摘 要：鋼－聚氨酯復(fù)合管是一種新型的組合結(jié)構(gòu)構(gòu)件，它利用鋼管和聚氨酯兩種材料在受力過程中的相互作用，即鋼管對聚氨酯的套箍作用，使聚氨酯處于復(fù)雜應(yīng)力狀態(tài)之下，從而使聚氨酯的強(qiáng)度得以大幅度提高，塑性以及韌性得到顯著改善；同時，由于聚氨酯的存在，延緩或避免了鋼管過早的發(fā)生局部屈曲。兩種材料組合在一起，不僅使各自的特性達(dá)到充分發(fā)揮，同時組成的新的結(jié)構(gòu)體系也具有優(yōu)越的力學(xué)性能。鋼－聚氨酯結(jié)構(gòu)具有強(qiáng)度高、質(zhì)量輕、延性好、抗震強(qiáng)、耐疲勞、耐沖擊、施工簡單等優(yōu)越的力學(xué)性能，因而它在工程結(jié)構(gòu)中得到越來越廣泛的應(yīng)用。但是目前的理論研究大都偏重于鋼聚氨酯夾層結(jié)構(gòu)，對鋼－聚氨酯復(fù)合管這種新型組合結(jié)構(gòu)還未展開研究，因此，有必要對鋼－聚氨酯復(fù)合管的力學(xué)性能進(jìn)行研究。
本文以軸向荷載作用下的鋼－聚氨酯復(fù)合管為研究對象，通過試驗以及有限元模擬的方法，考察包括長細(xì)比、套箍系數(shù)等因素對其承載力的影響，為工程上廣泛使用這種結(jié)構(gòu)提供理論依據(jù)。首先通過試驗采集了各級荷載下試件的應(yīng)變、位移和極限承載力等實驗數(shù)據(jù)，以及在加載過程中的外形變化和破壞特征，并對試件的荷載－變形關(guān)系特點，以及長徑比和套箍系數(shù)對極限承載力的影響進(jìn)行了分析，其次建立了三維非線性有限元分析模型，對試件受力進(jìn)行了全過程分析，較為深入的揭示了鋼－聚氨酯復(fù)合管在軸向荷載作用下的工作機(jī)理。具體進(jìn)行了以下幾個方面的工作：
(1)測試采集了各級荷載下試件的應(yīng)變、位移和極限承載力等實驗數(shù)據(jù),，詳細(xì)記錄了鋼－聚氨酯復(fù)合管試件在加載過程中的外形變化和破壞特征。
(2)研究了鋼－聚氨酯復(fù)合管的荷載－變形關(guān)系曲線特點，總結(jié)出不同套箍系數(shù)、不同長徑比試件的荷載－變形曲線變化的規(guī)律以及整體工作全過程，分析了影響其承載力的因素。
(3)通過試驗數(shù)據(jù)建立鋼－聚氨酯復(fù)合管的三維非線性有限元分析模型，選取出適合的鋼管和聚氨酯彈性體的本構(gòu)關(guān)系模型。鋼管和聚氨酯彈性體采用ANSYS提供的等向彈塑性模型，使用Von Mises屈服準(zhǔn)則和相關(guān)流動法則來描述其塑性變形。在模型中，考慮到鋼管與聚氨酯之間的粘結(jié)性能良好，故采用雙單元模型，鋼管單元和聚氨酯單元之間共用節(jié)點。
(4)采用有限元法對鋼－聚氨酯復(fù)合管在軸向荷載作用下的受力進(jìn)行了全過程分析，分析了受力過程中鋼－聚氨酯復(fù)合管的破壞模態(tài)，較為深入的揭示了鋼－聚氨酯復(fù)合管在軸向荷載作用下的工作機(jī)理。
(5)通過試驗驗證有限元方法中采用的本構(gòu)關(guān)系模型是否恰當(dāng)，屈服準(zhǔn)則是否合理，聚氨酯和鋼管之間的粘結(jié)性能是否良好，并通過有限元和試驗結(jié)果提出鋼－聚氨酯復(fù)合管的承載能力簡化公式。

關(guān)鍵詞：鋼－聚氨酯復(fù)合管；非線性有限元；套箍系數(shù)；受力性能；試驗研究







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