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Structural reliability analysis and reliability-based design optimization: Recent advances

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Science China(Physics,Mechanics & Astronomy) 2013年第9期56卷 1611-1618页

作者： qiU ZhiPing HUANG Ren WANG XiaoJun qi wuchao Institute of Solid Mechanics Beihang University College of Aerospace Engineering Shenyang Aerospace University

We review recent research activities on structural reliability analysis,reliability-based design optimization(RBDO) and applications in complex engineering structural design.Several novel uncertainty propagation methods and reliability models,which are the basis of the reliability assessment,are given.In addition,recent developments on reliability evaluation and sensitivity analysis are highlighted as well as implementation strategies for RBDO.

关键词：结构可靠性分析设计优化工程结构设计可靠性模型可靠性评估敏感性分析可靠性评价研究活动

仿绿头鸭扑翼飞行器的低速飞行气动特性仿真研究

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无人系统技术 2024年第2期7卷 39-50页

作者：祁武超高展通田素梅沈阳航空航天大学辽宁省飞行器复合材料结构分析与仿真重点实验室沈阳110136

针对仿绿头鸭扑翼飞行器,在刚性扑动基础上引入了展向弯折和弦向扭转两种运动方式,提出了4种不同扑动路径的描述方程,并对其低速飞行气动特性进行了研究。首先,根据绿头鸭翼翅外形选择NACA 6411翼型并对其弯度和长度进行修正,通过放样... 详细信息

针对仿绿头鸭扑翼飞行器,在刚性扑动基础上引入了展向弯折和弦向扭转两种运动方式,提出了4种不同扑动路径的描述方程,并对其低速飞行气动特性进行了研究。首先,根据绿头鸭翼翅外形选择NACA 6411翼型并对其弯度和长度进行修正,通过放样创建扑翼几何构型。之后,基于动网格技术构建扑翼流场网格模型,包含刚性扑动、机翼弯折和机翼扭转等3种不同扑动形态。最后,使用Fluent进行瞬态仿真,基于压力耦合求解器和k-ω湍流模型得到不同扑动形态下飞行速度为2 m/s时的气动特性。结果表明,在低速飞行时,非对称扑动效应、展向弯折效应和弦向扭转效应均可起到增加升力、降低阻力的效果。所提出的3个扑动模型相对传统的对称刚性扑动模型分别能提高3.89%、14.78%、24.44%的升力,其中弯扭组合形式的扑动提供的推力能够抵消前飞时的空气阻力。

关键词：扑翼飞行器微小型飞行器仿生动网格柔性扑动气动特性

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带内埋质量超声速悬臂板的颤振特性

沈阳航空航天大学学报 2024年第2期41卷 1-13页

作者：祁武超俞浩洋田素梅刘宏亮沈阳航空航天大学辽宁省飞行器复合材料结构分析与仿真重点实验室沈阳110136

为提高具有内埋质量升力面的颤振速度,将其简化为带集中质量的矩形悬臂板。基于假设模态法和一阶活塞理论得到颤振模型,进而考察其颤振特性。首先,基于Kirchhoff薄板理论建立矩形悬臂板的结构动力学模型,并利用假设模态法得到带内埋质... 详细信息

为提高具有内埋质量升力面的颤振速度,将其简化为带集中质量的矩形悬臂板。基于假设模态法和一阶活塞理论得到颤振模型,进而考察其颤振特性。首先,基于Kirchhoff薄板理论建立矩形悬臂板的结构动力学模型,并利用假设模态法得到带内埋质量时的模态属性。其次,引入一阶活塞理论近似求解在超声速条件下的模态气动力,代入结构动力学模型得到颤振方程的时域表达。最后,通过引入指数形式的模态位移将颤振方程变换至频域并通过p-k法求解颤振速度和颤振频率。通过改变内埋件的位置、质量和数目等参数,得到其对超声速悬臂板颤振特性的影响规律。研究结果表明,在悬臂板前缘靠近翼梢区域内埋小质量物体可有效提高升力面的颤振速度,而在翼根附近,颤振速度对内埋质量的变化不敏感。

关键词：颤振内埋质量活塞理论假设模态法超声速悬臂板

A collocation interval analysis method for interval structural parameters and stochastic excitation

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Science China(Physics,Mechanics & Astronomy) 2012年第1期55卷 66-77页

作者： qi wuchao qiU ZhiPing Institute of Solid Mechanics Beijing University of Aeronautics and Astronautics Beijing 100191 China

Uncertainty propagation, one of the structural engineering problems, is receiving increasing attention owing to the fact that most significant loads are random in nature and structural parameters are typically subject to variation. In the study, the collocation interval analysis method based on the first class Chebyshev polynomial approximation is presented to investigate the least favorable responses and the most favorable responses of interval-parameter structures under random excitations. Compared with the interval analysis method based on the first order Taylor expansion, in which only information including the function value and derivative at midpoint is used, the collocation interval analysis method is a non-gradient algorithm using several collocation points which improve the precision of results owing to better approximation of a response function. The pseudo excitation method is introduced to the solving procedure to transform the random problem into a deterministic problem. To validate the procedure, we present numerical results concerning a building under seismic ground motion and aerofoil under continuous atmosphere turbulence to show the effectiveness of the collocation interval analysis method.

关键词：随机激励结构参数搭配区间分析方法 Chebyshev 不确定性传播地震地面运动多项式逼近

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大展弦比等剖面多段折叠翼颤振特性

兵工学报 2022年第12期43卷 3200-3210页

作者：田素梅张应鹏张贺铭祁武超沈阳航空航天大学航空发动机学院辽宁沈阳110136 沈阳航空航天大学辽宁省飞行器复合材料结构分析与仿真重点实验室辽宁沈阳110136

对大展弦比多段折叠翼的颤振特性进行研究,使用弯扭组合梁元模拟机翼弯曲和扭转两种变形形态,结合修正的气动片条理论,得到大展弦比机翼不同折叠姿态下的颤振速度和颤振频率数据。考虑到各段机翼折叠角的变化,基于有限元理论建立包含折... 详细信息

对大展弦比多段折叠翼的颤振特性进行研究,使用弯扭组合梁元模拟机翼弯曲和扭转两种变形形态,结合修正的气动片条理论,得到大展弦比机翼不同折叠姿态下的颤振速度和颤振频率数据。考虑到各段机翼折叠角的变化,基于有限元理论建立包含折叠角参数的结构动力学模型,并通过模态截断将其缩减并解耦。根据Theodorsen非定常气动力理论在频域内修正弯扭组合梁元上的气动升力和俯仰力矩,并基于V-g(V为机翼与未扰空气之间的相对速度,g为人工结构阻尼)法引入人工结构阻尼,对在不同折叠状态下的多段折叠翼进行颤振计算。研究结果表明:机翼结构的固有频率会随着折叠角的变化呈现非线性增长形态,而颤振速度和颤振频率随折叠角的变化规律基本相同,且外侧机翼折叠角的存在可有效提高机翼的颤振速度;当固定最外侧段机翼的折叠角时,机翼段数的增加对颤振速度的影响不明显。

关键词：颤振多段折叠翼大展弦比弯扭组合梁元

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镁合金带解锁装置热冲击断裂特性及拓扑优化

兵器装备工程学报 2023年第11期44卷 47-56页

作者：祁武超刘炳宏田素梅沈阳航空航天大学辽宁省飞行器复合材料结构分析与仿真重点实验室沈阳110136 沈阳航空航天大学航空发动机学院沈阳110136

分析了镁合金带解锁装置在发动机高温高压尾喷气流作用下的断裂特性并进行了拓扑优化设计。首先,构建了发动机喷管尾部受镁合金带阻挡的二维、可压缩、非定常流场分析模型,得到不同时刻镁合金带表面特征点处的压力曲线和温度曲线;其次,... 详细信息

分析了镁合金带解锁装置在发动机高温高压尾喷气流作用下的断裂特性并进行了拓扑优化设计。首先,构建了发动机喷管尾部受镁合金带阻挡的二维、可压缩、非定常流场分析模型,得到不同时刻镁合金带表面特征点处的压力曲线和温度曲线;其次,基于有限元法分别计算初始构型镁合金带在尾喷气流压力和温度共同作用下的响应,分析不同因素对镁合金带断裂特性的影响;之后,基于“薄弱环节”的思想设计了5种构型的镁合金带,并基于Johnson-Cook失效模型和瞬态分析过程分别得到其在热冲击环境下的断裂时间;最后,基于所发展的具有双层嵌套特征的变密度法对镁合金带中部受热冲击区域进行拓扑优化,以材料剩余体分比为优化变量并以规定的断裂时间为目标,得到镁合金带的最优拓扑构型。基于几何重构进行了验证,优化后的镁合金带能够满足设计要求。

关键词：镁合金带解锁装置热冲击断裂 Johnson-Cook失效模型拓扑优化

Recent advances in multifunctional shape memory photonic crystals and practical applications

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Nano Research 2024年第1期17卷 79-96页

作者： Yong qi Shufen Zhang State Key Laboratory of Fine Chemicals Frontier Science Center for Smart MaterialsDalian University of TechnologyDalian 116024China

Shape memory photonic crystals(SMPCs)are smart composite materials with changeable structural color integrated by shape memory polymer and photonic crystals.SMPC can produce one or more temporary shapes through nanoscale deformation,memorizing current states.SMPC can be recovered to their original shapes or some intermediate states under external stimuli,accompanied by the variation of structural color.As porous carriers with built-in sensing properties,SMPCs promoted the interdisciplinary development of nanophotonic technology in materials science,environmental engineering,biomedicine,chemical engineering,and mechanics.Herein,the recent progress on multifunctional SMPCs and practical applications,including traditional and cold programmable SMPCs,is summarized and discussed.The primary concern is shape programming at the nanoscale that has demonstrated numerous attractive functions,including smart sensing,ink-free printing,solvent detection,reprogrammable gradient wetting,and controllable bubble transportation,under variations of the surface nanostructure.It aims to figure out the nanoscale shape memory effects on structural color conversion and additional performance,inspiring the fabrication of the next generation of SMPCs.Finally,perspectives on future research directions and applications are also presented.It is believed that multifunctional SMPCs are powerful nanophotonic tools for the interdisciplinary development of numerous disciplines in the future.

关键词： photonic crystal shape memory structural color cold programmable shape recovery

Geometric Constraints for Global Regularity of 3D Shear Thickening Fluids

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Acta Mathematicae Applicatae Sinica 2024年第1期40卷 205-210页

作者： Jia-qi Yang Research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen518063China Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of SciencesBeijing100190China

We consider the relation between the direction of the vorticity and the global regularity of 3D shear thickening fluids.It is showed that a weak solution to the non-Newtonian incompressible fluid in the whole space is... 详细信息

关键词： direction of the vorticity non-Newtonian fluid global regularity

Understanding the spatial interaction of ultrasounds based on three-dimensional dual-frequency ultrasonic field numerical simulation

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China Foundry 2024年第1期21卷 29-43页

作者： Zhao-yang Yin qi-chi Le Yan-chao Jiang Da-zhi Zhao qi-yu Liao qi Zou Key Lab of Electromagnetic Processing of Materials Ministry of EducationNortheastern UniversityShenyang 110819China School of Materials Science and Engineering Northeastern UniversityShenyang 110819China

A transient 3D model was established to investigate the effect of spatial interaction of ultrasounds on the dual-frequency ultrasonic field in magnesium alloy melt.The effects of insertion depth and tip shape of the ultrasonic rods,input pressures and their ratio on the acoustic field distribution were discussed in detail.Additionally,the spacing,angle,and insertion depth of two ultrasonic rods significantly affect the interaction between distinct ultrasounds.As a result,various acoustic pressure distributions and cavitation regions are obtained.The spherical rods mitigate the longitudinal and transversal attenuation of acoustic pressure and expand the cavitation volume by 53.7%and 31.7%,respectively,compared to the plate and conical rods.Increasing the input pressure will enlarge the cavitation region but has no effect on the acoustic pressure distribution pattern.The acoustic pressure ratio significantly affects the pressure distribution and the cavitation region,and the best cavitation effect is obtained at the ratio of 2:1(P15:P20).

关键词： dual-frequency ultrasonic numerical model acoustic pressure spatial interaction magnesium alloy