本文選題：壓力鋼管 + 材料應(yīng)變硬化　； 參考：《廣西大學(xué)》2017年碩士論文

【摘要】：結(jié)構(gòu)極限承載力是水電站壓力鋼管強(qiáng)度設(shè)計(jì)和安全評(píng)估的重要指標(biāo),目前水電站壓力鋼管結(jié)構(gòu)極限承載力分析大多偏于安全地將材料簡(jiǎn)化為理想彈塑性材料,不考慮材料應(yīng)變硬化對(duì)極限承載力的影響。然而,材料應(yīng)變硬化對(duì)水電站壓力鋼管極限承載力有顯著的提高,為充分利用鋼材有必要考慮材料應(yīng)變硬化的影響�；诖�,本文在課題組以往研究成果基礎(chǔ)上,開(kāi)展了考慮材料應(yīng)變硬化的水電站壓力鋼管極限承載力分析方法研究,主要內(nèi)容包括:(1)結(jié)合理論分析和實(shí)驗(yàn)資料,擬合得到了壓力鋼管鋼材常用的雙線性、冪強(qiáng)化、Ramberg-Osgood和ASME本構(gòu)關(guān)系,并開(kāi)展了這四種本構(gòu)關(guān)系對(duì)壓力鋼管極限承載力和失效演化的影響規(guī)律研究。基于雙線性、冪強(qiáng)化、Ramberg-Osgood和ASME本構(gòu)模型的函數(shù)形式,采用試驗(yàn)數(shù)據(jù)擬合得到考慮材料應(yīng)變硬化的的四種本構(gòu)關(guān)系,擬合優(yōu)度分析表明各本構(gòu)關(guān)系均能良好反映壓力鋼管材料應(yīng)變硬化性能。研究表明,考慮材料應(yīng)變硬化的結(jié)構(gòu)極限承載力分析結(jié)果較不考慮可提高20%以上,前述四種硬化本構(gòu)關(guān)系對(duì)管道失效演化與極限承載力分析結(jié)果影響不大,極限承載力結(jié)果的差別在8%以?xún)?nèi)。(2)提出了基于等效理想彈塑性模型的壓力鋼管極限承載力分析方法�；趹�(yīng)變能守恒原則提出了等效屈服強(qiáng)度的兩種計(jì)算方法:根據(jù)全應(yīng)力-應(yīng)變曲線求解等效屈服強(qiáng)度;根據(jù)屈服強(qiáng)度與抗拉強(qiáng)度雙關(guān)鍵點(diǎn)數(shù)據(jù)求解等效屈服強(qiáng)度。研究表明,基于等效理想彈塑性模型的分析方法能便捷地評(píng)估管道結(jié)構(gòu)極限承載力,計(jì)算誤差在10%以?xún)?nèi)。(3)考慮材料應(yīng)變硬化,提出了壓力鋼管極限承載力分析的彈性模量縮減法(EMRM)。基于等效理想彈塑性模型,定義了考慮材料應(yīng)變硬化效應(yīng)的單元承載比,給出了動(dòng)態(tài)判別高承載單元的基準(zhǔn)承載比,利用變形能守恒原則確定高承載單元彈性模量縮減策略,進(jìn)而建立了考慮材料應(yīng)變硬化下結(jié)構(gòu)極限承載力分析的EMRM。為高效求解管道結(jié)構(gòu)極限承載力提供了新途徑。
[Abstract]:Structural ultimate bearing capacity is an important index for strength design and safety assessment of penstock in hydropower stations. At present, the analysis of ultimate bearing capacity of penstock structures of hydropower stations is mostly focused on safely simplifying the material to ideal elastic-plastic material. The effect of strain hardening on ultimate bearing capacity is not considered. However, the material strain hardening has a significant increase on the ultimate bearing capacity of the penstock in hydropower stations. In order to make full use of steel, it is necessary to consider the effect of material strain hardening. Based on the previous research results of the research group, this paper studies the ultimate bearing capacity analysis method of penstock in hydropower station considering material strain hardening, the main content of which includes theoretical analysis and experimental data. The bilinear, power-reinforced Ramberg-Osgood and ASME constitutive relations of steel tube are obtained by fitting. The influence of these four constitutive relations on ultimate bearing capacity and failure evolution of penstock is studied. Based on the function form of the bilinear, power-enhanced Ramberg-Osgood and ASME constitutive models, four constitutive relations considering strain hardening of materials are obtained by fitting the experimental data. The analysis of goodness of fit shows that each constitutive relation can well reflect the strain hardening property of steel tube material. The results show that the analysis results of ultimate bearing capacity of structures considering strain hardening of materials can be increased by more than 20%, and the above four kinds of hardening constitutive relations have little influence on the failure evolution and ultimate bearing capacity analysis results of pipelines. The difference of ultimate bearing capacity results is less than 8%.) an analysis method of ultimate bearing capacity of penstock based on equivalent ideal elastoplastic model is proposed. Based on the principle of conservation of strain energy, two calculation methods of equivalent yield strength are proposed: the equivalent yield strength is calculated according to the full stress-strain curve, and the equivalent yield strength is calculated according to the data of the two key points of yield strength and tensile strength. The results show that the analysis method based on the equivalent ideal elastoplastic model can be used to evaluate the ultimate bearing capacity of pipeline structure conveniently, and the calculation error is less than 10%. In this paper, the elastic modulus reduction method for ultimate bearing capacity analysis of penstock is presented. Based on the equivalent ideal elastic-plastic model, the load-bearing ratio of the element considering the strain hardening effect of the material is defined, the reference load ratio of the high-bearing element is dynamically distinguished, and the reduction strategy of the elastic modulus of the high-bearing element is determined by the principle of conservation of deformation energy. Furthermore, an EMRM is established to analyze the ultimate bearing capacity of structures under strain hardening. It provides a new way to solve the ultimate bearing capacity of pipeline structure efficiently.
【學(xué)位授予單位】：廣西大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類(lèi)號(hào)】：TV732.4

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 張偉;張陽(yáng);楊綠峰;;桁架結(jié)構(gòu)極限承載力分析的彈性模量縮減法[J];應(yīng)用基礎(chǔ)與工程科學(xué)學(xué)報(bào);2017年01期

2 張偉;郭杭\，

本文編號(hào)：1998628