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按照材料力学方法和有限元方法计算小尺寸混凝土筒体的刚度,验证材料力学计算筒体拉压刚度、抗弯刚度和抗剪刚度的准确性;对于抗扭刚度,根据大量模型的计算结果采用神经网络得到经验公式,给出筒体刚度的简化计算方法。 相似文献
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为了提高浮式起重机篱笆式卷筒结构设计的安全性和可靠性,分析了包括筒体压力、端板压力和棘爪力在内的多层钢丝绳缠绕作用下卷筒体的受力情况,利用有限元技术计算了筒体-端板的结构强度和变形。同时给出了目前常用的稳定性计算方法,根据有限元法得到了卷筒在承受径向外压力、横向力作用下的整体稳定性,并对各种计算方法进行了比较。研究工作为结构优化设计提供了分析手段和参考依据。 相似文献
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为了研究不同外形和安装位置的压浪板对高速三体船阻力的影响,选取了展长B、弦长L、安装角度θ、主体安装高度H及侧体安装高度h等5个代表性参数,通过正交试验设计出16种参数组合,采用基于雷诺时均方法的SST k-ω湍流模型对加装不同压浪板的三体船静水航行过程进行数值模拟并验证模拟的准确性,极差分析得出5个参数对总阻力系数的影响顺序为H>h>B>L>θ。对较优参数组合压浪板进行多航速模拟,并监测静水阻力、纵倾、艉下沉、自由液面及船底压力等数据,分析压浪板减阻和改变航行姿态的原因,发现减阻效果随着航速的增大而逐渐明显,傅汝德数Fr为0.598时减阻率可达12.69%。 相似文献
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船舶在波浪中航行时的纵向运动性能是衡量船舶综合航行性能的重要指标.为了改善船舶在波浪中的纵向运动性能,本文基于首部减摇组合附体技术对某型船首部构型进行改造并通过水池模型试验对其静水阻力和耐波性进行了分析研究.在分析该船作业及航区特点的基础上,通过船首部线型改造及减纵摇组合附体构型优化,给出适用于该船的首部构型方案.应用CFD软件和修正切片法进行水动力性能分析,并对船首构型方案进行优选.将优选出的性能较优复合船型方案和原船型开展水池模型静水阻力与耐波性对比试验分析,验证减摇复合船型的静水阻力性能与耐波性能.试验结果表明,改造后的复合船型减纵摇效果明显,对应实船四级海况18节航速下纵摇与首部加速度有义值较原船型降低15%以上;复合船型静水阻力有所增加,实船18节航速下静水阻力增加13.5%. 相似文献
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穿浪多体船运动性能研究 总被引:9,自引:1,他引:8
在穿浪双体船基础上,加装半潜体或带被动式减纵摇鳍的半潜体使其成为消波穿浪多体船,航行性能大大提高。半潜体不仅对耐波性能有利,对静水阻力和船体结构强度都有利。试验表明半潜体使经济航速阻力减小18-23%,设计航速阻力减小5-7%。耐波性综合指标比穿波双体船有提高,特别是纵摇明显减小。 相似文献
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In this paper, the dynamic implosion responses of ring-stiffened cylindrical tubes under external hydrostatic pressure are reported. The ring-stiffened cylinder models were fabricated from commercial seamless aluminium-alloy 6061-T6 tubes. Six external stiffened models were constructed: three models with three stiffeners, and the other three with five stiffeners. To quantify the effects of stiffening on the structural behaviour, implosion tests were also performed on another three unstiffened tube models. In this study, a total of nine tube models were tested until their failure. Implosion was initiated by increasing the hydrostatic pressure in the chamber until the tubes collapsed, and the effects of different types of pressurising media were investigated: (i) water only and (ii) water and nitrogen gas combined. The implosion pressure pulse near the collapsing tube was recorded during the event. The models with five stiffeners increased the implosion pressure pulse by approximately 3.5 times compared with the unstiffened model. 相似文献
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The effect of hydrostatic pressure on the vibration dispersion characteristics of fluid-shell coupled structures was studied.Both fluid-loaded cylindrical shells and fluid-filled cylindrical shells were considered.Numerical analysis was applied to solve the dispersion equations for shells filled with or loaded with fluid at various hydrostatic pressures.The results for external pressure showed that non-dimensional axial wave numbers are nearly independent when the pressure is below the critical level.The in... 相似文献
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《Marine Structures》2000,13(2):91-106
The formulation of the hydrostatic stiffness for linear rigid body hydrodynamics is well known. An explicit formulation for an analogous hydrostatic stiffness in linear hydroelasticity, which is applicable to both rigid body and flexible displacement, is not as well-known. Three such formulations have been proposed previously in the literature, none of which is quite correct; all produce an unsymmetric stiffness matrix. An explicit formulation for the complete hydrostatic stiffness for flexible floating structures at rest in calm water is derived based on a consistent linearization of the external hydrostatic pressure and the internal structural stresses. The symmetry of the present formulation for a floating structure is proven analytically, and the unsymmetry of the hydrostatic stiffness for individual finite elements is discussed. The formulation will be of most interest to those who wish to extend linear potential theory hydrodynamic codes for rigid body analysis to deformable bodies. Several issues that are significant for practical implementation are discussed and several examples are presented. 相似文献
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This paper investigates the fatigue behaviour of filament wound Toray T700/Epotech X4201 composite pipes with different lay-ups. The present work compares the fatigue behaviour of coupon specimens manufactured with two different fiber orientations under tension-tension and tension-compression cyclic actions. The test results show that the lay-up and stress ratio have significant effect on the failure mechanism and fatigue life of carbon fiber reinforced polymer (CFRP) composite coupons. This paper develops an empirical model, which integrates the effect of stress ratio in a fatigue damage parameter, to evaluate the fatigue life of the CFRP filament wound coupons. Combined with the numerically calculated stresses at the critical locations corresponding to the fatigue damage locations, the proposed empirical model developed from the coupon test database predicts successfully the fatigue life of full diameter CFRP pipes, using stresses computed at critical locations in the CFRP pipe. 相似文献
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