本文選題：張拉膜結(jié)構(gòu) + 氣彈模型試驗(yàn)��； 參考：《哈爾濱工業(yè)大學(xué)》2015年博士論文

【摘要】：膜結(jié)構(gòu)因其輕柔特性,在風(fēng)荷載作用下會(huì)產(chǎn)生較大的變形和振動(dòng),這種變形和振動(dòng)反過(guò)來(lái)又影響到結(jié)構(gòu)周圍的流場(chǎng),形成所謂的“流固耦合效應(yīng)”。特定條件下,流固耦合效應(yīng)會(huì)導(dǎo)致結(jié)構(gòu)振幅隨風(fēng)速增加急劇增大,產(chǎn)生類似橋梁和機(jī)翼的氣彈失穩(wěn)現(xiàn)象。由于氣彈失穩(wěn)對(duì)結(jié)構(gòu)抗風(fēng)安全威脅很大,因而對(duì)其作用機(jī)理的研究一直是結(jié)構(gòu)風(fēng)工程領(lǐng)域的重要課題之一。但這方面的工作以往多集中于橋梁結(jié)構(gòu),對(duì)膜結(jié)構(gòu)的研究很少。其中的一個(gè)重要原因在于,膜結(jié)構(gòu)的動(dòng)力特性十分復(fù)雜,難以像橋梁那樣簡(jiǎn)化為僅具有平動(dòng)和轉(zhuǎn)動(dòng)自由度的節(jié)段模型。近年來(lái),國(guó)內(nèi)外大型膜結(jié)構(gòu)在強(qiáng)風(fēng)作用下的破壞事件時(shí)有發(fā)生,說(shuō)明現(xiàn)階段的膜結(jié)構(gòu)抗風(fēng)設(shè)計(jì)理論還存在一定的不足,需要進(jìn)一步探索膜結(jié)構(gòu)的風(fēng)致動(dòng)力災(zāi)變的機(jī)理,探討氣彈失穩(wěn)發(fā)生的可能性及應(yīng)對(duì)措施�；谏鲜霰尘�,本文開展了系列膜結(jié)構(gòu)氣彈模型風(fēng)洞試驗(yàn)研究,通過(guò)對(duì)結(jié)構(gòu)多種響應(yīng)特征參數(shù)隨風(fēng)速變化規(guī)律的探討,明確了結(jié)構(gòu)與風(fēng)場(chǎng)間的相互作用機(jī)制,揭示了膜結(jié)構(gòu)的氣彈失穩(wěn)機(jī)理,建立了考慮氣彈失穩(wěn)的膜結(jié)構(gòu)抗風(fēng)設(shè)計(jì)方法。本文主要工作包括如下幾方面:1.建立了基于全荷載域和多響應(yīng)特征的膜結(jié)構(gòu)氣彈失穩(wěn)研究方法。鑒于膜結(jié)構(gòu)風(fēng)振響應(yīng)具有幾何非線性明顯和多階模態(tài)參振等特點(diǎn),傳統(tǒng)的結(jié)構(gòu)氣彈失穩(wěn)研究方法不再適用,需建立適用于多自由度柔性體系的氣彈失穩(wěn)研究方法。為此,提出了基于全荷載域和多響應(yīng)特征的膜結(jié)構(gòu)氣彈失穩(wěn)綜合研究方法。該方法是以氣彈模型風(fēng)洞試驗(yàn)為主,聯(lián)合運(yùn)用數(shù)值模擬和解析方法,從結(jié)構(gòu)響應(yīng)特征和流場(chǎng)變化規(guī)律兩方面入手,通過(guò)考察不同風(fēng)速(全荷載域)下結(jié)構(gòu)響應(yīng)與流場(chǎng)風(fēng)速之間的相關(guān)性,以及結(jié)構(gòu)振幅、主導(dǎo)振型和系統(tǒng)阻尼比等特征參數(shù)的變化規(guī)律,來(lái)揭示膜結(jié)構(gòu)的氣彈失穩(wěn)機(jī)理。在建立總體研究框架的基礎(chǔ)上,對(duì)若干關(guān)鍵技術(shù)問(wèn)題,如模態(tài)識(shí)別方法、阻尼識(shí)別方法和基于動(dòng)邊界技術(shù)的CFD數(shù)值模擬方法等進(jìn)行了探討,并驗(yàn)證了其有效性。2.設(shè)計(jì)并完成了系列典型膜結(jié)構(gòu)氣彈模型風(fēng)洞試驗(yàn)。氣彈模型風(fēng)洞試驗(yàn)一直是結(jié)構(gòu)風(fēng)工程領(lǐng)域的一個(gè)難題,尤其是膜結(jié)構(gòu)的氣彈模型風(fēng)洞試驗(yàn),如何選擇合適的模型材料以及如何避免測(cè)量裝置對(duì)風(fēng)場(chǎng)和結(jié)構(gòu)振動(dòng)的干擾,都是需要解決的關(guān)鍵問(wèn)題�；趯�(duì)氣彈模型相似理論、非接觸測(cè)量技術(shù)和預(yù)張力施加方法等問(wèn)題的探討,設(shè)計(jì)并完成了開敞式單向張拉膜結(jié)構(gòu)、封閉式單向張拉膜結(jié)構(gòu)和鞍形張拉膜結(jié)構(gòu)氣彈模型風(fēng)洞試驗(yàn),獲得了不同風(fēng)速下的結(jié)構(gòu)風(fēng)振響應(yīng)及其表面風(fēng)場(chǎng)變化數(shù)據(jù)。通過(guò)對(duì)結(jié)構(gòu)振幅和主導(dǎo)振型在不同風(fēng)速下的變化規(guī)律分析,發(fā)現(xiàn)存在振幅急劇增大和主導(dǎo)振型跳躍等現(xiàn)象,初步判斷該現(xiàn)象與結(jié)構(gòu)氣彈失穩(wěn)有關(guān)。3.聯(lián)合運(yùn)用多種研究手段,揭示了膜結(jié)構(gòu)的氣彈失穩(wěn)機(jī)理。通過(guò)對(duì)全荷載域下結(jié)構(gòu)的位移響應(yīng)和流場(chǎng)風(fēng)速相關(guān)性分析,確定發(fā)生氣彈失穩(wěn)的風(fēng)速區(qū)間;結(jié)合頻譜分析進(jìn)一步考察了結(jié)構(gòu)位移主導(dǎo)頻率與風(fēng)速主導(dǎo)頻率,發(fā)現(xiàn)氣彈失穩(wěn)時(shí)風(fēng)速主導(dǎo)頻率出現(xiàn)了類似渦激共振的鎖定現(xiàn)象。為驗(yàn)證該現(xiàn)象,分別開展了考慮結(jié)構(gòu)平均變形和受迫振動(dòng)的CFD數(shù)值模擬研究,發(fā)現(xiàn)隨著結(jié)構(gòu)平衡構(gòu)形的改變,結(jié)構(gòu)表面的漩渦脫落頻率也發(fā)生了變化,當(dāng)其與結(jié)構(gòu)某階自振頻率相接近時(shí),就會(huì)引發(fā)結(jié)構(gòu)的大幅振蕩,而這種大幅振蕩又反過(guò)來(lái)控制了漩渦脫落頻率,從而出現(xiàn)鎖定現(xiàn)象。此外,還分析了系統(tǒng)總阻尼比隨風(fēng)速的變化,發(fā)現(xiàn)其隨風(fēng)速增加呈現(xiàn)先增大后減小的特征,峰值點(diǎn)恰好對(duì)應(yīng)出現(xiàn)氣彈失穩(wěn)時(shí)的前一個(gè)風(fēng)速;該現(xiàn)象可解釋為由于氣動(dòng)阻尼作用導(dǎo)致結(jié)構(gòu)主導(dǎo)振型的阻尼比迅速增大,迫使結(jié)構(gòu)跳躍到阻尼比較低的另一階振型上振動(dòng),從而揭示了振型跳躍的內(nèi)在原因�；谏鲜龇治�,可認(rèn)為膜結(jié)構(gòu)的氣彈失穩(wěn)是一種由旋渦脫落誘發(fā)的渦激共振現(xiàn)象,具有振幅突然增大、主導(dǎo)振型出現(xiàn)跳躍、總阻尼迅速衰減等特征。4.采用解析方法推導(dǎo)了膜結(jié)構(gòu)的附加質(zhì)量和氣動(dòng)阻尼計(jì)算公式�；跉鈩�(dòng)聲學(xué)理論和擬靜態(tài)理論,推導(dǎo)了均勻流中開敞式單向張拉膜結(jié)構(gòu)的附加質(zhì)量及氣動(dòng)阻尼解析公式。該方法將作用在膜面的風(fēng)荷載簡(jiǎn)化為氣動(dòng)聲壓和擬靜態(tài)風(fēng)壓兩部分,前者由膜面振動(dòng)對(duì)空氣的擠壓作用引起,與來(lái)流風(fēng)速無(wú)關(guān),可采用氣動(dòng)聲學(xué)方法確定;后者與來(lái)流作用下膜面的擬靜態(tài)風(fēng)壓有關(guān),反映了膜面振動(dòng)過(guò)程中形狀變化對(duì)風(fēng)荷載的影響,可通過(guò)對(duì)一個(gè)振動(dòng)周期內(nèi)不同時(shí)刻結(jié)構(gòu)形狀的風(fēng)荷載CFD數(shù)值模擬來(lái)確定。與氣彈模型風(fēng)洞試驗(yàn)結(jié)果對(duì)比表明,附加質(zhì)量解析公式的誤差不超過(guò)9.0%,氣動(dòng)阻尼解析公式的誤差也基本可以控制在20%以內(nèi)。進(jìn)一步分析表明:附加質(zhì)量和氣動(dòng)阻尼均隨著風(fēng)速的增大而增大,附加質(zhì)量可達(dá)結(jié)構(gòu)質(zhì)量的5倍左右,氣動(dòng)阻尼可達(dá)結(jié)構(gòu)阻尼的10倍左右,因而在膜結(jié)構(gòu)風(fēng)振分析中附加氣動(dòng)力作用不可忽視。5.提出了考慮氣彈失穩(wěn)的膜結(jié)構(gòu)抗風(fēng)設(shè)計(jì)方法。在現(xiàn)有膜結(jié)構(gòu)抗風(fēng)設(shè)計(jì)流程的基礎(chǔ)上,增加了臨界風(fēng)速判定和附加氣動(dòng)力評(píng)估環(huán)節(jié),以考慮氣彈失穩(wěn)和流固耦合的影響。在此基礎(chǔ)上,給出了氣彈失穩(wěn)臨界風(fēng)速的定義和一些典型工況下的取值建議,以及附加氣動(dòng)力的確定方法。此外,還結(jié)合氣彈模型風(fēng)洞試驗(yàn)結(jié)果探討了預(yù)張力對(duì)結(jié)構(gòu)臨界風(fēng)速的影響,提出通過(guò)改變預(yù)張力來(lái)改善結(jié)構(gòu)氣動(dòng)穩(wěn)定性的建議。
[Abstract]:Because of its soft characteristics, membrane structure will produce larger deformation and vibration under wind load. This deformation and vibration, in turn, affect the flow field around the structure, forming a so-called "fluid solid coupling effect". Under specific conditions, the fluid solid coupling effect will lead to a sharp increase in structural amplitude with wind speed, which produces similar bridges and wings. The study of the mechanism of its action has been one of the most important topics in the field of structural wind engineering. However, the work in this field is mostly concentrated on the structure of the bridge, and the study of the membrane structure is very few. One of the important reasons is the dynamic characteristics of the membrane structure. It is very complicated that it is difficult to simplify the segment model as a bridge, which only has translational and rotational degrees of freedom. In recent years, the damage events of large membrane structures at home and abroad have occurred in strong wind, which indicates that the theory of wind resistant design for membrane structures at the present stage still has some shortcomings. It is necessary to further explore the wind induced dynamic catastrophe of membrane structure. On the basis of the above background, the wind tunnel test of a series of membrane structures is carried out in this paper. The mechanism of the interaction between the structure and the wind field is clarified, and the mechanism of the aeroelastic instability of the membrane structure is revealed, and the mechanism of the aeroelastic instability is revealed. The main work includes the following aspects: 1. the aerodynamic instability research method of membrane structure based on the full load domain and multiple response characteristics is established. In view of the characteristics of the geometrically nonlinear and multi order modal parameters of the wind vibration response of the membrane structure, the traditional structural aeroelastic instability research is studied. The method is no longer applicable. It is necessary to establish an aeroelastic instability study method suitable for the flexible system with multiple degrees of freedom. Therefore, a comprehensive study method of aerodynamic instability of membrane structures based on the full load domain and multiple response characteristics is proposed. The method is based on the wind tunnel test of the aeroelastic model, and the structure response characteristics and the flow are combined with the numerical simulation and analytical method. In the two aspects of the law of field change, by investigating the correlation between the structure response and the flow velocity of the flow field under the different wind speed (full load field), and the variation of the characteristic parameters such as the structure amplitude, the dominant vibration and the damping ratio of the system, the mechanism of the aeroelastic instability of the membrane structure is revealed. On the basis of the establishment of the overall research framework, some key technologies are set up. The problem, such as modal identification method, damping identification method and CFD numerical simulation method based on dynamic boundary technology, has been discussed, and its effectiveness.2. is verified and a series of typical membrane structure aeroelastic model wind tunnel tests have been completed. The wind tunnel test of aeroelastic model has always been a difficult problem in the field of structural wind engineering, especially the gas of membrane structure. It is the key problem to solve the problem of how to choose the suitable model material and how to avoid the interference between the wind field and the structural vibration of the measuring device. Based on the similarity theory of the aeroelastic model, the non-contact measurement technology and the pretension method, the open type unidirectional tensioned membrane structure is designed and completed. In the wind tunnel test of closed one-way tensioned membrane structure and saddle shaped membrane structure aeroelastic model, the wind vibration response and the change data of the surface wind field under different wind speeds are obtained. Through the analysis of the variation of the structure amplitude and the dominant mode at different wind speeds, it is found that there is a sharp increase in the amplitude of the vibration amplitude and the leading mode of the mode jump. In order to judge the phenomenon and the structural gas elastic instability,.3. combined with a variety of research means to reveal the mechanism of aeroelastic instability of the membrane structure. Through the analysis of the displacement response and wind velocity correlation of the structure under the full load domain, the wind velocity interval of the aeroelastic instability is determined, and the dominant frequency and wind of the structural displacement are further investigated by the spectrum analysis. In order to verify this phenomenon, the CFD numerical simulation of the average structure and forced vibration is carried out to verify this phenomenon. It is found that the vortex shedding frequency of the structure surface changes with the change of the structure balance structure, and it is found that the vortex shedding frequency of the structure surface changes as the structure balance structure changes. The large oscillation of the structure will be triggered when the structure of a certain order of vibration frequency is close, and this large oscillation also controls the vortex shedding frequency, which leads to the locking phenomenon. In addition, the change of the total damping ratio of the system with the wind speed is also analyzed, and it is found that the increase of the wind speed increases first and then decreases with the wind speed, and the peak point coincide with the occurrence of the wind velocity. This phenomenon can be interpreted as a rapid increase in damping ratio of the dominant structure caused by aerodynamic damping, which forces the structure to jump to the other order of the lower damping vibration, and thus reveals the internal cause of the mode jump. Based on the above analysis, it is considered that the aerodynamic instability of the membrane structure is a kind of cause. The vortex induced vortex induced resonance phenomenon, which has a sudden increase in amplitude, a jump in the dominant mode and the rapid attenuation of the total damping, is used to deduce the additional mass and aerodynamic damping formula of the membrane structure by analytic method. Based on the theory of aeroacoustics and quasi-static theory, the open type unidirectional tensile membrane structure in the uniform flow is derived. The analytical formula of additional mass and aerodynamic damping is formulated. This method simplifies the wind load acting on the membrane surface as two parts of the aerodynamic pressure and the pseudo static pressure. The former is caused by the extrusion of the membrane surface vibration to the air, and is independent of the wind velocity. The latter is determined by the aerodynamic acoustics. The latter is related to the pseudo static pressure of the membrane surface. The influence of the shape change on the wind load during the film surface vibration can be determined by the CFD numerical simulation of the wind load at different moments in the vibration period. The error of the analytical formula of the added mass is not more than 9%, and the error of the analytical formula of the aerodynamic damping can also be basically controlled. The further analysis shows that the additional mass and aerodynamic damping increase with the increase of wind speed, the additional mass can reach about 5 times of the structure mass, and the aerodynamic damping can reach about 10 times of the structural damping, so the addition of aerodynamic force to the wind vibration analysis of the membrane structure can not be ignored by.5. to consider the wind resistance of the membrane structure to resist the wind. On the basis of the current wind resistance design flow of the membrane structure, the critical wind speed determination and the additional aerodynamic evaluation link are added to consider the influence of the aeroelastic instability and the fluid solid coupling. On this basis, the definition of the critical wind speed of the aeroelastic instability and some suggestions on the value under typical conditions, as well as the determination of the additional aerodynamic force are given. In addition, the effect of pretension on the critical wind speed of the structure is discussed in combination with the wind tunnel test results of the aeroelastic model, and a proposal to improve the aerodynamic stability of the structure by changing the pretension is proposed.

【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類號(hào)】：TU383;TU352.2

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本文編號(hào)：1777950