共查询到18条相似文献,搜索用时 203 毫秒
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标准化刻度器是自然伽马能谱测井仪的重要部件,是伽马能谱测井仪实现仪器溯源要求,完成归一化的关键。本文将介绍标准化刻度器的溯源情况,重点阐述刻度器开发实现过程和试验对比结果验证,结果表明刻度器各项性能指标均达到研制要求,成功完成项目开发。 相似文献
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主要介绍了CPLD技术及其优点,CPLD的应用开发系统MAX plusⅡ,以及VHDL硬件描述语言。同时以自然伽马能谱测井仪为例,介绍了CPLD技术在仪器中数字电路部分的应用。 相似文献
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张力腿平台拉索的疲劳损伤 总被引:1,自引:1,他引:0
目前在分析张力腿平台(TLP)疲劳损伤时,通常限定平台只发生小位移,未考虑不利工况下平台发生有限位移的情况.在分析模型中考虑有限大位移后,会引入多种非线性因素,也会使TLP的动力响应明显不同于小位移情况,因此研究TLP有限位移下非线性波浪载荷引起的疲劳损伤十分重要.首先求得随机海浪作用下TLP拉索应力的时间历程曲线,并采用雨流法对其进行计数得到疲劳载荷谱;然后依据Miner累积损伤模型,求得TLP拉索在不利工况下的疲劳损伤;最后对ISSCTLP平台拉索在某海况下进行了疲劳损伤短期计算,并说明TLP拉索疲劳可靠度的计算方法. 相似文献
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本文主要研究在非线性混合海况(即风浪和涌浪组合海况)下,以NREL 5MW_Baseline Monopile近海风机为研究对象,对其塔筒底部(基线)所受到的剪力和弯矩载荷的动力响应进行仿真。在近海风机的时域仿真中,选用了Ochi-Hubble六参数波浪谱,并编制了该谱的程序嵌入到FAST中进行编译。计算过程中,共进行了20次10 min的仿真分析。对于得到的短期载荷,给出了波高程,塔筒底部首尾向剪力和弯矩在线性与非线性不规则波作用下的时程曲线对比图。采用分块最大值法对每一次的短期载荷提取极值,并基于20次仿真所得的极值,给出了塔筒底部首尾向剪力与弯矩在线性与非线性不规则波作用下的超越概率曲线对比图。研究表明,在非线性混合海况下进行近海风机塔筒底部载荷的动力响应研究,计算结果对工程实际应用具有指导意义。 相似文献
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Espen H. Cramer
Peter Friis Hansen
《Marine Structures》1994,7(6):537-566This paper presents a procedure for evaluating the long term response distribution in ship structures. A specified travel route through given geographical areas during the lifetime of the ship is defined. The individual scatter diagrams, describing the relative occurrence of different sea states for the geographical areas, are weighted with respect to the relative time occupancy of the ship. A two-dimensional analytical distribution is fitted to the weighted scatter diagram over the lifetime.
Frequency response functions for all the sectorial forces are calculated for different ship speeds, heading angles and loading conditions, and fitted to a bi-cubic spline. The wave spectrum is defined by applying a gamma spectrum. The response spectrum is found using a linear frequency domain analysis. From the response spectrum, the peak distribution of the response in each short term period, conditioned on the loading condition, the ship speed and the wave heading direction is computed. The peak distribution over the lifetime is estimated by unconditioning with respect to sea states, maneuvering and loading condition. 相似文献
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风暴中船舶安全池破损问题 总被引:8,自引:0,他引:8
选用实际在航货船船型,运用理论和模型试验相结合的方法确定非线性横摇运动方程各系数,研究了随机波浪和随机风中船舶安全池的破损问题.引入定量分析方法,考虑扰动波谱(例如ITTC谱)对安全池破损的影响以及脉动风速谱的作用,进一步揭示了安全池破损的内在机理及影响因素.本文认为,计算安全池时应选择合适的扰动波谱,风速脉动特性的影响是不能忽略的. 相似文献
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Taek S. Jang S.H. Kwon Takeshi Kinoshita 《Journal of Marine Science and Technology》2005,10(4):181-187
A new mathematical formulation for the realization of nonlinear wave profiles and its nonlinear solution procedure, based
on the Banach fixed-point theorem, is proposed. To apply the formulation, a nonlinear equation for the Stokes wave in a finite
depth was derived, and some numerical solutions are given. A numerical study showed that the proposed iteration method, based
on linear progressive wave potential only, enabled us to realize the Stokes nonlinear wave profiles in a finite depth. The
nonlinear strategy of iteration has a very fast convergence rate, i.e., only about 6–10 iterations are required to obtain
a numerically converged solution. 相似文献
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Xi-zeng Zhao 《船舶与海洋工程学报》2010,9(4):363-371
A numerical approach was performed to predict the propagation and transformation of nonlinear water waves. A numerical wave flume was developed based on the non-periodic high-order spectral (HOS) method. The flume was applied to analyze the effect of wave steepness and wavelength on the propagation of nonlinear waves. The results show that for waves of low steepness, the wave profile and the wave energy spectrum are stable, and that the propagation can be predicted by the linear wave theory. For waves of moderate steepness and steep waves, the effects associated with the interactions between waves in a wave group become significant and a train of initially sinusoidal waves may drastically change its form within a short distance from its original position. 相似文献
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在考虑Von Karman非线性位移—应变关系下,基于Hamilton变分原理建立了船舶推进轴系纵横耦合非线性动力学方程。利用Galerkin方法,导出系统第一阶模态振动微分方程,采用多尺度法求解该方程。获得了叶频激励下横向主共振响应方程组,利用伪弧长延拓法数值求解了该方程组的平衡解并分析了其稳定性。探讨了支承刚度、激励载荷、螺旋桨质量、阻尼比以及细长比对轴系纵横耦合效应的影响。研究表明:细长比越小,激励载荷越大,阻尼比越小,系统纵横耦合效应越强;增加后艉轴承刚度可以抑制纵横耦合效应,增加前艉轴承以及推力轴承刚度则增强纵横耦合效应,而中间轴承对其没有明显影响;与线性模型相比,纵横耦合效应使轴系横向共振时的频率大于其线性固有频率,在某些激励频率处,幅频响应曲线上存在多解使幅值出现跳跃现象。分析结果对船舶推进轴系的设计有指导意义。 相似文献