高水頭弧形鋼閘門主框架強(qiáng)度及動(dòng)力穩(wěn)定性分析方法研究
發(fā)布時(shí)間：2019-05-15 21:59
【摘要】：弧形鋼閘門是水利水電工程樞紐的調(diào)節(jié)結(jié)構(gòu)和咽喉,隨著高壩大庫(kù)建設(shè)的發(fā)展,弧形鋼閘門向著高水頭方向發(fā)展,承受的總水壓力越來(lái)越大。對(duì)于高水頭弧形鋼閘門,主框架的薄壁主梁的梁高被設(shè)計(jì)的越來(lái)越大來(lái)承受高水頭水荷載,致使其跨高比越來(lái)越小,屬于分布荷載作用下發(fā)生橫力彎曲的深梁,從而使主框架成為深梁框架,結(jié)構(gòu)的空間效應(yīng)十分顯著。深梁框架的強(qiáng)度及動(dòng)力穩(wěn)定性問(wèn)題是高水頭弧形鋼閘門及許多鋼結(jié)構(gòu)工程設(shè)計(jì)中亟待研究和解決的重要課題,本文圍繞這兩個(gè)核心問(wèn)題展開研究,針對(duì)現(xiàn)有分析方法的不足之處,以提高計(jì)算精度和計(jì)算效率為目標(biāo),改進(jìn)深梁框架的強(qiáng)度及動(dòng)力穩(wěn)定性分析方法,使之能適應(yīng)高水頭弧形鋼閘門設(shè)計(jì)的需要,具體工作如下:(1)主框架薄壁深梁橫力彎曲強(qiáng)度分析方法研究主框架薄壁深梁橫力彎曲強(qiáng)度分析方法研究:::以高水頭弧形鋼閘門主框架的單軸對(duì)稱工字形截面薄壁深梁為研究對(duì)象,針對(duì)其橫力彎曲強(qiáng)度計(jì)算這一經(jīng)典力學(xué)問(wèn)題進(jìn)行系統(tǒng)研究,建立了薄壁深梁橫力彎曲的彎剪耦合力學(xué)模型,據(jù)此提出各應(yīng)力分量的理論計(jì)算公式;分析了不同支座約束、荷載分布、跨高比和截面特征時(shí)截面剪切變形對(duì)彎應(yīng)力的影響規(guī)律,揭示了薄壁深梁的彎剪耦合機(jī)理;提出了工字形截面梁臨界跨高比的計(jì)算公式,為細(xì)長(zhǎng)梁和深梁的劃分提供理論依據(jù)。通過(guò)數(shù)值算例驗(yàn)證了本文方法的精度并應(yīng)用該方法對(duì)某高水頭弧形鋼閘門的薄壁深梁進(jìn)行強(qiáng)度校核。本文提出的薄壁深梁橫力彎曲強(qiáng)度分析方法是對(duì)Timoshenko深梁理論的豐富和完善,可為薄壁深梁的強(qiáng)度分析和設(shè)計(jì)提供系統(tǒng)的理論分析方法,克服純彎曲理論分析結(jié)果的不安全性。(2)不考慮阻尼的主框架動(dòng)力穩(wěn)定性分析方法研究:提出應(yīng)用動(dòng)力剛度法對(duì)不考慮阻尼的框架結(jié)構(gòu)進(jìn)行動(dòng)力穩(wěn)定性分析,核心思想為:首先將復(fù)雜的結(jié)構(gòu)動(dòng)力穩(wěn)定性分析問(wèn)題(保守問(wèn)題)轉(zhuǎn)化為承受特定不變荷載的結(jié)構(gòu)的自由振動(dòng)分析問(wèn)題,降低求解難度;然后應(yīng)用動(dòng)力剛度法對(duì)受載結(jié)構(gòu)進(jìn)行自由振動(dòng)分析獲得固有振動(dòng)頻率;最后應(yīng)用受載結(jié)構(gòu)的固有振動(dòng)頻率確定動(dòng)力不穩(wěn)定區(qū)域。動(dòng)力剛度法是一種精確數(shù)值方法,對(duì)于框架結(jié)構(gòu),一個(gè)桿件離散為一個(gè)單元即可得到精確數(shù)值解,并且求解效率高,是分析不考慮阻尼的框架結(jié)構(gòu)動(dòng)力穩(wěn)定性的一種精確、高效的工程實(shí)用方法,克服以低階多項(xiàng)式作為形函數(shù)的有限元法求解精度差及求解效率低的問(wèn)題。通過(guò)數(shù)值算例驗(yàn)證了動(dòng)力剛度法的求解精度及求解效率。(3)考慮阻尼的主框架動(dòng)力穩(wěn)定性分析方法研究:提出精確有限元法對(duì)考慮阻尼的框架結(jié)構(gòu)進(jìn)行動(dòng)力穩(wěn)定性分析,核心思想為:提出應(yīng)用滿足桿件自由振動(dòng)微分方程的精確形函數(shù)作為有限元法的形函數(shù),應(yīng)用基于該精確形函數(shù)的有限元法(稱為精確有限元法)對(duì)框架結(jié)構(gòu)進(jìn)行動(dòng)力穩(wěn)定性分析,考慮阻尼對(duì)結(jié)構(gòu)動(dòng)力穩(wěn)定性的影響,形成結(jié)構(gòu)動(dòng)力穩(wěn)定性問(wèn)題的有限元方程;應(yīng)用基于弗洛凱理論的諧波平衡法獲得臨界頻率方程式,最終化為一個(gè)廣義特征值的求解問(wèn)題,進(jìn)而確定動(dòng)力不穩(wěn)定區(qū)域。精確有限元法是一種精確數(shù)值方法,對(duì)于框架結(jié)構(gòu),一個(gè)桿件離散為一個(gè)單元即可得到精確數(shù)值解,并且求解效率高,是分析框架結(jié)構(gòu)動(dòng)力穩(wěn)定性問(wèn)題(保守問(wèn)題和非保守問(wèn)題)的一種精確、高效的工程實(shí)用方法,克服以低階多項(xiàng)式作為形函數(shù)的有限元法求解精度差及求解效率低的問(wèn)題。通過(guò)數(shù)值算例驗(yàn)證了精確有限元法的求解精度及求解效率。(4)動(dòng)力剛度法及精確有限元法在框架結(jié)構(gòu)動(dòng)力穩(wěn)定分析中的應(yīng)用動(dòng)力剛度法及精確有限元法在框架結(jié)構(gòu)動(dòng)力穩(wěn)定分析中的應(yīng)用:①應(yīng)用動(dòng)力剛度法和精確有限元法分析了深梁的截面剪切變形及轉(zhuǎn)動(dòng)慣量、阻尼、靜力荷載因子α和動(dòng)力荷載因子β對(duì)框架結(jié)構(gòu)動(dòng)力穩(wěn)定性的影響規(guī)律。②對(duì)某高水頭弧形鋼閘門的動(dòng)力穩(wěn)定性問(wèn)題進(jìn)行了研究,建立了合理的空間框架簡(jiǎn)化模型;應(yīng)用動(dòng)力剛度法和精確有限元法分析了空間框架簡(jiǎn)化模型的動(dòng)力穩(wěn)定性,確定了動(dòng)力不穩(wěn)定區(qū)域;通過(guò)與模型試驗(yàn)相關(guān)數(shù)據(jù)的對(duì)比,判斷其是否發(fā)生參數(shù)共振,為閘門的安全運(yùn)行提供參考。③應(yīng)用動(dòng)力剛度法和精確有限元法探討了結(jié)構(gòu)的高階動(dòng)力不穩(wěn)定區(qū)域的求解規(guī)模問(wèn)題,進(jìn)一步說(shuō)明這兩種方法求解高階動(dòng)力不穩(wěn)定區(qū)域的優(yōu)勢(shì)。
[Abstract]:The arc-shaped steel gate is the regulating structure and the throat of the water conservancy and hydropower project hub. With the development of the construction of the large reservoir of the high dam, the arch-shaped steel gate is developed in the direction of high water head, and the total water pressure is increasing. for the high-head arc-shaped steel gate, the beam height of the thin-wall main beam of the main frame is more and more large to bear the high-head water load, so that the cross-span height ratio is smaller and smaller, The spatial effect of the structure is very significant. The strength and dynamic stability of the deep beam frame is an important subject to be studied and solved in the design of high-head arc-shaped steel gate and many steel structures. In order to improve the calculation accuracy and the calculation efficiency, the strength and the dynamic stability analysis method of the deep beam frame are improved, so that the method can adapt to the design requirements of the high-head arc-shaped steel gate, and the specific work is as follows: (1) The method for analyzing the transverse force bending strength of the thin-wall deep beam of the main frame is studied by the method of the method for analyzing the transverse force bending strength of the thin-wall deep beam of the main frame. Based on the study of the classical mechanics problem of the transverse force bending strength of the thin-wall deep beam, the mechanical model of the bending and shear coupling of the thin-wall deep beam is established, and the theoretical calculation formula for each stress component is proposed, and the constraint and load distribution of the different support are analyzed. The influence of the cross-section shear deformation on the bending stress in the cross-section and cross-section characteristics is regular, and the bending and shear coupling mechanism of the thin-wall deep beam is revealed. The calculation formula of the critical span height ratio of the I-shaped section beam is proposed, which provides a theoretical basis for the division of the elongated beam and the deep beam. The accuracy of this method is verified by a numerical example, and the strength of a thin-wall deep beam of a high-head arc-shaped steel gate is checked by using the method. The method of thin-wall deep beam transverse force bending strength is rich and perfect for Timoshenko deep beam theory, which can provide a theoretical analysis method for the strength analysis and design of thin-wall deep beam, and can overcome the unsafety of the analysis result of pure bending theory. (2) The dynamic stability analysis of the main frame with the damping is not considered: the dynamic stability analysis of the frame structure with no damping is proposed by applying the dynamic stiffness method, and the core idea is as follows: The method comprises the following steps of: firstly, converting a complex structural dynamic stability analysis problem (conservative problem) into a free vibration analysis problem of a structure which is subjected to a specific constant load, and reducing the solving difficulty; and then carrying out free vibration analysis on the loaded structure to obtain the natural vibration frequency by applying the dynamic stiffness method; Finally, the dynamic instability region is determined by the natural vibration frequency of the load-receiving structure. The dynamic stiffness method is an accurate numerical method. For the frame structure, a member can be discretized into a single unit to obtain the accurate numerical solution, and the solution efficiency is high. It is an accurate and efficient engineering practical method for analyzing the dynamic stability of the frame structure without considering the damping. The method for solving the problem of low accuracy and low solution efficiency is overcome by using the low-order polynomial as the shape function. The solution precision and efficiency of the dynamic stiffness method are verified by numerical examples. (3) The method of dynamic stability analysis of the main frame with damping is studied: the finite element method is proposed to analyze the dynamic stability of the frame structure with damping, and the core idea is that the exact shape function of the differential equation of the free vibration of the rod is put forward as the shape function of the finite element method, The finite element method (called the exact finite element method) based on the exact shape function is used to analyze the dynamic stability of the frame structure, and the influence of the damping on the dynamic stability of the structure is considered, and the finite element equation of the structural dynamic stability problem is formed. The critical frequency equation is obtained by the harmonic balance method based on the Floquet theory, and finally the problem of solving a generalized eigenvalue is solved, and the unstable region of the power is determined. The exact finite element method is an accurate numerical method. For the frame structure, a member can be discretized into a single unit to get the accurate numerical solution, and the solution efficiency is high. It is an accurate method for analyzing the dynamic stability of the frame structure (conservative and non-conservative problems). In order to solve the problem of low accuracy and low solution efficiency of the finite element method with the low-order polynomial as the shape function, a practical and practical method is proposed. The solution precision and efficiency of the accurate finite element method are verified by numerical examples. (4) The application of the dynamic stiffness method and the accurate finite element method to the dynamic stability analysis of the frame structure: The influence of shear deformation and moment of inertia, damping, static load factor and dynamic load factor on the dynamic stability of the frame structure is analyzed by the dynamic stiffness method and the exact finite element method. The dynamic stability of a high-head arc-shaped steel gate is studied, a reasonable space frame simplification model is established, the dynamic stability of the simplified model of the space frame is analyzed by using the dynamic stiffness method and the accurate finite element method, and the power unstable region is determined; By comparing the data with model test, it is judged whether the parameter resonance occurs, and provides a reference for the safe operation of the gate. By using the dynamic stiffness method and the exact finite element method, the scale problem of the high-order dynamic instability region of the structure is discussed, and the advantages of the two methods for solving the high-order dynamic instability region are further explained.
【學(xué)位授予單位】：西北農(nóng)林科技大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類號(hào)】：TV663.4;TV31
本文編號(hào)：2477796
[Abstract]:The arc-shaped steel gate is the regulating structure and the throat of the water conservancy and hydropower project hub. With the development of the construction of the large reservoir of the high dam, the arch-shaped steel gate is developed in the direction of high water head, and the total water pressure is increasing. for the high-head arc-shaped steel gate, the beam height of the thin-wall main beam of the main frame is more and more large to bear the high-head water load, so that the cross-span height ratio is smaller and smaller, The spatial effect of the structure is very significant. The strength and dynamic stability of the deep beam frame is an important subject to be studied and solved in the design of high-head arc-shaped steel gate and many steel structures. In order to improve the calculation accuracy and the calculation efficiency, the strength and the dynamic stability analysis method of the deep beam frame are improved, so that the method can adapt to the design requirements of the high-head arc-shaped steel gate, and the specific work is as follows: (1) The method for analyzing the transverse force bending strength of the thin-wall deep beam of the main frame is studied by the method of the method for analyzing the transverse force bending strength of the thin-wall deep beam of the main frame. Based on the study of the classical mechanics problem of the transverse force bending strength of the thin-wall deep beam, the mechanical model of the bending and shear coupling of the thin-wall deep beam is established, and the theoretical calculation formula for each stress component is proposed, and the constraint and load distribution of the different support are analyzed. The influence of the cross-section shear deformation on the bending stress in the cross-section and cross-section characteristics is regular, and the bending and shear coupling mechanism of the thin-wall deep beam is revealed. The calculation formula of the critical span height ratio of the I-shaped section beam is proposed, which provides a theoretical basis for the division of the elongated beam and the deep beam. The accuracy of this method is verified by a numerical example, and the strength of a thin-wall deep beam of a high-head arc-shaped steel gate is checked by using the method. The method of thin-wall deep beam transverse force bending strength is rich and perfect for Timoshenko deep beam theory, which can provide a theoretical analysis method for the strength analysis and design of thin-wall deep beam, and can overcome the unsafety of the analysis result of pure bending theory. (2) The dynamic stability analysis of the main frame with the damping is not considered: the dynamic stability analysis of the frame structure with no damping is proposed by applying the dynamic stiffness method, and the core idea is as follows: The method comprises the following steps of: firstly, converting a complex structural dynamic stability analysis problem (conservative problem) into a free vibration analysis problem of a structure which is subjected to a specific constant load, and reducing the solving difficulty; and then carrying out free vibration analysis on the loaded structure to obtain the natural vibration frequency by applying the dynamic stiffness method; Finally, the dynamic instability region is determined by the natural vibration frequency of the load-receiving structure. The dynamic stiffness method is an accurate numerical method. For the frame structure, a member can be discretized into a single unit to obtain the accurate numerical solution, and the solution efficiency is high. It is an accurate and efficient engineering practical method for analyzing the dynamic stability of the frame structure without considering the damping. The method for solving the problem of low accuracy and low solution efficiency is overcome by using the low-order polynomial as the shape function. The solution precision and efficiency of the dynamic stiffness method are verified by numerical examples. (3) The method of dynamic stability analysis of the main frame with damping is studied: the finite element method is proposed to analyze the dynamic stability of the frame structure with damping, and the core idea is that the exact shape function of the differential equation of the free vibration of the rod is put forward as the shape function of the finite element method, The finite element method (called the exact finite element method) based on the exact shape function is used to analyze the dynamic stability of the frame structure, and the influence of the damping on the dynamic stability of the structure is considered, and the finite element equation of the structural dynamic stability problem is formed. The critical frequency equation is obtained by the harmonic balance method based on the Floquet theory, and finally the problem of solving a generalized eigenvalue is solved, and the unstable region of the power is determined. The exact finite element method is an accurate numerical method. For the frame structure, a member can be discretized into a single unit to get the accurate numerical solution, and the solution efficiency is high. It is an accurate method for analyzing the dynamic stability of the frame structure (conservative and non-conservative problems). In order to solve the problem of low accuracy and low solution efficiency of the finite element method with the low-order polynomial as the shape function, a practical and practical method is proposed. The solution precision and efficiency of the accurate finite element method are verified by numerical examples. (4) The application of the dynamic stiffness method and the accurate finite element method to the dynamic stability analysis of the frame structure: The influence of shear deformation and moment of inertia, damping, static load factor and dynamic load factor on the dynamic stability of the frame structure is analyzed by the dynamic stiffness method and the exact finite element method. The dynamic stability of a high-head arc-shaped steel gate is studied, a reasonable space frame simplification model is established, the dynamic stability of the simplified model of the space frame is analyzed by using the dynamic stiffness method and the accurate finite element method, and the power unstable region is determined; By comparing the data with model test, it is judged whether the parameter resonance occurs, and provides a reference for the safe operation of the gate. By using the dynamic stiffness method and the exact finite element method, the scale problem of the high-order dynamic instability region of the structure is discussed, and the advantages of the two methods for solving the high-order dynamic instability region are further explained.
【學(xué)位授予單位】：西北農(nóng)林科技大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類號(hào)】：TV663.4;TV31
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