共查询到19条相似文献，搜索用时 250 毫秒
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FRP加固RC圆柱正截面受弯承载力计算（英文） 总被引：1，自引：0，他引：1
运用数值计算方法对FRP加固钢筋混凝土（RC）圆柱截面特性进行计算,发现截面破坏时受压区高度主要受轴压比、FRP约束强度比和纵筋配筋特征值3个主要参数影响.根据数值计算的结果进行回归,提出了受压区对应圆心角θ的计算方法.数值计算结果显示,横向约束导致的混凝土应力提高以及纵筋屈服后的强化效应使RC柱破坏时截面受弯承载力远大于规范规定值.根据理论分析和36个大比例试件实测结果提出截面破坏时受弯承载力计算方法,计算结果与试验结果吻合很好.最后,对一个典型柱变形能力进行参数分析,研究轴压比,纵筋配筋特征值和FRP约束强度比对正截面变弯承载力的影响.结果显示FRP加固圆柱破坏时受弯承载力可以比规范规定的未加固柱受弯承载力提高50%左右. 相似文献
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《浙江大学学报(A卷英文版)》2016,(6)
目的:压力管道是海洋石油化工等领域的常用构件,但经常受到泄漏、爆炸和冲击等事件的威胁。本文旨在探讨压力管道在高速冲击作用下的力学响应及失效机理。创新点:1.开发考虑金属大变形和高应变率的非线性模型,通过基于表面的流体腔模型来模拟管道气体和管道的耦合作用,简化计算模型,提高计算效率;2.通过非线性有限元模型,对管道高速冲击响应的影响因素进行研究分析。方法:1.采用Johnson-Cook模型模拟金属的大应变及大应变率;2.采用基于表面的流体腔模拟管道与内部气体的耦合作用;3.与实验结果对比验证模型的准确性;4.分析影响管道抗冲击性能的参数。结论:1.管道壁厚显著影响管道的抗冲击性能;2.在相同冲量下,冲击头与管道的接触面积越小,管道越容易被穿透;3.在管道受到冲击时,管道内压越大,管道抗穿透能力越小;4.在管道未被破坏时,管道内压能够增加管道的弹性,减小管道受冲击后的凹陷深度。 相似文献
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采用有限元软件AutoDyn,对TNT炸药起爆后爆炸冲击波遇到挡墙时的传播规律进行了三维数值模拟,分析了冲击波遇到挡墙时的反射高压及冲击波的环流汇聚作用。结果表明：冲击波遇到挡墙时将会产生反射高压;在比距离较小时,挡墙迎爆面的最大压力发生在挡墙底部;而随着比距离的增大,压力分布将沿挡墙高度趋于均匀。由于反射的作用,在挡墙前的地面上将会出现高压;当冲击波绕过挡墙时,在冲击波三个方向的绕射汇聚作用下,将会在墙后面一定区域内突然产生局部高压,并且随着传播的继续,这个区域不断的扩大,最后再次形成球面波传播。 相似文献
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为研究微小孔径气体受限冲击射流的换热特性,采用电阻丝加热方形酚醛树脂薄板作为模拟发热芯片的换热表面,沿对角线均匀布置热电偶以采集表面温度分布。以3mm孔径的圆形单孔及1mm孔径两种不同排列的圆形多孔喷射板对发热面进行中低Re数的射流冲击换热实验．通过改变风数及高度孔径比等参数得到了批数的径向分布及驻点区的换热特性,为射流冲击换热在封装芯片冷却上的应用提供了实验基础。 相似文献
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采用微元积分的思想,确定了球缺顶储油罐内油量与油位高度及横纵向倾斜角的函数关系模型,利用MATLAB软件编程对罐容表在不同变位角度下进行了标定,得出了在一定范围内任一组变位角度下储油罐的罐容表. 相似文献
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研究了由于储油罐发生纵向倾斜或横向偏转导致罐容表发生变化的问题.针对两端为平头,主体为椭圆柱的储油罐模型,利用割补法对没有变位的罐内液体体积进行精确求解;针对主体为圆柱,两端为球冠的储油罐模型,通过积分对储油量表达式进行了近似求解,进而确定罐内储油量与油位高度及变位参数之间的一般关系.通过实际数据进行拟合对所得结果进行检验,验证了模型的正确性与方法的可靠性.最后利用所得到结果,结合Matlab软件给出了储油罐的罐容表标定值,为非专业测量人员在实际工作中提供了测量依据. 相似文献
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《浙江大学学报(A卷英文版)》2016,(9)
目的:活性瓷釉涂层能够显著增强钢筋的防腐蚀能力,同时能够明显提升钢筋与混凝土的粘结力。通过对活性瓷釉涂层钢筋混凝土防护墙在冲击荷载作用下的破坏特征进行试验和数值模拟,为活性瓷釉涂层技术在钢筋混凝土结构中的应用提供理论基础。创新点:1.对活性瓷釉涂层钢筋混凝土防护墙进行爆炸荷载作用下的破坏试验;2.通过数值模拟,探究活性瓷釉钢纤维对钢筋混凝土结构抗爆能力的影响,为结构设计提出建议。方法1.通过对活性瓷釉涂层钢筋防护墙进行爆炸试验(图2),揭示活性瓷釉涂层钢筋混凝土结构的动力破坏特征(图4和5);2.通过数值方法研究活性瓷釉涂层对钢筋混凝土防护墙抗爆性能的影响,揭示在不同钢筋-混凝土粘结强度时钢筋混凝土结构整体性的变化规律(图10、13和15);3.在爆炸试验和数值分析基础上,提出活性瓷釉涂层钢筋混凝土结构抗爆设计建议(图16)。结论:1.活性瓷釉涂层能够显著改善钢筋在混凝土结构中的传力性能;在爆炸荷载作用下,涂层钢筋混凝土结构的破坏程度明显减轻。2.活性瓷釉涂层能够显著改善钢筋混凝土结构的变形特性,并显著增强其耗能能力。3.在采用活性瓷釉涂层进行抗爆设计时,采用直径较小的钢筋可提高结构的吸能能力。 相似文献
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软硬结构面的存在阻断了岩体性质的连续性,结构面倾角的位置和角度会造成多种破坏模式。文章对上软下硬地层隧道的破坏过程和破坏模式进行数值模拟研究。结果表明:分界结构面倾角在30°～75°时隧道稳定性较差;围岩变形破坏特征在对称模式下,围岩位移、破坏区和塑性区呈对称分布;在非对称模式下,结构面倾角和围岩的力学参数决定了破坏区的位置和范围,破坏区的位置主要受结构面倾角的影响。 相似文献
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讨论储油罐的变位识别及变位后罐容表的标定。为得出油罐变位后的液体容量,利用微积分的思想建立积分模型、并用实验数据建立插值模型,给出了完整的罐容表标定值,且通过误差分析,验证标定值的正确性。对于实际储油罐的实测数据,利用分层搜索法确定变位参数,并进行灵敏度分析,得出了纵向倾斜的灵敏度远大于横向偏转的结论。 相似文献
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In order to constitute engineering design methods of the flat ribbon wound explosion containment vessels, the dynamic response of such vessels subjected to internal explosion loading is simulated using LS-DYNA3D. Three winding angles, 10°, 15°and 20°, are considered. It is shown that among ribbon vessels investigated, the center displacement of outermost ribbons of the vessel with 10°winding angle is the smallest under the same blast loading. The response of vessels loaded in inner core is local. From the center of the cylindrical shell to the bottom cover, the maximum strain gradually decreases. The ribbons are subjected to tension in the length direction and compression in the width direction. Blasting shock energy concentrates on where is close to center section of blasting. For comparison, numerical simulation of a monobloc thick-walled explosion containment vessel is also investigated. It can be found that the biggest deformation of the flat ribbon wound explosion containment vessels is bigger than that of the monobloc thick-walled explosion containment vessel in the center section of blasting under the same TNT. Numerical results are approximately in agreement with experimental ones. It is proved that the ribbon vessels have the valuable properties of " leak before burst at worst" compared with the monobloc vessels through numerical simulation. 相似文献
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DEEKS Andrew 《天津大学学报(英文版)》2006,12(Z1)
To model the damage process of masonry walls under blast loading, a dynamic continuum damage material model is constructed for brick and mortar separately. The degradation of both the stiffness and strength are governed by a damage variable. By using the proposed material model, damage and fragmentation of a typical masonry wall under blast loading at different scaled distances is calculated. The hazard level of the masonry wall to blast loading is evaluated by analyzing the numerical results. 相似文献
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ZHOU Xiaoqing HAO Hong DEEKS Andrew 《天津大学学报(英文版)》2006,12(B09):132-137
To model the damage process of masonry walls under blast loading, a dynamic continuum damage material model is constructed for brick and mortar separately. The degradation of both the stiffness and strength are governed by a damage variable. By using the proposed material model, damage and fragmentation of a typical masonry wall under blast loading at different scaled distances is calculated. The hazard level of the masonry wall to blast loading is evaluated by analyzing the numerical results. 相似文献
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The explosion inside tunnel would generate blast wave which transmits through the longitudinal tunnel. Because of the close-in effects of the tunnel and the reflection by the confining tunnel structure, blast wave propagation inside tunnel is distinguished from that in air. When the explosion happens inside tunnel, the overpressure peak is higher than that of explosion happening in air. The continuance time of the blast wave also becomes longer. With the help of the numerical simulation finite element software LS-DYNA, a three-dimensional nonlinear dynamic simulation analysis for an explosion experiment inside tunnel was carried out. LS-DYNA is a fully integrated analysis program specifically designed for nonlinear dynamics and large strain problems. Compared with the experimental results, the simulation results have made the material parameters of numerical simulation model available. By using the model and the same material parameters, many results were adopted by calculating the model under different TNT explosion dynamites. Then the method of dimensional analysis was used for the simulation results. As overpressures of the explosion blast wave are the governing factor in the tunnel responses, a formula for the explosion blast wave over-pressure at a certain distance from the detonation center point inside the tunnel was derived by using the dimensional analysis theory. By comparing the results computed by the formula with experimental results which were obtained before, the formula was proved to be very applicable at some instance. The research may be helpful to estimate rapidly the effect of internal explosion of tunnel on the structure. 相似文献
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Surface contact explosion experiments have been performed for the study of dynamic response of the hard-soft-hard sandwich panel under blast loading. Experimental results have shown that there are four damage modes, including explosion cratering, scabbing of the backside, radial cracking induced failure and circumferential cracking induced failure. It also illustrates that the foam material sandwiched in the multi-layered media has an important effect on damage patterns. The phenomena encountered have been analyzed by the calculation with ALE method. Meanwhile, the optimal analysis of foam material thickness and position in the sandwich panel were performed in terms of experimental and numerical analysis. The proper thickness proportion of the soft layer is about 20% to the thickness of sandwich panel and the thickness of the upper hard layer and lower hard layer is in the ratio of 7 to 3 under the condition in this paper when the total thickness of soft layer remains constant. 相似文献
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In Order to reduce economic and life losses due to terrorism or accidental explosion threats,reinforced concrete(RC)slabs of buildings need to be designed or retrofitted to resist blast loading.In this paper the dynamic behavior Of RC slabs under blast loading and its influencing factors are studied.The numerical model of an RC slab subjected to blast loading is established using the explicit dynamic analysis software.Both the strain rate effect and the damage accumulation are taken into account in the material model.The dynamic responses of the RC slab subiected to blast loading are analyzed,and the influence of concrete strength,thickness and reinforcement ratio on the behavior of the RC slab under blast loading iS numerically investigated.Based on the numerical results.some principles for blast-resistant design and retrofitting are proposed to improve the behavior of the RC slab subjected to blast loading. 相似文献
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The progressive collapse of steel frame structures under the blast load was investigated using LS-DYNA.The multi-material Eulerian and Lagrangian coupling algorithm was adopted.A fluid-structure coupling finite element model was established which consists of Lagrange element for simulating steel frame structures and concrete ground,multiple ALE element for simulating air and TNT explosive material.Numerical simulations of the blast pressure wave propagation,structural dynamic responses and deformation,and progressive collapse of a five-story steel frame structure in the event of an explosion near above ground were performed.The numerical analysis showed that the Lagrangian and Eulerian coupling algorithm gave good simulations of the shock wave propagation in the mediums and blast load effects on the structure.The columns subjected to blast load may collapse by shear yielding rather than by flexural deformation.The columns and joints of steel beam to column in the front steel frame structure generated enormous plastic deformation subjected to intensive blast waves,and columns lost carrying capacity,subsequently leading to the collapse of the whole structure.The approach coupling influence between structural deformation and fluid load well simulated the progressive collapse process of structures,and provided an effective tool for analyzing the collapse mechanism of the steel frame structure under blast load. 相似文献
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Numerical Simulation of Dynamic Response and Collapse for Steel Frame Structures Subjected to Blast Load 总被引：4，自引：0，他引：4
The progressive collapse of steel frame structures under the blast load was investigated using LS-DYNA. The multi-material Eulerian and Lagrangian coupling algorithm was adopted. A flu-id-structure coupling finite element model was established which consists of Lagrange element for simulating steel frame structures and concrete ground, multiple ALE element for simulating air and TNT explosive material. Numerical simulations of the blast pressure wave propagation, struc-tural dynamic responses and deformation, and progressive collapse of a five-story steel frame structure in the event of an explosion near above ground were performed. The numerical analysis showed that the Lagrangian and Eulerian coupling algorithm gave good simulations of the shock wave propagation in the mediums and blast load effects on the structure. The columns subjected to blast load may collapse by shear yielding rather than by flexural deformation. The columns and joints of steel beam to column in the front steel frame structure generated enormous plastic defor-mation subjected to intensive blast waves, and columns lost carrying capacity, subsequently lead-ing to the collapse of the whole structure. The approach coupling influence between struc-tural deformation and fluid load well simulated the progressive collapse process of structures, and provided an effective tool for analyzing the collapse mechanism of the steel frame structure under blast load. 相似文献
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In the investigation of accidental explosion scene,the damage on the glass is one of the typical traces which can be used to decide the characteristic of the explosion source.To analyze the response of glass under the blast load,a numerical model was developed.In the model,the brittleness glass model was adopted.A 'node release' method,which had some special merits compared with the erosion method was used to simulate the rupture of the glass In the calculation,several problems which play major role in the response of the glass were discussed.The velocity and the displacement of the glass fragment were two major factors.The numerical results are very helpful for the design and hazard assessment. 相似文献