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3D magnetotelluric inversions with unstructured finite-element and limited-memory quasi-Newton methods 被引量:8
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作者 Cao Xiao-Yue Yin Chang-Chun +3 位作者 Zhang Bo Huang Xin Liu Yun-He Cai Jing 《Applied Geophysics》 SCIE CSCD 2018年第3期556-565,共10页
Traditional 3D Magnetotelluric(MT) forward modeling and inversions are mostly based on structured meshes that have limited accuracy when modeling undulating surfaces and arbitrary structures. By contrast, unstructured... Traditional 3D Magnetotelluric(MT) forward modeling and inversions are mostly based on structured meshes that have limited accuracy when modeling undulating surfaces and arbitrary structures. By contrast, unstructured-grid-based methods can model complex underground structures with high accuracy and overcome the defects of traditional methods, such as the high computational cost for improving model accuracy and the difficulty of inverting with topography. In this paper, we used the limited-memory quasi-Newton(L-BFGS) method with an unstructured finite-element grid to perform 3D MT inversions. This method avoids explicitly calculating Hessian matrices, which greatly reduces the memory requirements. After the first iteration, the approximate inverse Hessian matrix well approximates the true one, and the Newton step(set to 1) can meet the sufficient descent condition. Only one calculation of the objective function and its gradient are needed for each iteration, which greatly improves its computational efficiency. This approach is well-suited for large-scale 3D MT inversions. We have tested our algorithm on data with and without topography, and the results matched the real models well. We can recommend performing inversions based on an unstructured finite-element method and the L-BFGS method for situations with topography and complex underground structures. 展开更多
关键词 Magnetotelluric(MT) 3D inversion UNSTRUCTURED fi nite-element method QUASI-NEWTON method L-BFGS
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Genetic algorithm-finite element method inversion of the factors determining the recent tectonic stress field of part of East Asia area
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作者 安美建 石耀霖 李方全 《Acta Seismologica Sinica(English Edition)》 EI CSCD 1998年第3期1-8,共8页
Genetic algorithm finite element method (GA FEM) is applied to the study of tectonic stress field of part of East Asia area. From the observed stress distribution, 2 D elastic plane stress inversion is made to dedu... Genetic algorithm finite element method (GA FEM) is applied to the study of tectonic stress field of part of East Asia area. From the observed stress distribution, 2 D elastic plane stress inversion is made to deduce the boundary forces and investigate controlling factors. It is suggested that the continent continent collision is the dominant factor controlling the Chinese tectonic stress field. The ocean continent convergence along the subduction zone is an important factor. There exists tensile boundary force along the marginal sea. 展开更多
关键词 genetic algorithm finite element method (GA FEM) tectonic stress field dynamic genetic algorithm inversion of finite element method
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Aerodynamic Design of Airfoils Based on Variable-Domain Variational Finite Element Method
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作者 陈池 刘高联 《Journal of Shanghai University(English Edition)》 CAS 2005年第3期210-215,共6页
Designing airfoils according to given pressure (or velocity) distribution is one kind of free boundary problems. Free boundary condition can be coupled with the flow governing equations by variable-domain variational ... Designing airfoils according to given pressure (or velocity) distribution is one kind of free boundary problems. Free boundary condition can be coupled with the flow governing equations by variable-domain variational calculus, which makes it possible to calculate simultaneously the flow field and the free boundary. An accurate deduction of the variable-domain variational principles is taken herein to design airfoils in compressible and incompressible flows. Furthermore, two grid types (H and O) are used in the calculation with better results for the O-type grid. It is shown that convergence is accelerated and good results can be obtained even if the initial guessed airfoil shape is a triangle, demonstrating the strong adaptability of this method. 展开更多
关键词 inverse design finite element method variable-domain variational principle.
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基于2.5D有限元的高密度电法不同装置勘探效果研究 被引量:1
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作者 赵荣春 吕玉增 +2 位作者 张智 韦柳椰 潘泓序 《煤田地质与勘探》 EI CAS CSCD 北大核心 2024年第4期128-136,共9页
高密度电法是一种适用性广泛的电阻率勘探方法,拥有多种电极排列装置选择。不同装置由于电极分布方式的差异,在针对不同地质目标和测区环境时往往表现出明显不同的探测能力。为探究各排列装置的特点及其适用情况,推导了2.5D电位的变分问... 高密度电法是一种适用性广泛的电阻率勘探方法,拥有多种电极排列装置选择。不同装置由于电极分布方式的差异,在针对不同地质目标和测区环境时往往表现出明显不同的探测能力。为探究各排列装置的特点及其适用情况,推导了2.5D电位的变分问题,采用Delaunay三角化算法实现了非结构化网格剖分,进而实现了有限元正演模拟。结合实践,对常见地质情况进行建模,分别使用温纳α、温纳β、施伦贝谢尔、偶极-偶极4种装置开展正反演对比研究。研究发现:(1)在探测未知区域单个异常体时,温纳β、施伦贝谢尔2种排列的效果更好;(2)在探测相邻较近的多个异常体时,应优先采用具有更高水平分辨率的施伦贝谢尔和偶极-偶极排列;(3)对于低阻破碎带的勘探,温纳β和偶极-偶极排列更为适用;(4)当地层具有较好分层界限时,4种排列均可体现良好的分层效果。因此,高密度电法勘探实践中应综合考虑不同排列装置的特点,根据具体情况选用合适的多种排列方式进行测量,并对采集数据进行综合对比分析,以获得更为准确的解释结果。 展开更多
关键词 高密度电法 非结构化网格 有限单元法 排列装置 正反演计算 电阻率
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基于逆有限元法的三维壁板结构变形场重构 被引量:1
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作者 胡明月 吴邵庆 董萼良 《工程力学》 EI CSCD 北大核心 2024年第6期235-245,共11页
过约束状态下的结构内部转角不连续,会导致结构变形场难以准确重构。该文以飞行器进气道典型三维壁板结构为对象,开展超静定状态下结构变形场重构方法研究。将子区域划分与逆有限元法相结合,实现了基于实测应变数据的超静定结构全场变... 过约束状态下的结构内部转角不连续,会导致结构变形场难以准确重构。该文以飞行器进气道典型三维壁板结构为对象,开展超静定状态下结构变形场重构方法研究。将子区域划分与逆有限元法相结合,实现了基于实测应变数据的超静定结构全场变形重构。对静载工况下三维壁板结构开展变形场重构数值仿真研究,验证算法的可行性和重构精度;进一步开展了试验研究,实现了变载荷工况下基于实测应变的三维壁板结构全场变形重构,并利用实测位移数据验证重构变形场的精度。试验结果表明:位移测点处的重构位移值与实测位移值的相对误差在10%左右,结合子区域划分和逆有限元法的变形重构算法可以准确重构出过约束工况下三维壁板结构的全场变形。 展开更多
关键词 工程力学 全场变形重构 逆有限元法 三维壁板结构 子区域划分
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基于逆有限元方法和位移振型函数的薄板动载荷识别方法
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作者 李可路 肖龙飞 +2 位作者 刘明月 寇雨丰 魏汉迪 《振动与冲击》 EI CSCD 北大核心 2024年第21期284-290,共7页
动载荷识别对于结构设计和健康监测具有重要意义。利用在工程实践中容易获得的应变响应,提出了一种基于逆有限元方法和位移振型函数的薄板动载荷识别方法,能够同时识别动载荷空间分布和时间历程。首先,逆有限元方法可以利用离散应变数... 动载荷识别对于结构设计和健康监测具有重要意义。利用在工程实践中容易获得的应变响应,提出了一种基于逆有限元方法和位移振型函数的薄板动载荷识别方法,能够同时识别动载荷空间分布和时间历程。首先,逆有限元方法可以利用离散应变数据重建离散位移场。然后,采用位移振型函数拟合得到连续位移场,将拟合良好的振型函数代入薄板微分控制方程中确定识别载荷。最后,通过薄板集中载荷和全局分布载荷识别的两个数值算例,验证该方法的可行性和准确性。结果表明,提出方法对于薄板动载荷的识别是有效且准确的。 展开更多
关键词 动载荷识别 应变响应 薄板 逆有限元方法 位移振型
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热载荷下星载天线逆有限元变形重构方法
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作者 顾叶青 操卫忠 +4 位作者 袁慎芳 孙为民 黄欣婷 黄天翔 冯健 《东南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2024年第4期997-1004,共8页
为实现星载天线结构在服役过程中的实时变形监测,针对真实分布式热载荷下的星载天线板结构,研究了基于应变监测的逆有限元变形重构方法.首先,针对星载天线板结构提出了一种基于四节点四边形逆向壳单元的变形监测方法,通过建立基于位移... 为实现星载天线结构在服役过程中的实时变形监测,针对真实分布式热载荷下的星载天线板结构,研究了基于应变监测的逆有限元变形重构方法.首先,针对星载天线板结构提出了一种基于四节点四边形逆向壳单元的变形监测方法,通过建立基于位移梯度的单元划分方法,对逆有限元单元划分进行优化,采用最小二乘误差函数构造结构应变与位移的矩阵关系.其次,建立天线板热试验系统,获取典型热载荷下的结构温度分布.然后,建立典型实验温差状态下的复合材料星载天线板结构有限元模型,获取结构表面应变和位移.最后,在典型热载荷下,验证所提变形重构方法的有效性.结果表明,变形重构的位移误差不超过0.5 mm,说明逆有限元法能够在典型热载荷下准确重构天线板变形. 展开更多
关键词 星载天线 分布式热载荷 逆有限元法 变形重构
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基于逆有限元法的结构位移与应变场反演方法
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作者 岳应萍 吴国庆 +3 位作者 蒋镇涛 曾捷 朱清峰 陈国材 《传感器与微系统》 CSCD 北大核心 2024年第7期114-117,共4页
舰船梯形结构作为封盖船体或将其分隔成层的平面板状结构,对于保证船体强度及不沉性具有重要作用。梯形结构受力不均匀会产生巨大拉扯力,易造成梯形结构变形与疲劳应力集中。基于此,本文提出研究一种基于逆有限元法(iFEM)和光纤应变感... 舰船梯形结构作为封盖船体或将其分隔成层的平面板状结构,对于保证船体强度及不沉性具有重要作用。梯形结构受力不均匀会产生巨大拉扯力,易造成梯形结构变形与疲劳应力集中。基于此,本文提出研究一种基于逆有限元法(iFEM)和光纤应变感知的舰船梯形结构位移与应变场反演方法,并给出了相应光纤Bragg光栅(FBG)传感器布局形式。利用Ansys有限元分析方法,开展了基于仿真结果的相关反演方法验证。在此基础上,构建了基于光纤传感器的梯形结构位移、应变分布监测与反演实验系统。研究表明,双端固支梯形结构的位移重构均方根误差(RMSE)为0.076,应变场重构平均相对误差为6.59%。本文所提方法突破了iFEM因形函数阶次低而无法直接求解结构应变场的难题,能够为舰船梯形结构健康监测与舰载武器基座位姿精度提升提供技术支撑。 展开更多
关键词 逆有限元法 梯形结构 光纤BRAGG光栅传感器 位移 应变场反演
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基于现场实测反演的地铁运行诱发邻近结构振动预测
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作者 吴德顺 顾晓强 +2 位作者 刘鑫 岳建勇 王平山 《结构工程师》 2024年第5期36-44,共9页
准确预测地铁运行引起的拟建结构振动具有重要的理论意义和工程应用价值。目前现场实测主要用于验证数值模拟的准确性,较少直接用于数值模型校准。为解决拟建结构振动预测难的问题,提出了基于地下室建成前地表振动实测和有限元模拟的地... 准确预测地铁运行引起的拟建结构振动具有重要的理论意义和工程应用价值。目前现场实测主要用于验证数值模拟的准确性,较少直接用于数值模型校准。为解决拟建结构振动预测难的问题,提出了基于地下室建成前地表振动实测和有限元模拟的地铁运行诱发振动频域反演预测方法。首先,开展了地下室建成前地铁运行引起的场地振动实测,然后由隧道-分层地基有限元模型计算场地振动传递函数。结合传递函数原理和地表实测反演得到振源。随后,将反演振源输入含地下室结构的有限元模型,开展振动预测分析。结果表明,预测的地下室振动与实测结果吻合良好,提出的方法可为地铁运行引起拟建结构振动的准确预测提供重要的支撑。 展开更多
关键词 振动 现场实测 反演 动力有限元 地铁隧道
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高压电力电缆土壤导热系数的反演与计算
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作者 覃喜 周文俊 +2 位作者 吕鸣 姜玉菡 杨仕友 《电工电能新技术》 CSCD 北大核心 2024年第9期94-102,共9页
温度和载流量是电缆运行状态及热稳定极限的重要指标参数,精确的土壤导热系数是电缆温度场准确计算的前提和基础。土壤导热系数受多种因素影响,呈现较大差异性和不确定性。为精确计算高压电力电缆实际运行工况下的温度场和载流量,本文... 温度和载流量是电缆运行状态及热稳定极限的重要指标参数,精确的土壤导热系数是电缆温度场准确计算的前提和基础。土壤导热系数受多种因素影响,呈现较大差异性和不确定性。为精确计算高压电力电缆实际运行工况下的温度场和载流量,本文提出了电力电缆实时土壤导热系数逆问题的数学模型和计算方法。开发了电缆表皮温度测量的分布式光纤测温系统,基于电缆表面采样点实时温度构建了分层土壤实时导热系数反演数学模型,并提出逆问题求解的改进遗传算法。实例计算结果表明,应用本文成果计算的实时或动态载流量比标称载流量高出38.08%。 展开更多
关键词 逆问题 改进遗传算法 有限元 导热系数
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Toward Improved Accuracy in Quasi-Static Elastography Using Deep Learning
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作者 Yue Mei Jianwei Deng +4 位作者 Dongmei Zhao Changjiang Xiao Tianhang Wang Li Dong Xuefeng Zhu 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第4期911-935,共25页
Elastography is a non-invasive medical imaging technique to map the spatial variation of elastic properties of soft tissues.The quality of reconstruction results in elastography is highly sensitive to the noise induce... Elastography is a non-invasive medical imaging technique to map the spatial variation of elastic properties of soft tissues.The quality of reconstruction results in elastography is highly sensitive to the noise induced by imaging measurements and processing.To address this issue,we propose a deep learning(DL)model based on conditional Generative Adversarial Networks(cGANs)to improve the quality of nonhomogeneous shear modulus reconstruction.To train this model,we generated a synthetic displacement field with finite element simulation under known nonhomogeneous shear modulus distribution.Both the simulated and experimental displacement fields are used to validate the proposed method.The reconstructed results demonstrate that the DL model with synthetic training data is able to improve the quality of the reconstruction compared with the well-established optimization method.Moreover,we emphasize that our DL model is only trained on synthetic data.This might provide a way to alleviate the challenge of obtaining clinical or experimental data in elastography.Overall,this work addresses several fatal issues in applying the DL technique into elastography,and the proposed method has shown great potential in improving the accuracy of the disease diagnosis in clinical medicine. 展开更多
关键词 Nonhomogeneous elastic property distribution reconstruction deep learning finite element method inverse problem ELASTOGRAPHY conditional generative adversarial network
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基于三节点逆元法与光纤传感器的机翼形态重构方法
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作者 岳应萍 赵悦琦 +2 位作者 曾捷 王志刚 杨宇 《航空科学技术》 2024年第5期101-109,共9页
基于应变信息的飞机机翼结构形态重构技术,可为“仿生式机翼”的气动外形、气弹特性以及隐身性能控制提供数据支撑。为实现对飞机机翼的变形监测,本文提出一种基于三节点逆有限元法和应变信息采集的形态重构方法,并给出相应的光频域反... 基于应变信息的飞机机翼结构形态重构技术,可为“仿生式机翼”的气动外形、气弹特性以及隐身性能控制提供数据支撑。为实现对飞机机翼的变形监测,本文提出一种基于三节点逆有限元法和应变信息采集的形态重构方法,并给出相应的光频域反射型分布式光纤传感器布局形式。首先,建立飞机机翼简化模型,开展基于有限元分析结果的形态重构方法仿真验证。其次,构建基于分布式光纤传感器的机翼简化模型应变监测与形态重构试验系统。研究表明,自然下垂工况下,机翼简化模型形态重构相对误差平均值约为4.01%;弯扭组合工况下,机翼简化模型形态重构相对误差平均值约为6.34%。本文所提方法适用于不同载荷工况下飞机机翼变形监测,能够为可变体机翼形态调控与机载共型天线相位补偿提供帮助。 展开更多
关键词 逆有限元法 机翼简化模型 光频域反射型 分布式光纤传感器 形态重构
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AN UPDATING METHOD FOR LOCAL MODEL ERRORS
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作者 李书 冯太华 范绪箕 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 1995年第2期129-133,共5页
The location of model errors in a stiffness matrix by using test data has been investigated by the others.The present paper deals with the problem of updating stiffness elements in the erroneous areas. Firstly,a model... The location of model errors in a stiffness matrix by using test data has been investigated by the others.The present paper deals with the problem of updating stiffness elements in the erroneous areas. Firstly,a model that bears relation to erroneous elements only is derived.This model is termed local errors model,which reduces orders and computational loads compared with global stiffness matrix. Secondly,an inverse eigenvalue method is used to update model errors. The results of a numerical experiment demonstrate that the method is quite effective. 展开更多
关键词 finite element methods STRUCTURES inverse problem updating method MODEL
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基于逆有限元法的船体加筋板结构位移场重构
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作者 孙良晖 张慧虹 +1 位作者 李至华 张猛 《船舶工程》 CSCD 北大核心 2024年第7期50-57,共8页
在船舶遭遇事故时,加筋板是最先受到载荷的结构,为了解该结构在动载荷作用下的位移场,以船体加筋板结构为对象,通过逆有限元法(iFEM)对结构在时域动态载荷作用下的位移场进行重构。先对其进行模态分析,确定其固有频率后对结构施加频率超... 在船舶遭遇事故时,加筋板是最先受到载荷的结构,为了解该结构在动载荷作用下的位移场,以船体加筋板结构为对象,通过逆有限元法(iFEM)对结构在时域动态载荷作用下的位移场进行重构。先对其进行模态分析,确定其固有频率后对结构施加频率超过1阶固有频率的动态载荷,然后进行有限元动态响应模拟,将得到的节点位移结果作为参考解,并将应变数据作为逆有限元输入应变数据进行位移场重构。提出一种较精确的测点布置方案,与其他数量相近但布置方式不同的测点布置方案相比,该测点布置方案的位移场重构误差降低了一半以上,总体保持在5%以内。 展开更多
关键词 逆有限元法 船体加筋板 位移场重构 iQS4逆单元 模态分析
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基于多区多求解器的金属-介质复合目标电磁散射特性分析
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作者 刘露 邓世豪 +2 位作者 米晓林 江明 杨毅 《制导与引信》 2024年第3期46-53,共8页
在导弹类金属-介质复合目标电磁散射特性求解过程中,采用常规迭代求解方法存在难以收敛以及内迭代边界积分区域重复求解的问题。针对该问题,在传统有限元边界积分区域分解法(finite element boundary integral domain decomposition met... 在导弹类金属-介质复合目标电磁散射特性求解过程中,采用常规迭代求解方法存在难以收敛以及内迭代边界积分区域重复求解的问题。针对该问题,在传统有限元边界积分区域分解法(finite element boundary integral domain decomposition method,FE-BI-DDM)的基础上,采用了更为灵活的多区多求解器的方法(multi domain multi solver method,MDMSM)。该方法对导弹类金属-介质复合目标中难以收敛的金属区域,使用快速直接求逆的方法求解,由于可以使用独立的网格模型进行电磁建模,避免了内迭代部分的模型重复建立过程,从而大幅减少了整体模型求解时间。实验结果表明:所提方法可以在相同计算精度的条件下,以不过多增加内存空间为前提,大幅缩短了导弹类目标的金属-介质复合模型的电磁求解时间。该方法为开展导弹类目标特性分析提供了一条可行的技术途径。 展开更多
关键词 有限元边界积分区域分解法 多区多求解器方法 金属-介质复合目标 迭代求解 快速直接求解
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Inverse analysis of laboratory data and observations for evaluation of backward erosion piping process 被引量:2
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作者 Sige Peng John D.Rice 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2020年第5期1080-1092,共13页
An inverse analysis procedure has been developed to interpret collected pore pressure data and observations during backward erosion piping(BEP)initiation and progression in sandy soils.The procedure has been applied t... An inverse analysis procedure has been developed to interpret collected pore pressure data and observations during backward erosion piping(BEP)initiation and progression in sandy soils.The procedure has been applied to laboratory models designed to mimic the initiation and progression of BEP through a constricted vertical outlet.The inverse analysis uses three-dimensional(3D)finite element method(FEM)to successively produce models of the hydraulic head regime surrounding progressive stages of BEP based on observations at the sample surface and pore pressure measurements obtained from the laboratory models.The inverse analysis results in a series of 3D contour plots that represent the hydraulic-head regime at each stage of the BEP development,allowing for assessing the development of BEP mechanism as well as calculating the critical hydraulic conditions required for various BEP stages to initiate and progress.Interpretation of the results identified four significant stages of the piping process:(1)loosened zone initiation,(2)channel initiation and progression,(3)riser sand fluidization,and(4)loosened zone progression.Interpretation of the hydraulic head contour plots allows assessment of the critical hydraulic gradients needed to initiate and progress various components of the BEP development. 展开更多
关键词 Backward erosion piping(BEP) Laboratory modeling inverse analysis finite element method(FEM) Soil loosening Critical gradient
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Nonlinear Inversion for Complex Resistivity Method Based on QPSO-BP Algorithm 被引量:1
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作者 Weixin Zhang Jinsuo Liu +1 位作者 Le Yu Biao Jin 《Open Journal of Geology》 2021年第10期494-508,共15页
The significant advantage of the complex resistivity method is to reflect the abnormal body through multi-parameters, but its inversion parameters are more than the resistivity tomography method. Therefore, how to eff... The significant advantage of the complex resistivity method is to reflect the abnormal body through multi-parameters, but its inversion parameters are more than the resistivity tomography method. Therefore, how to effectively invert these spectral parameters has become the focused area of the complex resistivity inversion. An optimized BP neural network (BPNN) approach based on Quantum Particle Swarm Optimization (QPSO) algorithm was presented, which was able to improve global search ability for complex resistivity multi-parameter nonlinear inversion. In the proposed method, the nonlinear weight adjustment strategy and mutation operator were used to enhance the optimization ability of QPSO algorithm. Implementation of proposed QPSO-BPNN was given, the network had 56 hidden neurons in two hidden layers (the first hidden layer has 46 neurons and the second hidden layer has 10 neurons) and it was trained on 48 datasets and tested on another 5 synthetic datasets. The training and test results show that BP neural network optimized by the QPSO algorithm performs better than the BP neural network without initial optimization on the inversion training and test models, and the mean square error distribution is better. At the same time, a double polarized anomalous bodies model was also used to verify the feasibility and effectiveness of the proposed method, the inversion results show that the QPSO-BP algorithm inversion clearly characterizes the anomalous boundaries and is closer to the values of the parameters. 展开更多
关键词 Complex Resistivity finite element method Nonlinear Inversion QPSO-BP Algorithm 2.5D Numerical Simulation
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Unsteady Inverse Problem of Type B for 2-D Transonic Flow: A Variational Formulation
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作者 Liu Gaolian (Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University) 《Advances in Manufacturing》 SCIE CAS 1999年第1期1-3,共3页
A family of variational principles (VP) has been developed for the unsteady inverse problem of the second type I B. It opens new ways for the inverse shape design of unsteady airfoils and can serve as key basis of m... A family of variational principles (VP) has been developed for the unsteady inverse problem of the second type I B. It opens new ways for the inverse shape design of unsteady airfoils and can serve as key basis of multipoint inverse shape design of steady airfoils and cascades. 展开更多
关键词 AERODYNAMICS transonic airfoil unsteady flow inverse problem finite element method variational principle
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Improved Particle Swarm Optimization for Solving Transient Nonlinear Inverse Heat Conduction Problem in Complex Structure
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作者 ZHOU Ling ZHANG Chunyun +2 位作者 BAI Yushuai LIU Kun CUI Miao 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2021年第5期816-828,共13页
Accurately solving transient nonlinear inverse heat conduction problems in complex structures is of great importance to provide key parameters for modeling coupled heat transfer process and the structure’s optimizati... Accurately solving transient nonlinear inverse heat conduction problems in complex structures is of great importance to provide key parameters for modeling coupled heat transfer process and the structure’s optimization design.The finite element method in ABAQUS is employed to solve the direct transient nonlinear heat conduction problem.Improved particle swarm optimization(PSO)method is developed and used to solve the transient nonlinear inverse problem.To investigate the inverse performances,some numerical tests are provided.Boundary conditions at inaccessible surfaces of a scramjet combustor with the regenerative cooling system are inversely identified.The results show that the new methodology can accurately and efficiently determine the boundary conditions in the scramjet combustor with the regenerative cooling system.By solving the transient nonlinear inverse problem,the improved particle swarm optimization for solving the transient nonlinear inverse heat conduction problem in a complex structure is verified. 展开更多
关键词 improved particle swarm optimization transient nonlinear heat conduction problem inverse identification finite element method complex structure
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Inverse Problems for an Euler-Bernoulli Beam: Identification of Bending Rigidity and External Loads
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作者 Hiroaki Katori 《World Journal of Mechanics》 2018年第5期192-199,共8页
We present a method for identifying the flexural rigidity and external loads acting on a beam using the finite-element method. We used mixed beam elements possessing transverse deflection and the bending moment as the... We present a method for identifying the flexural rigidity and external loads acting on a beam using the finite-element method. We used mixed beam elements possessing transverse deflection and the bending moment as the primary degrees of freedom. The first step is to determine the bending moment from the transverse deflection and boundary conditions. The second step is to substitute the bending moment into the final equations with respect to the unknown parameters (flexural rigidity or external load). The final step solves the resulting system of equations. We apply this method to some inverse beam problems and provide an accurate estimation. Several numerical examples are performed and show that present method gives excellent results for identifying bending stiffness and distributed load of beam. 展开更多
关键词 inverse PROBLEM BEAM finite-element method STRUCTURAL IDENTIFICATION
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