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Shape Anisotropy and Resonance Mode Guided Reliable Interconnect Design for In-plane Magnetic Logic
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作者 Xiao-Kuo Yang Bin Zhang +4 位作者 Jia-Hao Liu Ming-Liang Zhang Wei-Wei Li Huan-Qing Cui Bo Wei 《Chinese Physics Letters》 SCIE CAS CSCD 2018年第5期129-132,共4页
Dipole coupled nanomagnets controlled by the static Zeeman field can form various magnetic logic interconnects.However, the corner wire interconnect is often unreliable and error-prone at room temperature. In this stu... Dipole coupled nanomagnets controlled by the static Zeeman field can form various magnetic logic interconnects.However, the corner wire interconnect is often unreliable and error-prone at room temperature. In this study, we address this problem by making it into a reliable type with trapezoid-shaped nanomagnets, the shape anisotropy of which helps to offer the robustness. The building method of the proposed corner wire interconnect is discussed,and both its static and dynamic magnetization properties are investigated. Static micromagnetic simulation demonstrates that it can work correctly and reliably. Dynamic response results are reached by imposing an ac microwave field on the proposed corner wire. It is found that strong ferromagnetic resonance absorption appears at a low frequency. With the help of a very small ac field with the peak resonance frequency, the required static Zeeman field to switch the corner wire is significantly decreased by ~21 m T. This novel interconnect would pave the way for the realization of reliable and low power nanomagnetic logic circuits. 展开更多
关键词 net In shape Anisotropy and Resonance Mode Guided Reliable Interconnect Design for in-plane Magnetic Logic
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Modal macro-strain identification from operational macro-strain shape under changing loading conditions 被引量:1
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作者 李舒 徐赵东 +1 位作者 王少杰 吴智深 《Journal of Southeast University(English Edition)》 EI CAS 2016年第2期219-225,共7页
To develop modal macro-strain ( MMS ) identification techniques and improve their applicability in a continuous health monitoring system for civil infrastructures, the concept of operational macro-strain shape (OMS... To develop modal macro-strain ( MMS ) identification techniques and improve their applicability in a continuous health monitoring system for civil infrastructures, the concept of operational macro-strain shape (OMSS) and the corresponding identification method are proposed under unknown ever-changing loading conditions, and the MMS is then obtained. The core of the proposed technique is mainly based on the specific property that the macro-strain transmissibility tends to be independent of external excitations at the poles of the system and converges to a unique value. The proposed method is verified using the experimental data from a three-span continuous beam excited by an impact hammer at different locations. The identified results are also compared with the commonly used methods, such as the peak- picking (PP) method, the stochastic subspace identification (SSI) method, and numerical results, in the case of unknown input forces. Results show that the proposed technique has unique merits in accuracy and robustness due to its combining multiple tests under changing loading conditions, which also reveal the promising application of the distributed strain sensing system in identifying MMS of operational structures, as well as in the structural health monitoring (SHM) field. 展开更多
关键词 macro-stain/distributed strain fiber Bragggrating FBG operational modal analysis OMA operational deflection shape (ODS) TRANSMISSIBILITY
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核电工程异形水箱流固耦合分布式参数模型与效用研究
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作者 李建波 刘佳 +1 位作者 李志远 林皋 《振动与冲击》 EI CSCD 北大核心 2024年第8期43-51,77,共10页
在流固耦合动力分析领域,传统的Housner模型在工程设计中发挥重要作用。但其理论推导仅适用于规则水箱,采用集中质量总体模型描述液体晃动的整体效应,难以有效模拟异形水箱储液结构的局部精细响应,亟须建立适用于不规则水体晃荡的分布... 在流固耦合动力分析领域,传统的Housner模型在工程设计中发挥重要作用。但其理论推导仅适用于规则水箱,采用集中质量总体模型描述液体晃动的整体效应,难以有效模拟异形水箱储液结构的局部精细响应,亟须建立适用于不规则水体晃荡的分布式附加质量模型。基于势流理论推导了一种模态综合法模型,实现了分布质量与储液器壁激振加速度的解耦。该模型能够有效剥离分布式的脉冲质量与对流质量;同时,实体网格的振型分析适用于任意形状水体的动力分析。通过算例的形式将该模型与精细声学-结构耦合(Acoustic-Structural coupling,CAS)模拟法进行了比较,验证了模型的精确性与可靠性。最后,基于本文的模型研究了核电异形的安全水箱在不同水位和减晃格栅分布下的动力响应规律,并检验了其在工程中的适用性。 展开更多
关键词 流固耦合 动水分布式质量模型 模态综合法 核电异形水箱
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深水钻井隔水管横向振动振型分析
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作者 韩春杰 姜继帅 +2 位作者 袁建 马文倩 荆国林 《化工自动化及仪表》 CAS 2024年第3期456-461,515,共7页
为了分析深水钻井隔水管的横向振动固有频率和振型,综合考虑深水隔水管受到的顶部张紧力、海洋环境载荷、钻井平台漂移等作用力,借助微元法建立受力分析模型。根据连续梁理论和隔水管单元的动力学微分方程,确定其无阻尼自然振动基本方程... 为了分析深水钻井隔水管的横向振动固有频率和振型,综合考虑深水隔水管受到的顶部张紧力、海洋环境载荷、钻井平台漂移等作用力,借助微元法建立受力分析模型。根据连续梁理论和隔水管单元的动力学微分方程,确定其无阻尼自然振动基本方程,并进一步剖析建立隔水管横向振动固有频率微分方程和模态振型基本方程,然后进行数值求解。使用控制变量法逐步分析隔水管长度、张力比、自身材质对隔水管固有频率的影响和变化规律。通过MATLAB软件表现出不同阶数的振动振型,结果表明:控制张力比、合理选择隔水管类型能够有效提高固有频率,避免与波流力形成共振,进而保证深水钻井作业安全。此外,隔水管的振型并不是标准正弦曲线,振型会受时间的影响不断变化。 展开更多
关键词 模态振型 深水钻井隔水管 力学分析 固有频率 控制变量法 MATLAB
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基于跨模型模态应变能变化的结构损伤识别两阶段法
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作者 朱学坤 李翠 +2 位作者 俞记生 张雅儒 伍晓顺 《力学季刊》 CAS CSCD 北大核心 2024年第1期210-221,共12页
为提高结构损伤识别精度,采用跨模型模态应变能变化(Cross-model Modal Strain Energy Changes,CMSEC)代替传统的模态应变能变化(Modal Strain Energy Changes, MSEC)建立先定位后定量的结构损伤识别两阶段法.与传统模态应变能(Modal St... 为提高结构损伤识别精度,采用跨模型模态应变能变化(Cross-model Modal Strain Energy Changes,CMSEC)代替传统的模态应变能变化(Modal Strain Energy Changes, MSEC)建立先定位后定量的结构损伤识别两阶段法.与传统模态应变能(Modal Strain Energy, MSE)计算时仅利用结构损伤后的振型不同,跨模型模态应变能(CMSE)的计算同时利用结构损伤前后的振型.先利用CMSEC构建CMSECI (Cross-model Modal Strain Energy Index)损伤指标来确定损伤位置,筛选出疑似损伤构件后,再利用CMSEC建立定量识别损伤程度的灵敏度方程.采用基于奇异值截断的迭代法求解该方程,以避免迭代过程中可能出现的病态方程问题.根据公式构成可以定性判断CMSEC比MSEC更难被噪声干扰.某简支梁算例表明,本文方法在损伤定位和损伤定量两个阶段均比传统方法具有更高的识别精度.为了深入考察本文方法的优越性,采用蒙特卡洛法从宏观的相对误差上界和具体的相对误差分布这两个视角解释了本文方法优于传统方法的原因. 展开更多
关键词 损伤识别 模态应变能 模态识别 结构健康监测 损伤灵敏度
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细长桁架臂卸载反弹动应力分布规律及试验
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作者 刘洋 付玲 +1 位作者 刘延斌 尹莉 《振动与冲击》 EI CSCD 北大核心 2024年第15期251-260,共10页
为研究细长桁架臂在卸载冲击下的动态响应变化规律,提出了基于等效梁振型函数的桁架臂动应力分布计算模型。根据等效梁振型函数,探讨了卸载后桁架臂动应力分布假设,分析了影响桁架臂卸载反弹动响应的相关参数。以装备细长桁架臂的动臂... 为研究细长桁架臂在卸载冲击下的动态响应变化规律,提出了基于等效梁振型函数的桁架臂动应力分布计算模型。根据等效梁振型函数,探讨了卸载后桁架臂动应力分布假设,分析了影响桁架臂卸载反弹动响应的相关参数。以装备细长桁架臂的动臂塔机为对象,建立了桁架臂精细化有限元模型和起重机刚柔耦合模型,通过仿真辨识了应力分布模型的关键参数。实施了动臂塔机系列载荷卸载冲击试验,桁架臂上主弦杆的动应力试验值与理论计算结果误差小于7%,表明动应力分布理论模型与实际相符。通过理论模型预测了极限工况下桁架臂上主弦杆动应力分布状态,发现在最大载荷卸载条件下起重臂动应力峰值超过结构承载极限,为卸载条件下起重机关键结构的优化设计提供依据。 展开更多
关键词 动应力分布模型 振型函数 桁架臂 刚柔耦合模型 卸载冲击试验
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基于NSGA-Ⅱ传感位置优化的曲面重构及误差补偿方法
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作者 尚秋峰 张晓旭 《光子学报》 EI CAS CSCD 北大核心 2024年第2期26-36,共11页
通过优化光纤布拉格光栅形状传感技术中传感点位置和补偿重构结果来提高薄层合金板三维形状重构精度。通过ANSYS workbench建立合金板仿真模型,提取应变和位移模态振型,根据模态置信准则、转换矩阵稳定性和模态振型相似性分别设计了三... 通过优化光纤布拉格光栅形状传感技术中传感点位置和补偿重构结果来提高薄层合金板三维形状重构精度。通过ANSYS workbench建立合金板仿真模型,提取应变和位移模态振型,根据模态置信准则、转换矩阵稳定性和模态振型相似性分别设计了三个目标函数,采用快速和精英机制的多目标遗传算法优化传感器位置。将镍钛合金板弯曲成不同曲率半径的弧形,利用光纤布拉格光栅中心波长漂移量和线性插值算法计算得出不同形状下的结构应变,重构合金板形状,均方根误差和最大误差相较于单目标优化算法分别减小30%和15%。利用粒子群优化径向基函数神经网络算法拟合误差与位移的关系实现误差补偿,均方根误差和最大误差比无补偿时分别减小了90%和70%,最大相对百分比误差仅为5%,提高了三维形状重构算法精度。 展开更多
关键词 光纤传感 光纤布拉格光栅 粒子群优化径向基函数 形状重构 模态法 多目标优化 误差补偿
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基于谐响应分析的冲击式水轮机转轮共振预测 被引量:1
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作者 王慧斌 李德友 +4 位作者 段雪晴 宫汝志 王洪杰 罗红英 李正贵 《大电机技术》 2024年第2期50-57,96,共9页
冲击式水轮机水斗的疲劳断裂与转轮的周期性振动密切相关。以六喷嘴冲击式水轮机模型机组转轮为研究对象,采用基于模态叠加的谐响应分析法,获取转轮在实际工作载荷激励下的形变与应力响应并评估薄弱部位,结合坎贝尔图确定共振转速。结... 冲击式水轮机水斗的疲劳断裂与转轮的周期性振动密切相关。以六喷嘴冲击式水轮机模型机组转轮为研究对象,采用基于模态叠加的谐响应分析法,获取转轮在实际工作载荷激励下的形变与应力响应并评估薄弱部位,结合坎贝尔图确定共振转速。结果表明,在实际运行工况下转轮三阶模态振型最易被激发,最大形变值为21.50mm,位于水斗尖端;七阶与八阶频率下被施加最大简谐载荷的水斗等效应力值较大,从根部向水斗尖端缺口处递减,最大应力值出现在分水刃根部,发生明显的应力集中;坎贝尔图显示易发生谐共振的转速为587r/min、660r/min、785r/min,在实际运行中应进一步测试与避免。 展开更多
关键词 冲击式水轮机 模态振型 谐响应分析 固有频率 坎贝尔图
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氦气轮机转子动力学特性优化设计
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作者 张帅杰 张靖煊 黄伟光 《汽轮机技术》 北大核心 2024年第3期175-178,共4页
基于ANSYS软件对某一型号的氦气轮机柔性转子进行了转子动力学特性的计算分析与优化设计。首先对转子的初始模型进行了临界转速计算,并识别影响转子固有频率的关键部位,通过加强其弯曲刚度,初步提高了转子的临界转速。进一步将转子分段... 基于ANSYS软件对某一型号的氦气轮机柔性转子进行了转子动力学特性的计算分析与优化设计。首先对转子的初始模型进行了临界转速计算,并识别影响转子固有频率的关键部位,通过加强其弯曲刚度,初步提高了转子的临界转速。进一步将转子分段并用柔性膜盘联轴器连接,计算得到氦气轮机转子的临界转速大幅提高,使其在设计转速下可视为刚性轴,保证了氦气轮机转子的转子动力学安全。 展开更多
关键词 氦气轮机转子 临界转速 模态振型 膜盘联轴器
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基于扣件弹条固有频率的扣压力检测与试验验证
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作者 丁正祥 曹子文 +4 位作者 柳明佳 刘林芽 韦征 胡浙泉 宋瑞 《城市轨道交通研究》 北大核心 2024年第9期154-159,共6页
[目的]扣件弹条的扣压力不足,会诱发周围扣件松脱,加剧轮轨之间的动力响应,影响轨道部件的使用寿命。相对于弹条缺失和断裂,弹条松脱较难通过常规的工人巡检发现,需要研究扣件弹条扣压力的检测方法。[方法]以高速铁路的WJ-7型扣件弹条为... [目的]扣件弹条的扣压力不足,会诱发周围扣件松脱,加剧轮轨之间的动力响应,影响轨道部件的使用寿命。相对于弹条缺失和断裂,弹条松脱较难通过常规的工人巡检发现,需要研究扣件弹条扣压力的检测方法。[方法]以高速铁路的WJ-7型扣件弹条为例,建立了扣件系统的精细化模型,分析了扣件弹条在不同扣压力状态下的模态特征,得到扣件弹条扣压力与固有频率的对应关系,进而提出通过测试弹条模态频率来推算扣压力的快速无损检测方法。选取我国某国家重点实验室轨道试验基地的高铁线路作为试验现场,对该检测方法进行试验验证。[结果及结论]不同扣压力状态下,弹条第1阶模态振型特征均表现为弹条两侧肢产生垂向振动和扭转;弹条第1阶固有频率仿真值与实测值差值比例绝对值的最大值为3.24%,可以认为该试验方法具有有效性。 展开更多
关键词 高速铁路 轨道结构 扣件弹条 扣压力 有限元分析 模态振型
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Influence of Trailing-Edge Wear on the Vibrational Behavior of Wind Turbine Blades
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作者 Yuanjun Dai Xin Wei +2 位作者 Baohua Li Cong Wang Kunju Shi 《Fluid Dynamics & Materials Processing》 EI 2024年第2期337-348,共12页
To study the impact of the trailing-edge wear on the vibrational behavior of wind-turbine blades,unworn blades and trailing-edge worn blades have been assessed through relevant modal tests.According to these experimen... To study the impact of the trailing-edge wear on the vibrational behavior of wind-turbine blades,unworn blades and trailing-edge worn blades have been assessed through relevant modal tests.According to these experiments,the natural frequencies of trailing-edge worn blades-1,-2,and-3 increase the most in the second to fourth order,thefifth order increases in the middle,and thefirst order increases the least.The damping ratio data indi-cate that,in general,thefirstfive-order damping ratios of trailing-edge worn blades-1 and trailing-edge worn blades-2 are reduced,and thefirstfive-order damping ratios of trailing-edge worn blades-3 are slightly improved.The mode shape diagram shows that the trailing-edge worn blades-1 and-2 have a large swing in the tip and the blade,whereas the second-and third-order vibration shapes of the trailing edge-worn blade-3 tend to be improved.Overall,all these results reveal that the blade’s mass and the wear area are the main fac-tors affecting the vibration characteristics of wind turbine blades. 展开更多
关键词 Wind turbine modal test natural frequency damping ratio mode shape
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基于高分辨率模态柔度矩阵桥梁损伤识别的少量传感器方法
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作者 马宏伟 郑晓杰 +2 位作者 夏子立 闫禹 聂振华 《湖南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2024年第7期127-136,共10页
为了降低监测系统成本和提高桥梁损伤识别精度,本文利用少量传感器获得高分辨率模态振型.在考虑路面粗糙度的情况下,基于柔度变化率进行损伤识别.在不同路面粗糙度水平下,对移动车辆荷载作用下桥梁上所测位移响应进行特征正交分解,再将... 为了降低监测系统成本和提高桥梁损伤识别精度,本文利用少量传感器获得高分辨率模态振型.在考虑路面粗糙度的情况下,基于柔度变化率进行损伤识别.在不同路面粗糙度水平下,对移动车辆荷载作用下桥梁上所测位移响应进行特征正交分解,再将得到的主成分矩阵中高频动力分量信息过滤,获得高分辨率的模态振型.利用少量传感器方法得到的高分辨率模态振型计算柔度变化率,将其作为桥梁损伤定位的指标.为了验证该方法的有效性,对一简支梁进行模拟和试验.结果显示,该方法在考虑不同粗糙度水平情况下,利用少量传感器得到高分辨率模态振型的柔度变化率能准确定位损伤. 展开更多
关键词 损伤识别 高分辨率模态振型 少量传感器 路面粗糙度 柔度矩阵
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基于模因理论-AHP的川东土家族文化主题民宿设计研究
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作者 牟彪 周纹汐 +1 位作者 徐鑫 陈勇勇 《家具与室内装饰》 北大核心 2024年第2期96-101,共6页
为传承和创新川东土家族文化,提升当地民宿品质,采用模因理论和AHP(Analytic Hierarchy Process)层次分析法,梳理文化特征,提取并筛选文化因子,基于形状文法对文化因子进行转译,生成新图形;提出了“引形赋新,装饰应用、形随物变,造型应... 为传承和创新川东土家族文化,提升当地民宿品质,采用模因理论和AHP(Analytic Hierarchy Process)层次分析法,梳理文化特征,提取并筛选文化因子,基于形状文法对文化因子进行转译,生成新图形;提出了“引形赋新,装饰应用、形随物变,造型应用、旧形新构,组合应用”等转译应用思路,并应用于民宿空间的界面分割、天花造型、门窗装饰,以及软硬装装饰等具体设计实践中。旨在为传承土家族文化,提升民宿品质,促进当地旅游经济发展作为参考。 展开更多
关键词 模因理论 层次分析法 形状文法 川东土家族文化 民宿设计
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基于激光多普勒测振的结构工作模态分析
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作者 吴伟 尹涵 +2 位作者 游超 丁飞 周萌 《工程抗震与加固改造》 北大核心 2024年第4期29-35,共7页
为验证激光多普勒测振仪快速识别高层建筑结构模态参数的适用性,提出一种采用两台远距离激光多普勒测振仪进行环境振动测试的方法。以一悬臂灯杆为例进行实测,获得振动速度响应。该方法实施便捷,测量精度能够满足要求。本文采用频域分解... 为验证激光多普勒测振仪快速识别高层建筑结构模态参数的适用性,提出一种采用两台远距离激光多普勒测振仪进行环境振动测试的方法。以一悬臂灯杆为例进行实测,获得振动速度响应。该方法实施便捷,测量精度能够满足要求。本文采用频域分解法(FDD)及随机子空间算法(SSI)对其模态参数进行了识别,为进一步应用于环境激励下的高层建筑等大型结构提供试验基础。结果表明,两种算法均可较好地获取结构自振频率及模态振型,自振频率差异很小,振型则几乎一致。并对灯杆进行简化的有限元分析,将模态识别结果与数值模拟结果相比,二者振型吻合较好,但自振频率略有差别。为避免模态遗漏和虚假模态,应结合多种模态识别算法进行模态分析。最后采用该方法对一超高层建筑进行环境激励下的振动实测与模态参数识别。 展开更多
关键词 激光多普勒 远距离测振 工作模态分析 随机子空间法 振型
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某型航空导叶作动筒振动性能仿真分析
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作者 曹洋 王鑫 +2 位作者 关思嘉 王泽坤 刘鹏举 《液压气动与密封》 2024年第6期34-39,共6页
针对航空导叶作动筒在复杂工况下的损坏问题,为在设计阶段预测产品可能出现的损坏,获取导叶作动筒标准载荷下的易损位置,利用有限元仿真建模方法建立了该型作动筒的模态分析、谐响应分析、随机振动分析与疲劳分析仿真模型。通过对数正... 针对航空导叶作动筒在复杂工况下的损坏问题,为在设计阶段预测产品可能出现的损坏,获取导叶作动筒标准载荷下的易损位置,利用有限元仿真建模方法建立了该型作动筒的模态分析、谐响应分析、随机振动分析与疲劳分析仿真模型。通过对数正弦扫频试验验证了模态分析仿真模型的准确性,获得了振型、固有频率与功率谱载荷下的应力响应等信息。考虑作动筒活塞的轴向伺服工作影响,在标准功率谱上叠加伺服工作正弦载荷模拟了该工况。建立随机振动情况下的疲劳寿命分析仿真模型,活塞与活塞密封圈的疲劳寿命结果在可接受范围内,为该航空作动筒结构优化设计提供了依据。 展开更多
关键词 导叶作动筒 模态分析 固有频率 振型 随机振动 疲劳寿命
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折弯角度及流体对汽车输流管路振动特性的影响研究
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作者 蔡小波 乔慧 +2 位作者 王杰 唐都 景亮彪 《汽车实用技术》 2024年第16期112-116,共5页
为了研究折弯角度和流体对汽车输流管路振动特性的影响,文章通过ANSYS work-bench分析软件,对不同折弯角度(90°、105°、120°、135°和150°)下的空管和充液管路的模态频率及模态振型进行仿真计算,并将输流管路... 为了研究折弯角度和流体对汽车输流管路振动特性的影响,文章通过ANSYS work-bench分析软件,对不同折弯角度(90°、105°、120°、135°和150°)下的空管和充液管路的模态频率及模态振型进行仿真计算,并将输流管路在不同工况下的模态频率进一步处理分析。结果表明,折弯角度的增加和流体的存在均会显著地降低输流管路的模态频率,而在低阶模态下,折弯角度和流体对输流管路模态振型的影响较弱。研究为后期汽车输流管路在充液和空管状态下的设计选型工作提供了依据。 展开更多
关键词 汽车输流管路 模态频率 模态振型 ANSYS workbench
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Application of Improved Hybrid Interface Substructural Component Modal Synthesis Method in Vibration Characteristics of Mistuned Blisk 被引量:5
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作者 BAI Bin BAI Guangchen LI Chao 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2014年第6期1219-1231,共13页
The large and complex structures are divided into hundreds of thousands or millions degrees of freedom(DOF) when they are calculated which will spend a lot of time and the efficiency will be extremely low. The class... The large and complex structures are divided into hundreds of thousands or millions degrees of freedom(DOF) when they are calculated which will spend a lot of time and the efficiency will be extremely low. The classical component modal synthesis method (CMSM) are used extensively, but for many structures in the engineering of high-rise buildings, aerospace systemic engineerings, marine oil platforms etc, a large amount of calculation is still needed. An improved hybrid interface substructural component modal synthesis method(HISCMSM) is proposed. The parametric model of the mistuned blisk is built by the improved HISCMSM. The double coordinating conditions of the displacement and the force are introduced to ensure the computational accuracy. Compared with the overall structure finite element model method(FEMM), the computational time is shortened by23.86%–31.56%and the modal deviation is 0.002%–0.157% which meets the requirement of the computational accuracy. It is faster 4.46%–10.57% than the classical HISCMSM. So the improved HISCMSM is better than the classical HISCMSM and the overall structure FEMM. Meanwhile, the frequency and the modal shape are researched, considering the factors including rotational speed, gas temperature and geometry size. The strong localization phenomenon of the modal shape’s the maximum displacement and the maximum stress is observed in the second frequency band and it is the most sensitive in the frequency veering. But the localization phenomenon is relatively weak in 1st and the 3d frequency band. The localization of the modal shape is more serious under the condition of the geometric dimensioning mistuned. An improved HISCMSM is proposed, the computational efficiency of the mistuned blisk can be increased observably by this method. 展开更多
关键词 modal shape mistuned blisk vibration characteristics computational efficiency computational accuracy
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Modal Strain Energy Based Structural Damage Localization for Offshore Platform using Simulated and Measured Data 被引量:5
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作者 WANG Shuqing LIU Fushun ZHANG Min 《Journal of Ocean University of China》 SCIE CAS 2014年第3期397-406,共10页
Modal strain energy based methods for damage detection have received much attention. However, most of published articles use numerical methods and some studies conduct modal tests with simple 1D or 2D structures to ve... Modal strain energy based methods for damage detection have received much attention. However, most of published articles use numerical methods and some studies conduct modal tests with simple 1D or 2D structures to verify the damage detection algorithms. Only a few studies utilize modal testing data from 3D frame structures. Few studies conduct performance comparisons between two different modal strain energy based methods. The objective of this paper is to investigate and compare the effectiveness of a traditional modal strain energy method(Stubbs index) and a recently developed modal strain energy decomposition(MSED) method for damage localization, for such a purpose both simulated and measured data from an offshore platform model being used. Particularly, the mode shapes used in the damage localization are identified and synthesized from only two measurements of one damage scenario because of the limited number of sensors. The two methods were first briefly reviewed. Next, using a 3D offshore platform model, the damage detection algorithms were implemented with different levels of damage severities for both single damage and multiple damage cases. Finally, a physical model of an offshore steel platform was constructed for modal testing and for validating the applicability. Results indicate that the MSED method outperforms the Stubbs index method for structural damage detection. 展开更多
关键词 offshore platform damage localization strain energy mode shapes modal testing
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An Improved Modal Strain Energy Method for Damage Detection in Offshore Platform Structures 被引量:3
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作者 Yingchao Li Shuqing Wang +1 位作者 Min Zhang Chunmei Zheng 《Journal of Marine Science and Application》 CSCD 2016年第2期182-192,共11页
The development of robust damage detection methods for offshore structures is crucial to prevent catastrophes caused by structural failures. In this research, we developed an Improved Modal Strain Energy (IMSE) meth... The development of robust damage detection methods for offshore structures is crucial to prevent catastrophes caused by structural failures. In this research, we developed an Improved Modal Strain Energy (IMSE) method for detecting damage in offshore platform structures based on a traditional modal strain energy method (the Stubbs index method). The most significant difference from the Stubbs index method was the application of modal frequencies. The goal was to improve the robustness of the traditional method. To demonstrate the effectiveness and practicality of the proposed IMSE method, both numerical and experimental studies were conducted for different damage scenarios using a jacket platform structure. The results demonstrated the effectiveness of the IMSE method in damage location when only limited, spatially incomplete, and noise-polluted modal data is available. Comparative studies showed that the IMSE index outperformed the Stubbs index and exhibited stronger robustness, confirming the superiority of the proposed approach. 展开更多
关键词 damage detection modal strain energy offshoreplatform structure modal frequency mode shape
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Experimental and FEM Modal Analysis of a Deployable-Retractable Wing 被引量:4
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作者 P. Jia S. K. Lai +1 位作者 W. Zhang C. W. Lim 《Modern Mechanical Engineering》 2014年第4期183-197,共15页
The aim of this paper is to conduct experimental modal analysis and numerical simulation to verify the structural characteristics of a deployable-retractable wing for aircraft and spacecraft. A modal impact test was c... The aim of this paper is to conduct experimental modal analysis and numerical simulation to verify the structural characteristics of a deployable-retractable wing for aircraft and spacecraft. A modal impact test was conducted in order to determine the free vibration characteristics. Natural frequencies and vibration mode shapes were obtained via measurement in LMS Test. Lab. The frequency response functions were identified and computed by force and acceleration signals, and then mode shapes of this morphing wing structure were subsequently identified by PolyMAX modal parameter estimation method. FEM modal analysis was also implemented and its numerical results convincingly presented the mode shape and natural frequency characteristics were in good agreement with those obtained from experimental modal analysis. Experimental study in this paper focuses on the transverse response of morphing wing as its moveable part is deploying or retreating. Vibration response to different rotation speeds have been collected, managed and analyzed through the use of comparison methodology with each other. Evident phenomena have been discovered including the resonance on which most analysis is focused because of its potential use to generate large amplitude vibration of specific frequency or to avoid such resonant frequencies from a wide spectrum of response. Manufactured deployable-retractable wings are studied in stage of experimental modal analysis, in which some nonlinear vibration resulted should be particularly noted because such wing structure displays a low resonant frequency which is always optimal to be avoided for structural safety and stability. 展开更多
关键词 Deployable-Retractable WING EXPERIMENTAL modal Analysis FEM Mode shapeS Natural Frequency LMS Test. Lab
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