共查询到19条相似文献，搜索用时 171 毫秒
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文章为了改进被动约束阻尼柱壳结构的减振特性,解决引入约束阻尼的合理分布问题,提出了一种基于多目标遗传算法的优化设计方法。建立了以振动模态的前两阶损耗因子和引入约束阻尼材料总质量比为优化目标,以约束层、阻尼层厚度和粘弹性材料剪切模量为设计变量的多目标函数。利用遗传算法对Pareto最优进行优化选择,避免了对目标函数值的直接计算。通过分析和比较优化前后结构的模态振动频率变化以及幅频响应,表明引入质量太多会影响柱壳结构固有特性,而优化后结构能够避免太多的质量引入,并且具有更好的减振效果。 相似文献
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针对重庆交通大学航运与船舶工程学院研究生振动结构模态分析课程学时短、内容多且抽象、学生学习积极性不高、到课率低等问题,结合教学实际,通过创新教学模式、制定理论与工程实际相结合的教学内容、实施实验教学与科研结合等措施,对该门课程教学模式进行改革和创新。通过教学实践,研究生对振动结构模态分析课程的学习兴趣显著提高,课程教学改革取得良好效果。 相似文献
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研究了新风换气机的动态特性,以改善新风设备工作时的振动噪声,对XHBX-D2TH型号的新风换气机进行了试验模态研究,得到了新风机结构的8阶模态固有频率、阻尼比和模态振型等参数,为进行有限元模态仿真分析,振动、噪声分析与结构优化创造了条件. 相似文献
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为了研究橡胶浮置板轨道对城市高架箱梁结构的减振特性,建立了高架橡胶浮置板轨道结构三雏有限元模型,分析了当减振器刚度和轨道板长度变化对高架桥系统动力响应影响。研究结果表明。减振器刚度的改变对浮置板前10阶振动频率分布影响较大,对累积质量分数分布特性几乎没有影响,相同阶数条件下浮置板的振动主频随减振器刚度减小而减小;列车通过时浮置板轨道以增大自身的振动来达到减小对桥梁结构振动能量输入的目的,在减振频率范围内,浮置板的减振效果随减振器刚度增大而减小,随浮置板长度的减小而减小。 相似文献
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康晶 《辽宁科技学院学报》1996,(4):29-32
文章利用平面波动理论对某煤气管道进行气往动力特性分析，计算气柱固有频率和共管长，从而进行管道振动分析；并提出减振设计方案降低气体压力脉动；将着段内气体压力驻波转变成行液，消除或减小管道振动激发因素，保证安全生产。进行 相似文献
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以某加工中心主轴部件-主轴箱体为例,应用有限元分析法分析了主轴箱体的模态特性参数,得到主轴箱体振动的前5阶固有频率和相应振型,采用比利时LMS设备对该模型进行测试验证.结果显示,理论模态参数与试验模态参数的相对误差小于7％,各阶振型一致. 相似文献
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为了获取某四驱汽车防滑差速器壳体的固有振动特性和验证所建有限元模型的正确性,以某四驱汽车防滑差速器壳体为研究对象,首先基于Abaqus软件对其进行模态仿真分析,得到了防滑差速器前6阶固有特性参数及其振型;然后运用锤击实验对防滑差速器进行模态分析实验,测取其振动情况;最后将两种方法获取的差速器壳体前6阶振型及振动频率进行对比。结果发现两种方法获取的各阶振型基本一致,固有频率误差在5%以内。这种以模态仿真分析为前提,模态实验为补充,仿真结果与实验结果相对比的分析方法有效地验证了有限元模型的正确性,为防滑差速器的有限元分析提供了有效的参考依据。 相似文献
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振动、噪声是开关型磁阻电动机调速系统较突出的问题和研究难点,为了深入了解SR电机定子凸极对其振动特性的影响,以有限元分析软件ANSYS为工具,建立研究SR电机定子凸极振动特性的2D、3D有限元分析模型,研究SR电机定子凸极对其固有频率和振动模态的影响。 相似文献
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船舶板架结构除了受到自身重力和设备重力作用外,还受到激振力的作用。应用大型有限元软件ANSYS软件对部分船体板架在受设备激振力和不受设备激振力两种情况进行计算,并就计算结果进行对比分析。结果显示,往往被我们忽视的激振力对船舶板架结构强度的影响不容忽视。 相似文献
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针对高校新能源、电气和自控专业学生普遍缺乏针对风力机叶片振动控制的实践环节,提出了基于LabVIEW的风力机叶片振动特性与控制仿真实验设计方案,该方案利用LabVIEW搭建了风力机叶片的经典颤振模型,建立叶片振动特性与控制仿真实验系统。整个仿真实验系统,可在多种典型风速场景下进行叶片振动特性实验,同时,可自行设计控制参数,进行叶片PID振动控制和自适应振动控制的仿真。通过直观的虚拟仿真交互系统,有效克服了场地和设备带来的时间、空间上的局限,促进学生对于风力机叶片振动特性的了解,增强了叶片振动控制设计的实践能力。 相似文献
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船体结构舾装开孔是船体专业与舾装专业协同设计的重要组成部分.为了加强协调能力、规范开孔流程、实现开孔数据的管理,通过分析鹰图船舶设计软件Smart 3D(S3D)的二次开发能力和船舶跨专业协同设计流程,结合邮轮设计和船厂设计实际生产业务的需求,利用S3 D二次开发框架,制定开孔协同处理规则,结合数据库设计,开发出统一的... 相似文献
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在营运过程中,船体本身具有一个固有频率。如果能准确知道它的固有频率,将对船舶设计有很大帮助。本文采用目前流行的有限元分析软件,计算分析某船体吊机舱的固有频率,分析结果对设备选型与布置安装有一定的指导意义。 相似文献
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船体外板复杂曲面自动化加工一直是船舶制造业研究热点和难点,由于加工过程中船板变形影响因素过多,导致船板加工变形预测一直不够准确快速。鉴于此,将两种复合变量用来表征加工过程中热源对应的众多加工参数,采用人工鱼群算法（AFSA）优化的支持向量机（SVM）预测船板变形。经实验验证,复合参数输入的AFSA-SVM模型预测船体外板水火线加热工艺变形线平均精确度为99.87%,角变形平均精确度为99.53%,且全局最优。将其与传统的PSO-SVM模型对比,不仅精确度有了提高,而且避免了局部极值导致的部分预测结果误差过大情况。 相似文献
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《浙江大学学报(A卷英文版)》2021,(1)
To improve the low-frequency vibration reduction effect of a steel spring floating slab track(FST), nonlinear quasizero-stiffness(QZS) vibration isolators composed of positive stiffness elements(PSEs) and negative stiffness elements(NSEs) were used to support the FST. First, considering the mechanical characteristics of the nonlinear QZS vibration isolators and the dynamic displacement limit(3 mm) of the FST, the feasible parameter groups were studied with the nonlinear stiffness variation range and bearing capacity as evaluation indices. A vertical vehicle quasi-zero-stiffness floating slab track(QZS-FST) coupled dynamic model was then established. To obtain a reasonable nonlinear stiffness within a few millimeters, the original length of the NSEs must be analyzed first, because it chiefly determines the stiffness nonlinearity level. The compression length of the NSEs at the equilibrium position must be determined to obtain the low stiffness of the floating slab without vehicle load. Meanwhile, to meet the dynamic displacement limit of the FST, the PSE stiffness must be increased to obtain a higher stiffness at the critical dynamic displacement. Various stiffness groups for the PSEs and NSEs can provide the same dynamic bearing capacity and yet have a significantly different vibration reduction effect. Excessive stiffness nonlinearity levels cannot effectively improve the vibration reduction effect at the natural frequency. Furthermore, they also significantly amplify the vibrations above the natural frequency. In this paper, the vertical vibration acceleration level(VAL) of the floating slab and the supporting force of the FST can be decreased by 6.9 dB and 55%, respectively, at the resonance frequency. 相似文献
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船舶建造行业是一个劳动密集型和技术密集型兼备的装备制造业,船体装配工在船舶建造领域扮演着重要的角色.船体装配工岗位核心能力的高低,决定着船舶与海洋工程主体结构的建造质量,所以船体装配工岗位核心能力的训练应当得到船舶建造企业和院校的重视.因此,对船体装配工岗位核心能力的训练方法及注意问题进行详细阐述,以期为船舶建造行业培养出更多高素质技能人才. 相似文献
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Low frequency vibrations induced by underground railways have attracted increasing attention in recent years. To obtain the
characteristics of low frequency vibrations and the low frequency performance of a floating slab track (FST), low frequency
vibration tests on an FST in an underground laboratory at Beijing Jiaotong University were carried out. The FST and an unbalanced
shaker SBZ30 for dynamic simulation were designed for use in low frequency vibration experiments. Vibration measurements were
performed on the bogie of the unbalanced shaker, the rail, the slab, the tunnel invert, the tunnel wall, the tunnel apex,
and on the ground surface at distances varying from 0 to 80 m from the track. Measurements were also made on several floors
of an adjacent building. Detailed results of low frequency vibration tests were reported. The attenuation of low frequency
vibrations with the distance from the track was presented, as well as the responses of different floors of the building. The
experimental results could be regarded as a reference for developing methods to control low frequency vibrations and for adopting
countermeasures. 相似文献
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In order to find a simple and programmed method to analyze the reliability of hull beams when fatigue and corrosion act on ships, the stress of ships is to be calculated in compliance with the longitudinal bending and cross-section modulus of ship beams. The calculation value of stress is to be compared with the allowable stress in order to gain the actual ship load and margin of safety, and then assess the reliability and failure probability of ship beams. The longitudinal bending moment is a random variable; the fatigue and cauterization are also random variables; and as the ship is influenced by cumulative damage of fatigue and cauterization, the cross-section modulus is a time-varying random variable. The reliability and failure probabilities can be actually reflected through the reliability analysis method. The analysis results indicate that in the service time of ships, as the age of ship increases and the fatigue and corrosion effects accumulate, the reliability of ship beams decreases and the failure probability increases, especially after 15 to 20 years. 相似文献