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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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A novel method of rapidly modeling optical properties of actual photonic crystal fibres 被引量:2
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作者 王立文 娄淑琴 +1 位作者 陈卫国 李宏雷 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第8期1-7,共7页
The flexible structure of photonic crystal fibre not only offers novel optical properties but also brings some difficulties in keeping the fibre structure in the fabrication process which inevitably cause the optical ... The flexible structure of photonic crystal fibre not only offers novel optical properties but also brings some difficulties in keeping the fibre structure in the fabrication process which inevitably cause the optical properties of the resulting fibre to deviate from the designed properties. Therefore, a method of evaluating the optical properties of the actual fibre is necessary for the purpose of application. Up to now, the methods employed to measure the properties of the actual photonic crystal fibre often require long fibre samples or complex expensive equipments. To our knowledge, there are few studies of modeling an actual photonic crystal fibre and evaluating its properties rapidly. In this paper, a novel method, based on the combination model of digital image processing and the finite element method, is proposed to rapidly model the optical properties of the actual photonic crystal fibre. Two kinds of photonic crystal fibres made by Crystal Fiber A/S are modeled. It is confirmed from numerical results that the proposed method is simple, rapid and accurate for evaluating the optical properties of the actual photonic crystal fibre without requiring complex equipment. 展开更多
关键词 photonic crystal fibre digital image processing finite element method modeling optical properties
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A New 3D Meso-mechanical Modeling Method of Coral Aggregate Concrete Considering Interface Characteristics 被引量:1
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作者 CHEN Boyu YU Hongfa ZHANG Jinhua 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2022年第S01期98-105,共8页
On the basis of the three-dimensional(3D)random aggregate&mortar two-phase mesoscale finite element model,C++programming was used to identify the node position information of the interface between the aggregate an... On the basis of the three-dimensional(3D)random aggregate&mortar two-phase mesoscale finite element model,C++programming was used to identify the node position information of the interface between the aggregate and mortar elements.The nodes were discretized at this position and the zero-thickness cohesive elements were inserted.After that,the crack energy release rate fracture criterion based on the fracture mechanics theory was assigned to the failure criterion of the interface transition zone(ITZ)elements.Finally,the three-phase mesomechanical model based on the combined finite discrete element method(FDEM)was constructed.Based on this model,the meso-crack extension and macro-mechanical behaviour of coral aggregate concrete(CAC)under uniaxial compression were successfully simulated.The results demonstrated that the meso-mechanical model based on FDEM has excellent applicability to simulate the compressive properties of CAC. 展开更多
关键词 coral aggregate concrete(CAC) finite discrete element method 3D meso-mechanical model fracture cracks C++
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A Theory and Method for Modeling of Structures with Stochastic Parameters
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作者 ZHANG Bei YIN Xue-gang WANG Fu-ming ZHONG Yan-hui CAI Ying-chun 《上海交通大学学报》 EI CAS CSCD 北大核心 2004年第z2期194-198,共5页
In order to reflect the stochastic characteristics of structures more comprehensively and accurately, a theory and method for modeling of structures with stochastic parameters is presented by using probability finite ... In order to reflect the stochastic characteristics of structures more comprehensively and accurately, a theory and method for modeling of structures with stochastic parameters is presented by using probability finite element method and stochastic experiment data of structures based on the modeling of structures with deterministic parameters. Double-decker space frame is taken as an example to validate this theory and method, good results are gained. 展开更多
关键词 PROBABILITY finite element method STOCHASTIC PARAMETER structure modeling
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Evaluation of interfacial properties in SiC composites using an improved cohesive element method 被引量:2
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作者 Hang Zang Xing-Qing Cao +2 位作者 Chao-Hui He Zhi-Sheng Huang Yong-Hong Li 《Nuclear Science and Techniques》 SCIE CAS CSCD 2018年第2期82-90,共9页
A two-dimensional axisymmetric finite element model based on an improved cohesive element method was developed to simulate interfacial debonding, sliding friction, and residual thermal stresses in SiC composites durin... A two-dimensional axisymmetric finite element model based on an improved cohesive element method was developed to simulate interfacial debonding, sliding friction, and residual thermal stresses in SiC composites during single-fiber push-out tests to extract the interfacial bond strength and frictional stress. The numerical load–displacement curves agree well with experimental curves,indicating that this cohesive element method can be used for calculating the interfacial properties of SiC composites.The simulation results show that cracks are most likely to occur at the ends of the experimental sample, where the maximum shear stress is observed and that the interfacial shear strength and constant sliding friction stress decrease with an increase in temperature. Moreover, the load required to cause complete interfacial failure increases with the increase in critical shear strength, and the composite materials with higher fiber volume fractions have higher bearing capacities. In addition, the initial failure load increases with an increase in interphase thickness. 展开更多
关键词 Fiber push-out test COHESIVE element model SiC composites finite element method INTERFACIAL properties
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Critical Void Volume Fraction Identification Based on Mesoscopic Damage Model for NVA Shipbuilding Steel 被引量:1
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作者 Zijie Song Zhiqiang Hu Jonas W.Ringsberg 《Journal of Marine Science and Application》 CSCD 2019年第4期444-456,共13页
NVA mild steel is a commonly used material in the shipbuilding industry.An accurate model for description of this material’s ductile fracture behaviour in numerical simulation is still a challenging task.In this pape... NVA mild steel is a commonly used material in the shipbuilding industry.An accurate model for description of this material’s ductile fracture behaviour in numerical simulation is still a challenging task.In this paper,a new method for predicting the critical void volume fraction fc in the Guson-Tvergaard-Needleman(GTN)model is introduced to describe the ductile fracture behaviour of NVA shipbuilding mild steel during ship collision and grounding scenarios.Most of the previous methods for determination of the parameter fc use a converse method,which determines the values of the parameters through comparisons between experi-mental results and numerical simulation results but with high uncertainty.A new method is proposed based on the Hill,Bressan,and Williams hypothesis,which reduces the uncertainty to a satisfying extent.To accurately describe the stress-strain relationship of materials before and after necking,a combination of the Voce and Swift models is used to describe the material properties of NVA mild steel.A user-defined material subroutine has been developed to enable the application of the new parameter deter-mination method and its implementation in the finite element software LS-DYNA.It is observed that the model can accurately describe structural damage by comparing the numerical simulation results with those of experiments;thus,the results demon-strate the model’s capacity for structural response prediction in ship collision and grounding scenario simulations。 展开更多
关键词 Ship collision and grounding Guson-Tvergaard-Needleman model NVA steel Ductile fracture finite element method
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Fatigue Analysis of Steel Catenary Risers Based on a Plasticity Model 被引量:1
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作者 Yongqiang Dong Liping Sun 《Journal of Marine Science and Application》 CSCD 2015年第1期76-82,共7页
The most critical issue in the steel catenary riser design is to evaluate the fatigue damage in the touchdown zone accurately. Appropriate modeling of the riser-soil resistance in the touchdown zone can lead to signif... The most critical issue in the steel catenary riser design is to evaluate the fatigue damage in the touchdown zone accurately. Appropriate modeling of the riser-soil resistance in the touchdown zone can lead to significant cost reduction by optimizing design. This paper presents a plasticity model that can be applied to numerically simulate riser-soil interaction and evaluate dynamic responses and the fatigue damage of a steel catenary riser in the touchdown zone. Utilizing the model, numerous riser-soil elements are attached to the steel catenary riser finite elements, in which each simulates local foundation restraint along the riser touchdown zone. The riser-soil interaction plasticity model accounts for the behavior within an allowable combined loading surface. The model will be represented in this paper, allowing simple numerical implementation. More importantly, it can be incorporated within the structural analysis of a steel catenary riser with the finite element method. The applicability of the model is interpreted theoretically and the results are shown through application to an offshore 8.625 steel catenary riser example. The fatigue analysis results of the liner elastic riser-soil model are also shown. According to the comparison results of the two models, the fatigue life analysis results of the plasticity framework are reasonable and the horizontal effects of the riser-soil interaction can be included. 展开更多
关键词 steel catenary riser fatigue analysis riser-soil interaction plasticity model finite element method
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Damage Detection in Reinforced Concrete Berthing Jetty Using a Plasticity Model Approach
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作者 Srinivasan Chandrasekaran P.T.Ajesh Kumar 《Journal of Marine Science and Application》 CSCD 2019年第4期482-491,共10页
A conventional method of damage modeling by a reduction in stiffness is insufficient to model the complex non-linear damage characteristics of concrete material accurately.In this research,the concrete damage plastici... A conventional method of damage modeling by a reduction in stiffness is insufficient to model the complex non-linear damage characteristics of concrete material accurately.In this research,the concrete damage plasticity constitutive model is used to develop the numerical model of a deck beam on a berthing jetty in the Abaqus finite element package.The model constitutes a solid section of 3D hexahedral brick elements for concrete material embedded with 2D quadrilateral surface elements as reinforcements.The model was validated against experimental results of a beam of comparable dimensions in a cited literature.The validated beam model is then used in a three-point load test configuration to demonstrate its applicability for preliminary numerical evaluation of damage detection strategy in marine concrete structural health monitoring.The natural frequency was identified to detect the presence of damage and mode shape curvature was found sensitive to the location of damage. 展开更多
关键词 Structural health monitoring Damage detection natural frequency Mode shape CURVATURE Damage parameters Concrete damaged plasticity model finite element method Numericalmodel
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Experimental and Numerical Investigations on Vibration Characteristics of a Loaded Ship Model
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作者 Pu Liang Ming Hong Zheng Wang 《Journal of Marine Science and Application》 CSCD 2015年第3期234-243,共10页
In this paper, the vibration characteristics of the structure in the finite fluid domain are analyzed using a coupled finite element method. The added mass matrix is calculated with finite element method (FEM) by 8-... In this paper, the vibration characteristics of the structure in the finite fluid domain are analyzed using a coupled finite element method. The added mass matrix is calculated with finite element method (FEM) by 8-node acoustic fluid elements. The vibration characteristics of the structure in the finite fluid domain are calculated combining structure FEM mass matrix. By writing relevant programs, the numerical analysis on vibration characteristics of a submerged cantilever rectangular plate in finite fluid domain and loaded ship model is performed. A modal identification experiment for the loaded ship model in air and in water is conducted and the experiment results verify the reliability of the numerical analysis. The numerical method can be used for further research on vibration characteristics and acoustic radiation problems of the structure in the finite fluid domain. 展开更多
关键词 loaded ship model vibration characteristics finite element method (FEM) added mass matrix natural frequency modal identification finite fluid domain
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Bridge Engineering-Oriented Parametric Model
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作者 周凌远 李乔 《Journal of Southwest Jiaotong University(English Edition)》 2004年第1期61-64,共4页
A new model is proposed to improve the efficiency of structural modeling. In this model, the bridge structural components are expressed with component description, parametric description and geometric description in a... A new model is proposed to improve the efficiency of structural modeling. In this model, the bridge structural components are expressed with component description, parametric description and geometric description in a software system. This model provides both convenience and flexibility for users in structural modeling process. The object-oriented method is applied in the model implementation. A bridge analysis preprocessor is developed on the basis of this model. It provides an effective way for bridge modeling. 展开更多
关键词 engineering-oriented modeling Parametric CAD Bridge structural analysis preprocess Structural modeling finite element method Structural analysis
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基于Pasternak地基模型的H(t)-T受荷桩受力变形分析
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作者 江杰 陈丽君 +3 位作者 柴文成 艾永林 欧孝夺 龚健 《上海交通大学学报》 北大核心 2025年第1期60-69,共10页
水平动荷载H(t)与扭矩T联合作用下的桩基受力变形较为复杂.为了更加准确地分析H(t)-T联合受荷桩的内力与位移,基于Pasternak地基模型考虑桩侧土体剪切效应;引入H(t)-T耦合因子,揭示多向荷载对桩身响应的影响机理;继而利用虚功原理推导... 水平动荷载H(t)与扭矩T联合作用下的桩基受力变形较为复杂.为了更加准确地分析H(t)-T联合受荷桩的内力与位移,基于Pasternak地基模型考虑桩侧土体剪切效应;引入H(t)-T耦合因子,揭示多向荷载对桩身响应的影响机理;继而利用虚功原理推导桩身单元综合刚度矩阵;最后采用改进的有限杆单元法获得H(t)-T联合受荷桩内力与位移数值解;并与已有理论解和有限元模拟结果进行对比验证.参数分析表明:土体剪切效应可约束桩身水平位移,但对扭转变形影响较小;水平动荷载增强了桩身抗扭承载力,水平动荷载幅值从0.2Q_(u)增大到1.0Q_(u)时,桩顶扭转角减小了22.6%;增大动荷载无量纲频率会减小桩顶位移和桩身最大弯矩,外荷载动力效应随桩埋深增加而减弱;杆单元模型减少了单元划分数量和计算时间,可有效提高计算效率. 展开更多
关键词 Pasternak地基模型 联合受荷桩 有限单元法 水平动荷载 扭矩
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基于超对偶数微分的无约束应力更新算法
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作者 路德春 石安毓 +1 位作者 周鑫 杜修力 《岩土工程学报》 北大核心 2025年第6期1113-1122,共10页
加卸载判断和繁琐的解析求导运算一直是制约先进弹塑性模型数值应用的瓶颈问题。研究提出一种基于超对偶数微分方法的无约束应力隐式更新算法,有效解决了上述计算难点。针对加卸载判断问题,新算法利用光滑函数代替弹塑性本构方程组中的K... 加卸载判断和繁琐的解析求导运算一直是制约先进弹塑性模型数值应用的瓶颈问题。研究提出一种基于超对偶数微分方法的无约束应力隐式更新算法,有效解决了上述计算难点。针对加卸载判断问题,新算法利用光滑函数代替弹塑性本构方程组中的Karush-Kuhn-Tucker条件,将受不等式约束的非线性应力积分方程组问题,转化为无约束的最小化问题,计算时无需加卸载判断。针对导数计算问题,新算法利用超对偶数微分方法代替解析求导,获得光滑函数的1阶导数以及塑性势函数的1阶和2阶导数,用于构造非线性计算的迭代公式,以保证局部应力更新迭代和全局平衡迭代的二次收敛速度。数值算例表明,相较于其它数值微分方法,超对偶数微分方法不受截断误差和减法消去误差影响,计算结果等同于解析求导。最后,基于所提算法编写了光滑莫尔库仑塑性模型的UMAT子程序,并通过3个典型边值问题的数值分析,验证了算法的有效性和收敛性速度。 展开更多
关键词 应力更新算法 塑性模型 超对偶数数值微分 一致性切线刚度矩阵 有限元法
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细粒尾矿充填模袋固结规律的数值模拟
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作者 刘小文 吴泽铭 +1 位作者 何海松 王建 《南昌大学学报(工科版)》 2025年第1期56-62,共7页
用细粒尾矿充填模袋,其脱水、固结时间较长,脱水固结规律直接影响其筑坝的沉降变形以及稳定性。采用ABAQUS软件模拟在不同充灌浓度和充灌高度条件下,模袋体在固结过程中位移、孔隙水压力分布以及模袋张力的变化规律,并将模拟结果与试验... 用细粒尾矿充填模袋,其脱水、固结时间较长,脱水固结规律直接影响其筑坝的沉降变形以及稳定性。采用ABAQUS软件模拟在不同充灌浓度和充灌高度条件下,模袋体在固结过程中位移、孔隙水压力分布以及模袋张力的变化规律,并将模拟结果与试验进行对比,结果较吻合。同时通过建立大尺寸模袋体模型研究在实际工程中大模袋固结排水速率受尺寸变化的影响。结果表明:模袋体的整体变形和孔隙水压力均随模袋高度的增加而逐渐增大;而模袋的整体变形和孔隙水压力随充灌浓度的增大逐渐减小;对于工程中的大尺寸模袋,沉降量与孔隙水压力消散时间均随模袋高度的增加而增大,不同模袋高度下最终沉降率均在24%左右。 展开更多
关键词 细粒尾矿 模袋法 有限元分析 影响因素 大尺寸模型
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双边工字钢-混组合曲线梁桥收缩徐变效应研究
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作者 闫磊 邢俊鹏 +1 位作者 牛哲 刘金鑫 《桥梁建设》 北大核心 2025年第1期95-102,共8页
为了解收缩徐变对双边工字钢-混组合曲线梁桥受力性能的影响,以该类型某3×35 m曲线梁为背景,开展模型试验及有限元分析。按1∶5的缩尺比制作曲率半径92 m的2×7 m试验梁,先对承载自重+配重3个月的试验梁挠度、应力进行观测,再... 为了解收缩徐变对双边工字钢-混组合曲线梁桥受力性能的影响,以该类型某3×35 m曲线梁为背景,开展模型试验及有限元分析。按1∶5的缩尺比制作曲率半径92 m的2×7 m试验梁,先对承载自重+配重3个月的试验梁挠度、应力进行观测,再使该试验梁承受自重+配重+开裂荷载11个月(即14个月龄期)进行同等观测。采用有限元法对不同曲率半径下3×35 m曲线组合梁桥的钢主梁挠度、应力长期(10年)增长系数取值进行研究。结果表明:14个月龄期后,试验梁挠度增加,增量约为初始挠度的10%,曲线内、外侧钢主梁挠度差可忽略不计;中支点处应力增加,距梁端0.4L(L为该跨跨径)处应力减少。当3×35 m曲线梁桥的曲率半径由460 m增加至1000 m时,对于挠度长期增长系数,中跨跨中处曲线内侧钢主梁由0.35线性变化至0.06、曲线外侧钢主梁由-1.13线性变化至-0.18,边跨距梁端0.4L处曲线内、外侧钢主梁不变,均取1.1;对于应力长期增长系数,中跨跨中处曲线内侧钢主梁由-0.44线性变化至-0.36、曲线外侧钢主梁由-0.27线性变化至-0.34,边跨距梁端0.4L处曲线内、外侧钢主梁不变,分别取0.89、0.90,中支点处的曲线内、外侧钢主梁不变,分别取1.35、1.30。 展开更多
关键词 钢-混组合梁桥 曲线梁桥 收缩徐变 应力 挠度 曲率半径 缩尺模型试验 有限元法
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变截面连续波形钢腹板-平钢底板组合梁桥应力偏载系数研究
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作者 陈宏彬 黄光铃 +2 位作者 陈宜言 解冰 赵秋 《世界桥梁》 北大核心 2025年第2期111-118,共8页
为了解波形钢腹板-平钢底板组合梁在偏载作用下的扭转畸变效应,对其应力偏载系数进行研究。对1片按相似比1∶5缩尺的三跨变截面连续波形钢腹板-平钢底板组合梁进行静力模型试验和有限元分析,计算其在偏载作用下的顶(底)板翘曲正应力、... 为了解波形钢腹板-平钢底板组合梁在偏载作用下的扭转畸变效应,对其应力偏载系数进行研究。对1片按相似比1∶5缩尺的三跨变截面连续波形钢腹板-平钢底板组合梁进行静力模型试验和有限元分析,计算其在偏载作用下的顶(底)板翘曲正应力、腹板扭转剪应力以及正应力偏载系数和腹板剪应力偏载系数,并与现有偏载系数计算方法的计算结果进行对比。结果表明:钢底板翘曲正应力相对混凝土顶板更加明显,腹板剪应力沿截面高度变化较小,中跨跨中设置横隔板能有效限制组合梁的畸变变形;取偏载系数试验值与有限元值中的大者作为偏载系数建议值,建议中支点负弯矩区截面、跨中截面和1/4跨截面正应力偏载系数分别不小于1.18、1.11和1.15,中支点负弯矩区截面、跨中截面和1/4跨截面腹板剪应力偏载系数分别不小于1.66、1.35和1.43;经验系数法对正应力偏载系数比较适用,对剪应力偏载系数不适用,偏心压力法计算过于保守,实际设计应用并不经济,修正偏心压力法对正应力与剪应力偏载系数均考虑不足。 展开更多
关键词 波形钢腹板-平钢底板组合梁 应力 应力偏载系数 模型试验 有限元法
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半潜式网箱系泊系统数值计算研究
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作者 吴皓 周松 +2 位作者 刘强 王凯 严俊 《船舶力学》 北大核心 2025年第2期200-208,共9页
随着水产养殖装备从近海逐步走向深远海,全养殖水体约9万方的半潜柱稳式网箱“深蓝2号”应运而生。为研究其在定常风流及不规则波作用下的水动力性能与运动响应特点,结合WADAM、SIMO及RIFLEX求解器建立适用于网箱时域分析的数值模型。... 随着水产养殖装备从近海逐步走向深远海,全养殖水体约9万方的半潜柱稳式网箱“深蓝2号”应运而生。为研究其在定常风流及不规则波作用下的水动力性能与运动响应特点,结合WADAM、SIMO及RIFLEX求解器建立适用于网箱时域分析的数值模型。数值模型由“深蓝2号”主体结构的水动力模型、内外双层网衣及系泊系统的有限元模型耦合而成。通过面元模型和莫里森模型相结合的方式求解网箱水动力,采用有限元法对网衣及系泊系统进行时域分析,其中网衣波流载荷的计算基于Screen模型。时域耦合分析发现网衣对网箱水动力性能作用显著,不可忽视。网箱有网衣作用的最大系泊张力约为无网衣的两倍,水平漂移范围亦更广。网箱的波浪二阶差频力对系泊张力及水平漂移影响比较小。研究结果对此类新型网箱水动力性能的评估及优化具有技术支撑及借鉴意义。 展开更多
关键词 “深蓝2号”网箱 面元模型 莫里森模型 Screen模型 有限元法
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艉轴密封装置Ω弹簧刚度计算及模型可信度分析
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作者 孙玮 申帅 +3 位作者 孙锋 曾良辉 叶晓明 曹海进 《舰船科学技术》 北大核心 2025年第9期114-119,共6页
艉轴密封装置用于出舱艉轴与舱壁之间的密封,是船舶推进系统的关键设备。Ω弹簧作为艉轴密封装置的重要部件,其应变特性将直接影响艉轴密封装置的密封性能。本文建立某型艉轴密封装置Ω弹簧结构强度数值模型,分别对外圈弹簧和内圈弹簧... 艉轴密封装置用于出舱艉轴与舱壁之间的密封,是船舶推进系统的关键设备。Ω弹簧作为艉轴密封装置的重要部件,其应变特性将直接影响艉轴密封装置的密封性能。本文建立某型艉轴密封装置Ω弹簧结构强度数值模型,分别对外圈弹簧和内圈弹簧进行有限元分析,获得不同压缩量下Ω弹簧的轴向力及最大应力值,并拟合得到Ω弹簧的刚度。在此基础上,开展了艉轴密封装置Ω弹簧应变测试。仿真结果与测试数据误差在5%以内,表明了本文所建数值模型的准确性。本文研究结果为艉轴密封装置设计与校核提供了重要参考。 展开更多
关键词 有限元法 结构强度 艉轴密封装置 可信度
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钢纤维混凝土冲击破坏特性GDEM软件模拟
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作者 张金 戚志刚 张磊 《应用数学和力学》 北大核心 2025年第5期621-632,共12页
钢纤维混凝土(steel fiber reinforced concrete, SFRC)是防护工程中最常用的结构材料,在爆炸、侵彻等强动载作用下,其往往处于高应变率的复杂应力状态.目前,关于SFRC的动态力学性能的研究大多局限于一维应力和一维应变加载条件下,而关... 钢纤维混凝土(steel fiber reinforced concrete, SFRC)是防护工程中最常用的结构材料,在爆炸、侵彻等强动载作用下,其往往处于高应变率的复杂应力状态.目前,关于SFRC的动态力学性能的研究大多局限于一维应力和一维应变加载条件下,而关于三向应力状态下的冲击压缩特性研究较少.该文采用基于连续-非连续介质力学的数值仿真软件GDEM-BlockDyna,模拟了围压对SFRC动态力学性能和破坏模式的影响.结果表明:围压下SFRC的峰值应力和峰值应变均随着应变率的提高有不同程度的增大,但围压会抑制SFRC冲击压缩强度的率效应.GDEM能较逼真地模拟应变率和围压对材料动态力学的影响,与有限元方法相比,GDEM能够更好地模拟SFRC从完整到破坏的过程及特征,且对SFRC峰值应力后的破坏阶段的描述模拟更加准确. 展开更多
关键词 钢纤维混凝土 主动围压 GDEM 有限元方法 HJC模型
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基于响应面方法的直升机机身有限元模型参数修正
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作者 朱尹 韩东 《南京航空航天大学学报(自然科学版)》 北大核心 2025年第2期252-258,共7页
为降低直升机机身的有限元模型与实际模型之间的偏差,采用了一种基于响应面法的直升机机身模型修正方法。该方法使用一个超曲面函数来近似地替代实际的、隐式的复杂函数关系,避免了传统参数修正方法每次迭代时都调用有限元程序的步骤。... 为降低直升机机身的有限元模型与实际模型之间的偏差,采用了一种基于响应面法的直升机机身模型修正方法。该方法使用一个超曲面函数来近似地替代实际的、隐式的复杂函数关系,避免了传统参数修正方法每次迭代时都调用有限元程序的步骤。同时,通过拉丁超立方采样减少样本点数量从而提高了计算效率。以直升机10%缩比机身模型为例,通过试验与有限元分析分别获得其实际模型与有限元模型的前六阶固有频率,通过灵敏度分析确定了设计参数,利用响应面方法对该机身模型进行了参数修正。机身的有限元模型预测结果与试验测试结果之间的固有频率平均误差由3.54%降低至1.03%,有限元模型的预测精度显著提升。修正结果表明,基于响应面方法的有限元模型修正方法能够有效地应用于直升机机身模型参数修正。 展开更多
关键词 直升机机身 模型修正 响应面方法 灵敏度分析 有限元分析 拉丁超立方采样
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织物增强橡胶基复合材料本构模型及其应用
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作者 孙戬 王彤 +3 位作者 陈云辉 林何 刘晖 成小乐 《纺织学报》 北大核心 2025年第1期95-102,共8页
为更准确地表征织物增强橡胶基复合材料在受力变形过程中的力学性能,针对二维编织物结构,基于连续介质力学将织物增强橡胶基复合材料应变能解耦为橡胶基体应变能、纤维拉伸应变能以及纤维之间相互作用引起的剪切应变能,结合橡胶、织物... 为更准确地表征织物增强橡胶基复合材料在受力变形过程中的力学性能,针对二维编织物结构,基于连续介质力学将织物增强橡胶基复合材料应变能解耦为橡胶基体应变能、纤维拉伸应变能以及纤维之间相互作用引起的剪切应变能,结合橡胶、织物增强复合材料的单轴拉伸及镜框剪切实验数据拟合得到本构模型参数。通过对织物增强密封带压缩仿真结果与实验数据进行比较,验证了所建立的舱门密封有限元模型的有效性,随后将织物增强橡胶基复合材料超弹性本构模型应用于飞机舱门压缩过程的模拟分析。结果表明:超弹性本构模型能够用于表征织物增强复合材料的各向异性非线性材料行为;经向/纬向纤维与密封带轴向呈0°角铺设方式的密封性能优于45°角铺设,舱门的密封性能与门框的加载量成正比关系。 展开更多
关键词 机织物 橡胶 织物增强复合材料 橡胶密封件 本构模型 舱门密封带 密封性 有限元法
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