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A Stiffness Surface Method to Analyze the Cross-Sectional Mechanical Properties of Reinforced Thermoplastic Pipes Subjected to Axisymmetric Loads 被引量:3
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作者 LIU Wencheng WANG Shuqing 《Journal of Ocean University of China》 SCIE CAS CSCD 2021年第4期811-822,共12页
Axial and hoop stiffness can describe the elastic responses of reinforced thermoplastic pipes(RTPs)subjected to axisymmetric loads,such as tension,compression,pressure,and crushing loads.However,an accurate analytical... Axial and hoop stiffness can describe the elastic responses of reinforced thermoplastic pipes(RTPs)subjected to axisymmetric loads,such as tension,compression,pressure,and crushing loads.However,an accurate analytical prediction cannot be provided because of the anisotropy of RTP laminates.In the present study,a stiffness surface method,in which the analytical expressions of the axial and hoop stiffness are derived as two concise formulas,is proposed.The axial stiffness formula is obtained by solving the equilibrium equations of RTPs under a uniaxial stress state based on the homogenization assumption,whereas the hoop stiffness formula is derived from the combination of the elastic stability theory,the classical lamination theory,and NASA SP-8007 formula.To verify the proposed method,three types of RTPs are modeled to conduct the quasi-static analyses of the tension and crushing cases.The consistency between numerical and analytical results verifies the effectiveness of the proposed method on the prediction of the axial and hoop stiffness of RTPs,which also proves the existence of stiffness surfaces.As the axial stiffness is proportional to the radii,the axial stiffness surface consists of a series of straight lines,which can be used to predict both thin-walled and thick-walled RTPs.Meanwhile,the hoop stiffness is more applicable for thin-walled RTPs because the proposed method ignores the proportional relationship between the homogenized hoop elastic moduli and the reciprocal radii in helical structures. 展开更多
关键词 reinforced thermoplastic pipes(RTPs) helical fibers axial stiffness hoop stiffness
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Theoretical Prediction of the Bending Stiffness of Reinforced Thermoplastic Pipes Using a Homogenization Method 被引量:1
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作者 LIU Wencheng WANG Shuqing +1 位作者 BU Jiarun DING Xindong 《Journal of Ocean University of China》 SCIE CAS CSCD 2022年第6期1441-1453,共13页
The accurate prediction of bending stiffness is important to analyze the buckling and vibration behavior of reinforced thermoplastic pipes(RTPs)in practical ocean engineering.In this study,a theoretical method in whic... The accurate prediction of bending stiffness is important to analyze the buckling and vibration behavior of reinforced thermoplastic pipes(RTPs)in practical ocean engineering.In this study,a theoretical method in which the constitutive relationships between orthotropic and isotropic materials are unified under the global cylindrical coordinate system is proposed to predict the bending stiffness of RTPs.Then,the homogenization assumption is used to replace the multilayered cross-sections of RTPs with homogenized ones.Different from present studies,the pure bending case of homogenized RTPs is analyzed,considering homogenized RTPs as hollow cylindrical beams instead of using the stress functions proposed by Lekhnitskii.Therefore,the bending stiffness of RTPs can be determined by solving the homogenized axial elastic moduli and moment of inertia of cross sections.Compared with the existing theoretical method,the homogenization method is more practical,universal,and computationally stable.Meanwhile,the pure bending case of RTPs was simulated to verify the homogenization method via conducting ABAQUS Explicit quasi-static analyses.Compared with the numerical and existing theoretical methods,the homogenization method more accurately predicts the bending stiffness and stress field.The stress field of RTPs and the effect of winding angles are also discussed. 展开更多
关键词 reinforced thermoplastic pipes bending stiffness pure bending case homogenization assumption stress analysis
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An Application of the Modified Shear Lag Model to Study the Influence of Thermal Residual Stresses on the Stiffness and Yield Strength of Short Fiber Reinforced Metal Matrix Composites 被引量:1
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作者 Zhonghao JIANG and Jianshe LIAN(Dept. of Materials Science and Engineering, Jilin University of Technology, Changchun 130025, China)Shangli DONG and Dezhuang YANG(School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1999年第3期213-221,共9页
The modified shear lag model proposed recently was applied to calculate thermal residual stresses and subsequent stress distributions under tensile and compressive loadings. The expressions for the elastic moduli and ... The modified shear lag model proposed recently was applied to calculate thermal residual stresses and subsequent stress distributions under tensile and compressive loadings. The expressions for the elastic moduli and the yield strengths under tensile and compressive loadings were derived which take account of thermal residual stresses. The asymmetries in the elastic modulus and the yield strength were interpreted using the derived expressions and the obtained results of the stress calculations. The model predictions have exhibited good agreements with the experimental results and also with the other theoretical predictions 展开更多
关键词 ab Figure An Application of the Modified Shear Lag Model to Study the Influence of Thermal Residual Stresses on the stiffness and Yield Strength of Short Fiber reinforced Metal Matrix Composites
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A New Modification to Shear Lag Model as Applied to Stiffness and Yield Strength of Short Fiber Reinforced Metal Matrix Composites
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作者 Jiang, ZH Lian, JS +1 位作者 Yang, DZ Dong, SL 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1998年第6期516-522,共7页
A new modification for the shear lag model is given and the expressions for the stiffness and yield Strength of short fiber metal matri×composite are derived. These expressions are then compared with our experime... A new modification for the shear lag model is given and the expressions for the stiffness and yield Strength of short fiber metal matri×composite are derived. These expressions are then compared with our experimental data in a SiCw/Al-Li T6 composite and the published experimental data on different SiCw/Al T6 composites and also compared with the previous shear lag models and the other theoretical models. 展开更多
关键词 SiC A New Modification to Shear Lag Model as Applied to stiffness and Yield Strength of Short Fiber reinforced Metal Matrix Composites
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Experimental study and analysis on fatigue stiffness of RC beams strengthened with CFRP and steel plate 被引量:13
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作者 卢亦焱 胡玲 +1 位作者 李杉 王康昊 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第3期701-707,共7页
The objective of this work is to investigate the fatigue behavior of reinforced concrete(RC) beams strengthened with externally bonded carbon fiber reinforced polymer(CFRP) and steel plate. An experimental investigati... The objective of this work is to investigate the fatigue behavior of reinforced concrete(RC) beams strengthened with externally bonded carbon fiber reinforced polymer(CFRP) and steel plate. An experimental investigation and theoretical analysis were made on the law of deflection development and stiffness degradation, as well as the influence of fatigue load ranges. Test results indicate that the law of three-stage change under fatigue loading is followed by both midspan deflection and permanent deflection, which also have positive correlation with fatigue load amplitude. Fatigue stiffness of composite strengthened beams degrades gradually with the increasing of number of cycles. Based on the experimental results, a theoretical model by effective moment of inertia method is developed for calculating the sectional stiffness of such composite strengthened beams under fatigue loading, and the calculated results are in good agreement with the experimental results. 展开更多
关键词 carbon fiber reinforced polymer steel plate composite strengthening technique reinforced concrete beams fatigue stiffness
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Stiffness degradation-based damage model for RC members and structures using fiber-beam elements 被引量:2
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作者 Guo Zongming Zhang Yaoting +1 位作者 Lu Jiezhi Fan Jian 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2016年第4期697-714,共18页
To meet the demand for an accurate and highly efficient damage model with a distinct physical meaning for performance-based earthquake engineering applications, a stiffness degradation-based damage model for reinforce... To meet the demand for an accurate and highly efficient damage model with a distinct physical meaning for performance-based earthquake engineering applications, a stiffness degradation-based damage model for reinforced concrete (RC) members and structures was developed using fiber beam-column elements. In this model, damage indices for concrete and steel fibers were defined by the degradation of the initial reloading modulus and the low-cycle fatigue law. Then, section, member, story and structure damage was evaluated by the degradation of the sectional bending stiffness, rod-end bending stiffness, story lateral stiffness and structure lateral stiffness, respectively. The damage model was realized in Matlab by reading in the outputs of OpenSees. The application of the damage model to RC columns and a RC frame indicates that the damage model is capable of accurately predicting the magnitude, position, and evolutionary process of damage, and estimating stow damage more precisely than inter-story drift. Additionally, the damage model establishes a close connection between damage indices at various levels without introducing weighting coefficients or force-displacement relationships. The development of the model has perfected the damage assessment function of OpenSees, laying a solid foundation for damage estimation at various levels of a large-scale structure subjected to seismic loading. 展开更多
关键词 fiber beam-column element stiffness degradation damage index reinforced concrete column reinforced concrete frame
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Damage detection method in complicated beams with varying flexural stiffness
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作者 冯侃 励争 +1 位作者 高桂云 苏先樾 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2011年第4期469-478,共10页
A damage detection method for complicated beam-like structures is proposed based on the subsection strain energy method (SSEM), and its applicability condition is introduced. For a beam with the continuously varying... A damage detection method for complicated beam-like structures is proposed based on the subsection strain energy method (SSEM), and its applicability condition is introduced. For a beam with the continuously varying fiexural stiffness and an edge crack, the SSEM is used to detect the crack location effectively by numerical modal shapes. As a complicated beam, the glass fiber-reinforced composite model of a wind turbine blade is studied based on an experimental modal analysis. The SSEM is used to calculate the damage index from the measured modal parameters and locate the damage position in the blade model successfully. The results indicate that the SSEM based on the modal shapes can be used to detect the damages in complicated beams or beam-like structures for engineering applications. 展开更多
关键词 nondestructive testing modal strain energy varying flexural stiffness beam fiber reinforced composite material wind turbine blade
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Finite Element Calculation of the Flexural Stiffness of Corroded RC Eccentric Compressive Members
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作者 张华 卫军 +1 位作者 潘硚 黄滢 《Journal of Southwest Jiaotong University(English Edition)》 2010年第4期303-308,共6页
A finite element calculation model of corroded RC eccentric compressive members was build using finite element software ANSYS. The model considers the decline of mechanical properties and the effective section of a co... A finite element calculation model of corroded RC eccentric compressive members was build using finite element software ANSYS. The model considers the decline of mechanical properties and the effective section of a corroded steel bar,as well as the deterioration of bond character between corroded reinforcement and concrete. The reliability of the finite element model was evaluated by comparing the results of the finite element calculation with the data from experiments. Based on the finite element analysis results,the influence of corrosion degree,the diameter change of the longitudinal reinforcing bars and the spacing change of stirrups on the flexural stiffness were calculated and analyzed. 展开更多
关键词 reinforced concrete eccentric compressive members Flexural stiffness Finite element method Corrosion degree Diameter of longitudinal reinforcing bars Stirrup spacing
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Effect of Eccentric Shear Stiffness of Walls on Structural Response of RC Frame Buildings
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作者 Muhammad Umair Saleem 《Open Journal of Civil Engineering》 2017年第4期527-538,共12页
Current research study consists of determining the optimum location of the shear wall to get the maximum structural efficiency of a reinforced concrete frame building. It consists of a detailed analysis and design rev... Current research study consists of determining the optimum location of the shear wall to get the maximum structural efficiency of a reinforced concrete frame building. It consists of a detailed analysis and design review of a seven-story reinforced concrete building to understand the effect of shear wall location on the response of reinforced concrete structures when subjected to different earthquake forces. Three trail locations of shear walls are selected and their performance is monitored in terms of structural response under different lateral loads. Required objectives are achieved by obtaining design and construction drawings of an existing reinforced concrete structure and modeling it on Finite Element Method (FEM) based computer software. The structure is redesigned and discussed with four different configurations (one without shear wall and three with shear walls). Main framing components (Beams, Columns and Shear walls) of the superstructure are designed using SAP 2000 V. 19.0 whereas substructure (foundation) of RC building was?designed using SAFE. American Concrete Institute (ACI) design specifications were used to calculate the cracked section stiffness or non-linear geometrical properties of the cracked section. Uniform Building Code (UBC-97) procedures were adopted to calculate the lateral earthquake loading on the structures. Structural response of the building was monitored at each story level for each earthquake force zone described by the UBC-97. The earthquake lateral forces were considered in both X and Y direction of the building. Each configuration of shear wall is carefully analyzed and effect of its location is calibrated by the displacement response of the structure. Eccentricity to the lateral stiffness of the building is imparted by changing the location of shear walls. Results of the study have shown that the location of shear wall significantly affects the lateral response of the structure under earthquake forces. It also motivates to carefully decide the center of lateral stiffness of building prior to deciding the location of shear walls. 展开更多
关键词 reinforcED Concrete BUILDINGS COMPUTER aided Modelling SHEAR Walls stiff-ness Deformations
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锈蚀及疲劳损伤后钢筋混凝土梁寿命预测及敏感性分析 被引量:2
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作者 金伟良 余一凡 柏玉良 《东南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2024年第2期260-267,共8页
为了探究锈蚀和疲劳作用后钢筋混凝土梁的长期性能,基于试验建立了钢筋混凝土梁含初始损伤的长期性能计算模型.基于该模型建立了锈蚀及疲劳损伤后钢筋混凝土梁的极限状态方程,采用蒙特卡洛模拟研究了梁长期性能的时变可靠度并进行了寿... 为了探究锈蚀和疲劳作用后钢筋混凝土梁的长期性能,基于试验建立了钢筋混凝土梁含初始损伤的长期性能计算模型.基于该模型建立了锈蚀及疲劳损伤后钢筋混凝土梁的极限状态方程,采用蒙特卡洛模拟研究了梁长期性能的时变可靠度并进行了寿命预测,分析了设计参数和初始损伤对梁使用寿命的影响,研究了试验梁满足100 a使用寿命的临界服役条件.结果表明,锈蚀和疲劳作用会严重削弱钢筋混凝土梁的长期性能,仅含4%锈蚀率和15%疲劳损伤梁的长期性能难以满足服役要求.增加梁的截面高度和钢筋截面面积可以有效地提高梁的长期性能,增大梁的截面宽度只能改善初始损伤小的梁的长期性能. 展开更多
关键词 损伤钢筋混凝土梁 刚度计算模型 寿命预测 敏感性分析
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考虑节点刚度随机性的焊接钢筋部品变形计算方法研究 被引量:1
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作者 郑和晖 沈惠军 +1 位作者 厉勇辉 张峰 《桥梁建设》 EI CSCD 北大核心 2024年第1期125-132,共8页
为量化钢筋部品刚度,从受力机理角度出发,基于试验和理论分析,提出考虑刚度随机性的焊接钢筋部品变形计算方法。从受力机理的角度提出三向转动刚度独立力学求解模型,考虑钢筋直径的影响,设计了105组T形焊接钢筋试件及两类加载固定试验装... 为量化钢筋部品刚度,从受力机理角度出发,基于试验和理论分析,提出考虑刚度随机性的焊接钢筋部品变形计算方法。从受力机理的角度提出三向转动刚度独立力学求解模型,考虑钢筋直径的影响,设计了105组T形焊接钢筋试件及两类加载固定试验装置,开展分级加载试验;在此基础上,考虑焊接节点转动刚度随机性,提出基于蒙特卡洛随机抽样的焊接钢筋部品变形计算方法,并分别开展了6个焊接钢筋网片和6个钢筋块体试验进行验证。结果表明:钢筋焊接节点刚度与钢筋直径有关,当焊接条件相同时,钢筋直径越大,焊接节点刚度越大;同一钢筋直径组合的焊接节点转动刚度基本符合正态分布,3个方向的转动刚度R x>R z>R y;钢筋焊接节点刚度与焊接节点断面面积基本呈线性关系;竖筋和横筋连接节点刚度对钢筋部品变形影响显著,所采用的节点刚度取值方法计算的焊接钢筋部品变形偏差均在10%以内,与传统刚接和铰接方法相比,变形计算精度大幅提高,变形计算方法合理。 展开更多
关键词 桥梁工程 钢筋部品 焊接 节点刚度 随机性 变形 加载试验 计算方法
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考虑结构空间作用的RC框架梁轴向约束刚度研究
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作者 季静 黄芷若 +4 位作者 丁迅 杨坚 林鹏 郑振光 韩小雷 《建筑结构》 北大核心 2024年第20期112-120,111,共10页
为真实反映结构对框架梁的空间约束作用,提出了轴向约束刚度指标以量化结构空间约束,并建立可模拟框架结构空间约束作用的数值模型。对比足尺框架结构试验数据表明,按规范计算的框架梁抗弯承载力与试验值相对误差为42%~75%,考虑结构轴... 为真实反映结构对框架梁的空间约束作用,提出了轴向约束刚度指标以量化结构空间约束,并建立可模拟框架结构空间约束作用的数值模型。对比足尺框架结构试验数据表明,按规范计算的框架梁抗弯承载力与试验值相对误差为42%~75%,考虑结构轴向约束作用后相对误差缩小至25%以内,说明该模型可较好地模拟框架结构轴向约束作用,验证了该数值模型的合理性和可靠性。在有限元软件SAP2000中建立等效弹性数值模型,通过单参数分析得到对RC框架梁轴向约束刚度有显著影响的关键变量。在常见工程的取值范围内对关键变量进行充分的排列组合,开展规模化数值分析并总结结构空间约束的作用机理与RC框架梁极限状态下轴向约束刚度分布规律,得出了极限状态下RC框架梁轴向约束刚度的计算方法。 展开更多
关键词 钢筋混凝土框架结构 结构空间作用 轴向约束刚度 规模化数值分析 分布规律 回归分析
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薄壁型钢混凝土梁抗弯性能试验研究
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作者 任重 张志鹏 +2 位作者 何逸鸣 程亮 戴柳丝 《建筑钢结构进展》 CSCD 北大核心 2024年第8期19-27,39,共10页
为研究薄壁型钢混凝土(thin-walled steel reinforced concrete,TSRC)梁试件的抗弯性能,设计制作了5根TSRC梁并进行四点弯曲试验,探究不同抗剪螺杆布置方式、截面形式、剪跨比以及混凝土保护层厚度对TSRC梁试件抗弯性能的影响。研究结... 为研究薄壁型钢混凝土(thin-walled steel reinforced concrete,TSRC)梁试件的抗弯性能,设计制作了5根TSRC梁并进行四点弯曲试验,探究不同抗剪螺杆布置方式、截面形式、剪跨比以及混凝土保护层厚度对TSRC梁试件抗弯性能的影响。研究结果表明:TSRC梁的失效模式为薄壁钢管加载点处发生局部屈曲,外围混凝土保护层出现贯通斜裂缝,混凝土保护层沿抗剪螺杆开裂;TSRC梁试件在加载过程中未发生脆性破坏,表现出较好的延性;TSRC梁开裂荷载较小,在0.11P_(u)~0.15P_(u)之间,裂缝总数较少,稳定在6~10条;满跨布置螺杆、增大钢管截面尺寸、减小剪跨比以及增加保护层厚度均可提高TSRC梁试件的承载力。基于试验结果,建立适用于TSRC梁的极限抗弯承载力和抗弯刚度计算公式,可为该构件在实际工程中的应用提供参考。 展开更多
关键词 薄壁型钢混凝土 试验研究 抗弯性能 抗弯刚度
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内置型钢的圆形不锈钢管混凝土构件的抗弯性能
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作者 王志滨 张铋晗 +1 位作者 林万福 柯丞樑 《建筑钢结构进展》 CSCD 北大核心 2024年第8期11-18,共8页
采用有限元模型研究内置型钢的圆形不锈钢管混凝土构件的纯弯力学性能,有限元计算结果与试验结果吻合良好。该类典型构件的抗弯承载力比不锈钢管混凝土对比构件的相应值高111.33%;混凝土承担的弯矩也比对比构件的相应值高23.31%,受压区... 采用有限元模型研究内置型钢的圆形不锈钢管混凝土构件的纯弯力学性能,有限元计算结果与试验结果吻合良好。该类典型构件的抗弯承载力比不锈钢管混凝土对比构件的相应值高111.33%;混凝土承担的弯矩也比对比构件的相应值高23.31%,受压区混凝土的抗压承载力约提高了20%,原因是钢管和型钢翼缘对受压区混凝土形成了良好的约束作用。该类构件的抗弯刚度与抗弯承载力随着混凝土强度、不锈钢含钢率、型钢含钢率和回转半径比的增大而提高;其抗弯承载力随着不锈钢屈服强度或型钢屈服强度的增大而提高。最终给出了该类构件的抗弯刚度和抗弯承载力的简化计算方法。 展开更多
关键词 内置型钢的圆形不锈钢管混凝土 有限元模型 抗弯承载力 抗弯刚度 简化模型
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钢-PVA混杂纤维增强水泥基复合材料永久模板叠合RC单向板短期刚度计算方法 被引量:2
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作者 王照耀 梁兴文 +2 位作者 翟天文 王莹 吴奎 《材料导报》 EI CAS CSCD 北大核心 2024年第3期122-130,共9页
钢-PVA混杂纤维增强水泥基复合材料(HFRCC)具有良好的受拉韧性和耐久性能,是永久模板的理想材料。首先探究了PVA纤维掺量对HFRCC工作性能和抗折强度的影响,随着PVA纤维掺量增加,HFRCC的工作性能显著减弱,抗折强度先增大再减小,最终选用... 钢-PVA混杂纤维增强水泥基复合材料(HFRCC)具有良好的受拉韧性和耐久性能,是永久模板的理想材料。首先探究了PVA纤维掺量对HFRCC工作性能和抗折强度的影响,随着PVA纤维掺量增加,HFRCC的工作性能显著减弱,抗折强度先增大再减小,最终选用含有1.5%钢纤维和0.25%PVA纤维的HFRCC来制作永久模板。随后对六个HFRCC永久模板叠合RC单向板和一个RC单向板进行了四点受弯试验,探究了HFRCC-RC界面处理方式和配筋率对叠合板受弯性能的影响。试验结果表明:抹平、等距凹槽和钢钉拉毛三种界面处理方式对叠合板受弯性能的影响可以忽略;HFRCC模板能够有效限制裂缝发展,减小裂缝宽度和间距,叠合板的开裂弯矩相比于普通混凝土板提高了20.1%~31.7%。分别采用刚度解析法和有效惯性矩法建立了HFRCC-RC叠合板短期刚度计算方法,两种方法均有较高的计算精度且离散性较小。 展开更多
关键词 钢-PVA混杂纤维增强水泥基复合材料 永久模板 短期刚度 刚度解析法 有效惯性矩法
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Fatigue behavior of basalt-aramid and basalt-carbon hybrid fiber reinforced polymer sheets 被引量:3
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作者 潘建伍 吴刚 袁希贵 《Journal of Southeast University(English Edition)》 EI CAS 2013年第1期84-87,共4页
In order to study the fatigue failure mode and fatigue life laws of basalt-aramid and basalt-carbon hybrid fiber reinforced polymer ( FRP ) sheets, fatigue experiments are carried out, considering two hybrid ratios ... In order to study the fatigue failure mode and fatigue life laws of basalt-aramid and basalt-carbon hybrid fiber reinforced polymer ( FRP ) sheets, fatigue experiments are carried out, considering two hybrid ratios of 1 : 1 and 2:1 under different stress levels from 0.6 to 0.95. The results show that fractures occur first in carbon fibers or aramid fibers for the specimens with hybrid ratio of 1: 1, namely B1A1 and B1C1, while a fracture occurs first in basalt fibers for the specimens with a hybrid ratio of 2: 1, namely B2A1 and B2C1. The fatigue lives of the hybrid FRP sheets increase with the improvement of the content of carbon fibers or aramid fibers, and the influence of the carbon fibers content improvement to fatigue life is more significant. The fatigue performance of B2A1 is relatively worse, while the fatigue performance of B1C1 and B2C1 is relatively better. Finally, a new fatigue stiffness degradation model with dual variables and double inflection points is presented, which is applicable to both hybrid and normal FRP sheets. 展开更多
关键词 hybrid fiber reinforced polymer sheet basalt-aramid basalt-carbon fatigue experiment stiffness degradation model
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筋土峰值拉拔力的影响因素研究
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作者 姚文杰 李明宝 +1 位作者 郑俊杰 郭亿辉 《森林工程》 北大核心 2024年第1期201-206,共6页
为解决加筋土结构中筋土界面间复杂效应问题,采用筋材的微单元受力平衡方法,考虑剪切刚度与位移的影响,推导筋土峰值拉拔力计算公式;预测筋材在所受拉力不超过其峰值拉拔力的情况下各个位置的拉力及位移;在最大峰值拉拔力的范围内分析... 为解决加筋土结构中筋土界面间复杂效应问题,采用筋材的微单元受力平衡方法,考虑剪切刚度与位移的影响,推导筋土峰值拉拔力计算公式;预测筋材在所受拉力不超过其峰值拉拔力的情况下各个位置的拉力及位移;在最大峰值拉拔力的范围内分析筋材有效加筋长度、剪切刚度对筋材位移的影响及其变化规律。结果表明,在峰值拉拔力一定的情况下,筋材的有效加筋长度与剪切刚度对峰值拉拔力的影响较为显著,而弹性模量对峰值拉拔力的影响较小,筋材位移随着筋材有效加筋长度、剪切刚度的增大而呈非线性减小。将采用筋土界面峰值拉拔力公式的计算结果与拉拔试验的试验结果进行对比分析,发现两者的最大峰值拉拔力相差不大,结果吻合较好。研究成果可以为加筋土工程提供一定的理论参考。 展开更多
关键词 筋土界面 峰值拉拔力 剪切刚度 有效加筋长度 弹性模量
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纵向压力和加固钢板对隧道力学性能影响的解析解
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作者 江学辉 颜建伟 +2 位作者 罗文俊 李佳宝 徐长节 《岩土力学》 EI CAS CSCD 北大核心 2024年第6期1623-1632,共10页
为快速准确地评估纵向压力和加固钢板对盾构隧道力学性能的影响,基于隧道衬砌接缝面建立考虑纵向压力、弯矩和加固钢板耦合作用下的应力平衡方程,推导出了隧道力学性能的解析解。通过与经典抗弯刚度理论和数值模拟的计算结果对比,验证... 为快速准确地评估纵向压力和加固钢板对盾构隧道力学性能的影响,基于隧道衬砌接缝面建立考虑纵向压力、弯矩和加固钢板耦合作用下的应力平衡方程,推导出了隧道力学性能的解析解。通过与经典抗弯刚度理论和数值模拟的计算结果对比,验证了该方法的可靠性。研究表明:隧道中性轴随纵向压力、加固钢板厚度和弹性模量增加而减小;隧道抗弯刚度随弯矩增大而减小(最大和最小隧道抗弯刚度与弯矩大小无关),与纵向压力呈S曲线正相关,与加固钢板厚度和弹性模量呈非线性正相关。有加固钢板的隧道抗弯刚度是无加固钢板的6.58倍;弯矩承载力与纵向压力、加固钢板厚度和弹性模量呈非线性正相关;衬砌接缝张开量与纵向压力、加固钢板厚度和弹性模量呈非线性反相关,与弯矩呈非线性正相关。该计算方法解析地诠释了纵向压力与加固钢板对盾构隧道力学性能的影响机制。 展开更多
关键词 隧道工程 解析解 纵向压力 加固钢板 抗弯刚度
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大型复合材料构件机器人铣边站位优化研究
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作者 王震 郑侃 +2 位作者 董松 孙连军 王涛 《航空制造技术》 CSCD 北大核心 2024年第18期91-99,共9页
针对大型复合材料构件机器人铣边站位选取不合理导致加工质量低下的问题,提出基于最优刚度的单机器人多工位铣边站位优化方法。通过机器人运动学正逆解求得机器人刚度,建立与机器人站位相关的刚度函数模型。对不同站位下的机器人铣边任... 针对大型复合材料构件机器人铣边站位选取不合理导致加工质量低下的问题,提出基于最优刚度的单机器人多工位铣边站位优化方法。通过机器人运动学正逆解求得机器人刚度,建立与机器人站位相关的刚度函数模型。对不同站位下的机器人铣边任务进行分配,并通过基于刚度的站位优化算法开展机器人铣边站位优化研究,获得机器人刚度最优的一组站位。机器人铣边试验验证了机器人铣边站位的优化效果。结果表明,相比优化前,基于最优刚度的站位优化可显著提升机器人铣边稳定性,使铣边加工表面粗糙度降低33%以上。 展开更多
关键词 机器人加工 站位优化 移动机器人 碳纤维增强基复合材料 大型构件 刚度性能
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往复压载下纤维增强混凝土力学行为退化及本构关系
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作者 刁静 赵雪飞 +1 位作者 吕圆芳 卢同平 《水电能源科学》 北大核心 2024年第9期98-101,共4页
为研究钢纤维混凝土在往复轴压荷载下的力学性能及其本构关系,开展单轴往复压缩试验,以不同纤维掺量和长径比为变量,探究钢纤维混凝土的力学行为退化及损伤演化规律。结果表明,与单调加载相比,往复加载作用下钢纤维混凝土试件强度有轻... 为研究钢纤维混凝土在往复轴压荷载下的力学性能及其本构关系,开展单轴往复压缩试验,以不同纤维掺量和长径比为变量,探究钢纤维混凝土的力学行为退化及损伤演化规律。结果表明,与单调加载相比,往复加载作用下钢纤维混凝土试件强度有轻微退化;混凝土塑性应变累积随钢纤维体积掺量的增加而大幅降低,弹性刚度退化率随之增大,但对纤维长径比的影响不显著;应力退化率随卸载应变呈先减小后增大的变化趋势;基于力学行为退化现象和纤维增强效应,建立了钢纤维混凝土往复轴压下混凝土损伤演化模型,与试验结果进行比较发现该模型与试验数据吻合较好。 展开更多
关键词 钢纤维混凝土 往复轴压 刚度退化 应力退化率 损伤本构关系
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