轴向荷载作用下钢－聚氨酯复合管.doc
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轴向荷载作用下钢－聚氨酯复合管,摘 要：钢－聚氨酯复合管是一种新型的组合结构构件，它利用钢管和聚氨酯两种材料在受力过程中的相互作用，即钢管对聚氨酯的套箍作用，使聚氨酯处于复杂应力状态之下，从而使聚氨酯的强度得以大幅度提高，塑性以及韧性得到显著改善；同时，由于聚氨酯的存在，延缓或避免了钢管过早的发生局部屈曲。两种材料组合在一起，不仅使各自的特性达到充分...
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摘 要：钢－聚氨酯复合管是一种新型的组合结构构件，它利用钢管和聚氨酯两种材料在受力过程中的相互作用，即钢管对聚氨酯的套箍作用，使聚氨酯处于复杂应力状态之下，从而使聚氨酯的强度得以大幅度提高，塑性以及韧性得到显著改善；同时，由于聚氨酯的存在，延缓或避免了钢管过早的发生局部屈曲。两种材料组合在一起，不仅使各自的特性达到充分发挥，同时组成的新的结构体系也具有优越的力学性能。钢－聚氨酯结构具有强度高、质量轻、延性好、抗震强、耐疲劳、耐冲击、施工简单等优越的力学性能，因而它在工程结构中得到越来越广泛的应用。但是目前的理论研究大都偏重于钢聚氨酯夹层结构，对钢－聚氨酯复合管这种新型组合结构还未展开研究，因此，有必要对钢－聚氨酯复合管的力学性能进行研究。
本文以轴向荷载作用下的钢－聚氨酯复合管为研究对象，通过试验以及有限元模拟的方法，考察包括长细比、套箍系数等因素对其承载力的影响，为工程上广泛使用这种结构提供理论依据。首先通过试验采集了各级荷载下试件的应变、位移和极限承载力等实验数据，以及在加载过程中的外形变化和破坏特征，并对试件的荷载－变形关系特点，以及长径比和套箍系数对极限承载力的影响进行了分析，其次建立了三维非线性有限元分析模型，对试件受力进行了全过程分析，较为深入的揭示了钢－聚氨酯复合管在轴向荷载作用下的工作机理。具体进行了以下几个方面的工作：
(1)测试采集了各级荷载下试件的应变、位移和极限承载力等实验数据,，详细记录了钢－聚氨酯复合管试件在加载过程中的外形变化和破坏特征。
(2)研究了钢－聚氨酯复合管的荷载－变形关系曲线特点，总结出不同套箍系数、不同长径比试件的荷载－变形曲线变化的规律以及整体工作全过程，分析了影响其承载力的因素。
(3)通过试验数据建立钢－聚氨酯复合管的三维非线性有限元分析模型，选取出适合的钢管和聚氨酯弹性体的本构关系模型。钢管和聚氨酯弹性体采用ANSYS提供的等向弹塑性模型，使用Von Mises屈服准则和相关流动法则来描述其塑性变形。在模型中，考虑到钢管与聚氨酯之间的粘结性能良好，故采用双单元模型，钢管单元和聚氨酯单元之间共用节点。
(4)采用有限元法对钢－聚氨酯复合管在轴向荷载作用下的受力进行了全过程分析，分析了受力过程中钢－聚氨酯复合管的破坏模态，较为深入的揭示了钢－聚氨酯复合管在轴向荷载作用下的工作机理。
(5)通过试验验证有限元方法中采用的本构关系模型是否恰当，屈服准则是否合理，聚氨酯和钢管之间的粘结性能是否良好，并通过有限元和试验结果提出钢－聚氨酯复合管的承载能力简化公式。
关键词：钢－聚氨酯复合管；非线性有限元；套箍系数；受力性能；试验研究
Abstract：The main purpose of this paper is to research on the ultimate bearing capacity of polyurethane filled steel tube(PFST) under axial load. The polyurethane filled steel tube structures have a lot of advantages,such as high strength,light quantity, good anti-seismic performance ,good shape,fast strike , simple construction and so on, consequently, they have been used widely in the engineering practice in recent years.However, the current theory research mostly lay particular stress on steel sandwich structure of steel and polyurethane. Polyurethane filled steel tube has not been launched research. Therefore, it is very necessary to study the mechanical properties of polyurethane filled steel tube under axial load.
(1)This paper collects the test data on the stain deformation and ultimate bearing capacity,describe the change of figure and the failure patterns of the specimens.
(2)The influence of the different hoop coefficient and slenderness ratio of axial polyurethane filled steel tube on the load-deflection curve character and all the course of work are discussed.
(3)A 3-D nonlinear finite element model is established in the paper.The constitutive model of steel tube and polyurethane elastomers is selected. They are modeled by using plasticity modeled which is isotropic elasticity and plasticity model with a Von Mises yield surface.In the model, considering the adhesive property between the steel tube and polyurethane elastomers is good, the elements share their nodes.
(4)The finite element method is applied to the mechanic analysis in this paper on the former analysis.Mechanisms of polyurethane filled steel tube subjected axial loading conditions are analyzed based on the numerical method.
(5)Through verification test we know finite element method adopted in the constitutive relation model is appropriate, yield criterion is reasonable, and the adhesive property between polyurethane and steel tube are good.The simplified calculating formula for ultimate bearing capacity is presented by the regressive analysis.
Key words: PFST; nonlinear finite element; hoop coefficient;mechanical properties; experimental study
本文以轴向荷载作用下的钢－聚氨酯复合管为研究对象，通过试验以及有限元模拟的方法，考察包括长细比、套箍系数等因素对其承载力的影响，为工程上广泛使用这种结构提供理论依据。首先通过试验采集了各级荷载下试件的应变、位移和极限承载力等实验数据，以及在加载过程中的外形变化和破坏特征，并对试件的荷载－变形关系特点，以及长径比和套箍系数对极限承载力的影响进行了分析，其次建立了三维非线性有限元分析模型，对试件受力进行了全过程分析，较为深入的揭示了钢－聚氨酯复合管在轴向荷载作用下的工作机理。具体进行了以下几个方面的工作：
(1)测试采集了各级荷载下试件的应变、位移和极限承载力等实验数据,，详细记录了钢－聚氨酯复合管试件在加载过程中的外形变化和破坏特征。
(2)研究了钢－聚氨酯复合管的荷载－变形关系曲线特点，总结出不同套箍系数、不同长径比试件的荷载－变形曲线变化的规律以及整体工作全过程，分析了影响其承载力的因素。
(3)通过试验数据建立钢－聚氨酯复合管的三维非线性有限元分析模型，选取出适合的钢管和聚氨酯弹性体的本构关系模型。钢管和聚氨酯弹性体采用ANSYS提供的等向弹塑性模型，使用Von Mises屈服准则和相关流动法则来描述其塑性变形。在模型中，考虑到钢管与聚氨酯之间的粘结性能良好，故采用双单元模型，钢管单元和聚氨酯单元之间共用节点。
(4)采用有限元法对钢－聚氨酯复合管在轴向荷载作用下的受力进行了全过程分析，分析了受力过程中钢－聚氨酯复合管的破坏模态，较为深入的揭示了钢－聚氨酯复合管在轴向荷载作用下的工作机理。
(5)通过试验验证有限元方法中采用的本构关系模型是否恰当，屈服准则是否合理，聚氨酯和钢管之间的粘结性能是否良好，并通过有限元和试验结果提出钢－聚氨酯复合管的承载能力简化公式。
关键词：钢－聚氨酯复合管；非线性有限元；套箍系数；受力性能；试验研究
Abstract：The main purpose of this paper is to research on the ultimate bearing capacity of polyurethane filled steel tube(PFST) under axial load. The polyurethane filled steel tube structures have a lot of advantages,such as high strength,light quantity, good anti-seismic performance ,good shape,fast strike , simple construction and so on, consequently, they have been used widely in the engineering practice in recent years.However, the current theory research mostly lay particular stress on steel sandwich structure of steel and polyurethane. Polyurethane filled steel tube has not been launched research. Therefore, it is very necessary to study the mechanical properties of polyurethane filled steel tube under axial load.
(1)This paper collects the test data on the stain deformation and ultimate bearing capacity,describe the change of figure and the failure patterns of the specimens.
(2)The influence of the different hoop coefficient and slenderness ratio of axial polyurethane filled steel tube on the load-deflection curve character and all the course of work are discussed.
(3)A 3-D nonlinear finite element model is established in the paper.The constitutive model of steel tube and polyurethane elastomers is selected. They are modeled by using plasticity modeled which is isotropic elasticity and plasticity model with a Von Mises yield surface.In the model, considering the adhesive property between the steel tube and polyurethane elastomers is good, the elements share their nodes.
(4)The finite element method is applied to the mechanic analysis in this paper on the former analysis.Mechanisms of polyurethane filled steel tube subjected axial loading conditions are analyzed based on the numerical method.
(5)Through verification test we know finite element method adopted in the constitutive relation model is appropriate, yield criterion is reasonable, and the adhesive property between polyurethane and steel tube are good.The simplified calculating formula for ultimate bearing capacity is presented by the regressive analysis.
Key words: PFST; nonlinear finite element; hoop coefficient;mechanical properties; experimental study
