMITH方法的局限性,研究纵骨多跨失稳时的应力-应变曲线,应用于三体船板架结构的设计和极限强度评估。(3)提出采用舱壁多点加载的全船有限元分析直接评估三体船的极限强度,使得外载荷分布和船体结构实际承载能力在同一模型中得到模拟,直接得到实船的极限强度薄弱部位和承载能力,从而克服了SMITH法和舱段有限元法将载荷和结构承载能力分两步计算再进行评估的局限性。(4)在国内首次对高性能三体船型的船体结构进行了总纵弯曲极限强度评估,得出三体船片体对船体梁极限强度的影响,指出三体船极限强度与常规船体相比的特殊性,为三体船的设计提供技术支撑。更多还原

【Abstract】 The trimaran have following features: high speed, high sea keeping ability, good overall performance, and strong vitality. But as they are running at high speed, the endured slamming load is big, and the weight must be strictly limited .In order to reduce the weight while meet the strength requirement, main structures are usually made of aluminum alloy or high-strength steel to decrease the scantling of the structural member. So the trimaran have low strength margin, when sailing at heavy sea condition or high speed, the structure response appears highly nonlinear, and easier to get structural buckling than normal vessel. In this case,it is essential to evaluate the longitudinal ultimate strength .The main contents of this thesis are:(1) Summarize failure mode at longitude compressed buckling of plants and stiffened plant element. Using the analytic calculation、formulas of classification societies rules、and NFEM method to calculate and compare the ultimate strength of the stiffened plate elements in all failure modes. Verify the non-linear FEM method of ABAQUS, and make preparation for calculating the ultimate strength of grillage structure and hull girder.(2)Point out the phenomena of longitudinal multi-span buckling existed in long span hull deck , while SMITH method has its own limitations as it only considers the longi-structure buckling between ring frames. Analyse stress-strain curve of multi-span buckling plated grillage, compare it with stiffened plant element between ring frames. Discuss the applicability of SMITH method, issue the stability calculation method of long-span plated grillage in the condition of multi-span buckling, and suggest the optimize design. At last calculate and estimate the ultimate strength of trimaran main deck in engine room area.(3)Analyse ultimate strength of trimaran with SMITH method, compartment NFEM ,hull NFEM, then compare with the test result. Estimate the ultimate strength of trimaran under longitudinal bending, analyse the characteristic of ultimate strength of trimaran and the effect of the side hull. Finally provide the technical support of trimaran design.The thesis has following creative points:(1)It has analyzed and compared the calculation methods for ultimate strength of stiffened plate element , grillage structure and hull structure in all aspects.(2)Point out stability calculation method of long-span plated grillage and suggest the optimize design. Study the stress-strain curve under multi-span buckling of longitudinal regarding limitations of SMITH method, and apply it into trimaran grillage structure design and estimation of ultimate strength.(3)Use the hull NFEM under multi-bulkhead load to estimate the trimaran ultimate strength. It realize the external load distribution and actual carrying capacity simulate in the same model.Then direct gains the weakness point and ultimate strength.This method overcomes the limitation of SMITH method and compartment NFEM,those methods would divide the load and ultimate strength into two steps and make the calculation and estimation separately.(4)For the first time in China estimate the ultimate strength of trimaran under longitudinal bending, get the effect of side hull towards ultimate strength of hull girder, point out the speciality of trimaran ultimate strength comparing with common vessel, provide the technical support of trimaran design.更多还原