不规则条带装箱问题是切分与布局问题的子问题,且在工业制造领域中尤为常见.该文针对2维不规则单箱装箱问题(two-dimensional irregular single bin size bin packing problem)中的特殊变种条带装箱问题,提出结合闵可夫斯基和(即闵可夫...不规则条带装箱问题是切分与布局问题的子问题,且在工业制造领域中尤为常见.该文针对2维不规则单箱装箱问题(two-dimensional irregular single bin size bin packing problem)中的特殊变种条带装箱问题,提出结合闵可夫斯基和(即闵可夫斯基加法)与遗传算法的综合求解的算法,其中遗传算法在优化算法中起到整体框架的作用,并在通过闵可夫斯基和寻找到候选放置位置后使用启发式的方法进行放置,同时讨论了在特定情况下该算法与传统优化方法的对比效果.在实际数据测试(50块数据集)中,较成熟的商业软件SVGnest得到的最终面积利用率为78.94%,应用该文的启发式算法,最终面积实用率提升到81.2%.展开更多
The purpose of this study is to investigate the suppression effect of a nonlinear energy sink(NES)on the wind-vortex-induced pipe vibration and explore the influence of damping,stiffness,and NES installation position ...The purpose of this study is to investigate the suppression effect of a nonlinear energy sink(NES)on the wind-vortex-induced pipe vibration and explore the influence of damping,stiffness,and NES installation position on the suppression effect.In this work,the wind-vortex-induced vibration of an elastic pipe of a deepwater jacket was studied,and vibrations were suppressed by using an NES.A van der Pol wake oscillator was used to simulate vortex-induced force,and the dynamic equation of the pipe considering the NES was established.The Galerkin method was applied to discretize the motion equation,and the vortex-induced vibration(VIV)of the pipe at reduced wind speeds was numerically analyzed.The novelty of this research is that particle swarm optimization was used to optimize the parameters of the NES to improve vibration suppression.The influence of the installation position,nonlinear stiffness,and damping parameters of the NES on vibration suppression was analyzed.Results showed that the optimized parameter combinations of the NES can effectively reduce wind-vortex-induced pipe vibration.The installation position of the NES had a significant effect on vibration suppression,and the midpoint of the pipe was the optimal NES installation position.An increase in stiffness or a 10% decrease in damping may cause vibration suppression failure.The results of this study provide some guidance for VIV suppression in deepwater jacket pipes.展开更多
研究了大型导管架平台卧式建造时出现单边约束圆管的风致涡激振动问题。将建造过程中单边约束的导管架圆管简化成悬臂梁模型,采用van der Pol尾流振子模型模拟圆管受到的流体力,建立了圆管风致涡激振动动力学方程。使用伽辽金方法对建...研究了大型导管架平台卧式建造时出现单边约束圆管的风致涡激振动问题。将建造过程中单边约束的导管架圆管简化成悬臂梁模型,采用van der Pol尾流振子模型模拟圆管受到的流体力,建立了圆管风致涡激振动动力学方程。使用伽辽金方法对建立的运动方程进行求解,数值分析了圆管在特定约化风速下的涡激振动特性。在圆管上附加非线性能量阱(NES)作为被动减振装置对圆管进行减振,并采用粒子群优化算法对NES的非线性刚度和阻尼参数进行了优化。结果表明,在约化速度为4.8时,得到的NES优化的非线性刚度和阻尼参数组合可以有效减小悬臂梁自由端风致涡激振动位移。本研究说明采用NES和粒子群优化算法可以有效减小圆管的风致涡激振动,为导管架安全建造提供一定的参考。展开更多
文摘不规则条带装箱问题是切分与布局问题的子问题,且在工业制造领域中尤为常见.该文针对2维不规则单箱装箱问题(two-dimensional irregular single bin size bin packing problem)中的特殊变种条带装箱问题,提出结合闵可夫斯基和(即闵可夫斯基加法)与遗传算法的综合求解的算法,其中遗传算法在优化算法中起到整体框架的作用,并在通过闵可夫斯基和寻找到候选放置位置后使用启发式的方法进行放置,同时讨论了在特定情况下该算法与传统优化方法的对比效果.在实际数据测试(50块数据集)中,较成熟的商业软件SVGnest得到的最终面积利用率为78.94%,应用该文的启发式算法,最终面积实用率提升到81.2%.
基金supported by the Tianjin Municipal Transportation Commission Project(No.2018-b2).
文摘The purpose of this study is to investigate the suppression effect of a nonlinear energy sink(NES)on the wind-vortex-induced pipe vibration and explore the influence of damping,stiffness,and NES installation position on the suppression effect.In this work,the wind-vortex-induced vibration of an elastic pipe of a deepwater jacket was studied,and vibrations were suppressed by using an NES.A van der Pol wake oscillator was used to simulate vortex-induced force,and the dynamic equation of the pipe considering the NES was established.The Galerkin method was applied to discretize the motion equation,and the vortex-induced vibration(VIV)of the pipe at reduced wind speeds was numerically analyzed.The novelty of this research is that particle swarm optimization was used to optimize the parameters of the NES to improve vibration suppression.The influence of the installation position,nonlinear stiffness,and damping parameters of the NES on vibration suppression was analyzed.Results showed that the optimized parameter combinations of the NES can effectively reduce wind-vortex-induced pipe vibration.The installation position of the NES had a significant effect on vibration suppression,and the midpoint of the pipe was the optimal NES installation position.An increase in stiffness or a 10% decrease in damping may cause vibration suppression failure.The results of this study provide some guidance for VIV suppression in deepwater jacket pipes.
文摘研究了大型导管架平台卧式建造时出现单边约束圆管的风致涡激振动问题。将建造过程中单边约束的导管架圆管简化成悬臂梁模型,采用van der Pol尾流振子模型模拟圆管受到的流体力,建立了圆管风致涡激振动动力学方程。使用伽辽金方法对建立的运动方程进行求解,数值分析了圆管在特定约化风速下的涡激振动特性。在圆管上附加非线性能量阱(NES)作为被动减振装置对圆管进行减振,并采用粒子群优化算法对NES的非线性刚度和阻尼参数进行了优化。结果表明,在约化速度为4.8时,得到的NES优化的非线性刚度和阻尼参数组合可以有效减小悬臂梁自由端风致涡激振动位移。本研究说明采用NES和粒子群优化算法可以有效减小圆管的风致涡激振动,为导管架安全建造提供一定的参考。