本文選題：不銹鋼 + 材料非線(xiàn)性��； 參考：《浙江大學(xué)》2014年博士論文

【摘要】：不銹鋼材料不銹耐蝕,外觀精美,具有良好的力學(xué)和工藝性能,是一種外觀及使用性能優(yōu)異的建筑材料,但其受力性能與普通碳素鋼存在顯著不同：應(yīng)力—應(yīng)變關(guān)系表現(xiàn)為典型非線(xiàn)性,無(wú)屈服平臺(tái),比例極限較低,應(yīng)變硬化性能顯著。目前國(guó)內(nèi)對(duì)不銹鋼結(jié)構(gòu)力學(xué)性能方面的研究相對(duì)較少,又無(wú)相關(guān)設(shè)計(jì)標(biāo)準(zhǔn),極大地限制了不銹鋼材料在建筑結(jié)構(gòu)中的應(yīng)用與發(fā)展。本文對(duì)薄壁不銹鋼軸壓構(gòu)件的極限承載力進(jìn)行了深入研究。 首先對(duì)國(guó)內(nèi)外不銹鋼應(yīng)力—應(yīng)變關(guān)系模型的研究成果進(jìn)行梳理,通過(guò)介紹、分析、比較和驗(yàn)證,篩選最佳不銹鋼材料應(yīng)力—應(yīng)變關(guān)系模型。結(jié)果表明Quach提出的三段式模型具有較高精度且可采用Ramberg-Osgood三參數(shù)表示,是目前可供選用的最佳模型。 然后針對(duì)不銹鋼材料,利用廣義梁理論基本原理,推導(dǎo)出適用于非線(xiàn)性材料的修正廣義梁理論平衡方程,提出不銹鋼薄板受壓局部屈曲、卷邊槽形截面柱畸變屈曲及箱形截面柱彎曲屈曲荷載計(jì)算公式。結(jié)果表明其計(jì)算值與既有試驗(yàn)結(jié)果吻合良好,具有較高精度,可用于不銹鋼薄板受壓局部屈曲荷載、卷邊槽形截面柱畸變屈曲荷載及箱形截面柱彎曲屈曲荷載的確定。 接下來(lái)基于既有試驗(yàn)結(jié)果建立有限元分析模型,對(duì)四邊簡(jiǎn)支不銹鋼薄板均勻受壓的局部穩(wěn)定性能進(jìn)行研究,結(jié)合大量參數(shù)分析對(duì)Winter穩(wěn)定曲線(xiàn)進(jìn)行修正,提出適用于不銹鋼材料的薄板均勻受壓極限承載力和箱形截面構(gòu)件局部屈曲承載力計(jì)算公式。 之后對(duì)薄壁不銹鋼圓管柱軸心受壓性能進(jìn)行試驗(yàn)研究,包括標(biāo)準(zhǔn)材料拉伸試驗(yàn)、短柱軸向受壓試驗(yàn)和長(zhǎng)柱軸向受壓試驗(yàn),并基于試驗(yàn)結(jié)果對(duì)材料性能、破壞形態(tài)、位移、應(yīng)力分布和初始缺陷等進(jìn)行分析。 接著利用有限元軟件對(duì)上述試驗(yàn)進(jìn)行數(shù)值模擬,建立精確的有限元模型,并通過(guò)大量參數(shù)分析考察包括長(zhǎng)細(xì)比、壁厚、直徑、徑厚比、初始缺陷、材料性能等因素對(duì)薄壁不銹鋼圓管柱軸心受壓極限承載能力的影響,提出臨界修正長(zhǎng)細(xì)比和容許徑厚比計(jì)算公式。 最后對(duì)薄壁不銹鋼圓管柱軸心受壓的屈曲性能進(jìn)行理論分析,并就幾種國(guó)外不銹鋼結(jié)構(gòu)設(shè)計(jì)規(guī)范中的軸壓構(gòu)件極限承載力計(jì)算方法進(jìn)行介紹,最終基于大量有限元分析結(jié)果提出薄壁不銹鋼圓管長(zhǎng)柱、短柱軸心受壓極限承載力計(jì)算方法。結(jié)果表明其計(jì)算值與有限元結(jié)果吻合良好,與國(guó)外規(guī)范計(jì)算方法相比具有較高精度且偏于安全,可用于薄壁不銹鋼圓管柱軸心受壓構(gòu)件極限承載力的確定。
[Abstract]:Stainless steel is a kind of building material with excellent appearance and good mechanical and technological properties.However, the mechanical properties of the steel are obviously different from those of common carbon steel. The stress-strain relationship is typical nonlinear, has no yield platform, has low ratio limit, and has remarkable strain-hardening properties.At present, there are few researches on the mechanical properties of stainless steel structures in China, and there is no related design standard, which greatly limits the application and development of stainless steel materials in building structures.In this paper, the ultimate bearing capacity of thin-walled stainless steel members under axial compression is studied.Firstly, the research results of stress-strain relationship model of stainless steel at home and abroad are combed out, and the best stress-strain relationship model of stainless steel material is selected by introducing, analyzing, comparing and verifying.The results show that the three-segment model proposed by Quach has high accuracy and can be expressed by Ramberg-Osgood three parameters. It is the best model available at present.Then, based on the basic principle of generalized beam theory for stainless steel material, the modified generalized beam theory equilibrium equation suitable for nonlinear material is derived, and the local buckling of stainless steel thin plate under compression is proposed.The formulas for calculating buckling load of curved grooved column and box section column are presented.The results show that the calculated values are in good agreement with the experimental results and have high accuracy. It can be used to determine the local buckling load of stainless steel thin plate, the distorted buckling load of curved grooved column and the bending buckling load of box section column.Then the finite element analysis model is established based on the existing test results, and the local stability behavior of the thin stainless steel sheet with four edges simply supported under uniform compression is studied, and the stability curve of Winter is modified by a large number of parameter analysis.The formulas of uniform compressive ultimate bearing capacity and local buckling capacity of box section members suitable for stainless steel materials are presented.Then the axial compression performance of thin wall stainless steel round pipe string is studied, including the tensile test of standard material, the axial compression test of short column and the axial compression test of long column. Based on the test results, the properties of material, failure form and displacement are studied.Stress distribution and initial defects are analyzed.Then the finite element software is used to simulate the above experiments, and an accurate finite element model is established, and through a large number of parameter analysis, including the aspect ratio, wall thickness, diameter, diameter to thickness ratio, initial defect, etc.The influence of material properties on the ultimate bearing capacity of thin-walled stainless steel circular string under axial compression is discussed. The critical modified aspect ratio and the allowable diameter to thickness ratio are presented.Finally, the buckling behavior of thin-walled stainless steel circular tubular columns under axial compression is analyzed theoretically, and the calculation methods of ultimate bearing capacity of axial compression members in several foreign stainless steel structural design codes are introduced.Finally, based on a large number of finite element analysis results, the ultimate bearing capacity of thin-walled stainless steel tube columns under axial compression is proposed.The results show that the calculated values are in good agreement with the finite element results and have higher accuracy and safety than those of the foreign codes. It can be used to determine the ultimate bearing capacity of thin-walled stainless steel tubular columns under axial compression.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2014
【分類(lèi)號(hào)】：TU391

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