本文選題：棘輪邊界　切入點：安定性　出處：《武漢工程大學(xué)》2016年碩士論文

【摘要】：壓力管道和壓力容器廣泛應(yīng)用于化工,石油,軍事和核電站等領(lǐng)域。這些構(gòu)件通常承受穩(wěn)定載荷和循環(huán)載荷的一個組合載荷,由于過量的塑性變形累積,而發(fā)生棘輪失效,嚴重影響安全性。由于理論推導(dǎo)的復(fù)雜性,世界各國標準中僅包含循環(huán)熱-內(nèi)壓載荷下薄壁圓筒棘輪極限解析解(Bree圖),尚缺乏復(fù)雜載荷下壓力管道棘輪極限解析解。為保障復(fù)雜載荷工況下壓力管道的安全性,本文采用非循環(huán)法系統(tǒng)地推導(dǎo)了工程領(lǐng)域中常見復(fù)雜循環(huán)組合載荷下壓力管道棘輪極限的解析解,并提出了相應(yīng)的設(shè)計方法,主要工作及結(jié)論如下:(1)由重力等因素引起的軸向壓縮應(yīng)力會顯著降低結(jié)構(gòu)的棘輪極限。壓力管道的棘輪極限會隨著徑比的增大而顯著增加。(2)本文所提出的設(shè)計方法的特征是采用Von-Mises屈服準則,將承壓外殼的組合載荷條件分為穩(wěn)定載荷和循環(huán)載荷兩部分。推導(dǎo)出的這些復(fù)雜載荷條件下壓力管道棘輪極限包括:循環(huán)溫度梯度和恒定內(nèi)壓組合載荷下壓力管道的棘輪極限,循環(huán)溫度梯度和恒定內(nèi)壓組合載荷下壓縮端壓力管道的棘輪極限,循環(huán)溫度梯度和恒定彎矩組合載荷下壓力管道的棘輪極限,循環(huán)溫度梯度和恒定扭矩組合載荷下壓力管道的棘輪極限,循環(huán)溫度梯度和恒定彎扭組合載荷下壓力管道的棘輪極限,循環(huán)扭矩和恒定內(nèi)壓組合載荷下壓力管道的棘輪邊界,循環(huán)扭矩和恒定彎矩組合載荷下壓力管道的棘輪邊界,循環(huán)彎矩和恒定扭矩組合載荷下壓力管道的棘輪邊界,以及循環(huán)彎矩載荷下內(nèi)壓直管的棘輪極限的解析解。(3)實驗測試了500℃溫度下20CrMo鋼的單軸拉伸試驗和單軸棘輪試驗。結(jié)合實驗數(shù)據(jù)分析了20CrMo鋼的棘輪效應(yīng)演變規(guī)律,最終確定了其棘輪極限的范圍為200MPa~300 MPa。(4)本文所得到的解拓展了經(jīng)典Bree評定圖的適用范圍,而且壓力管道在循環(huán)熱-機械載荷及類似工況下的棘輪極限能夠采用所提出的相應(yīng)設(shè)計方法進行評估,這種方法在工程上的適用性也很廣泛,為復(fù)雜載荷條件下壓力管道的棘輪極限工程設(shè)計奠定理論基礎(chǔ)。
[Abstract]:Pressure pipes and pressure vessels are widely used in chemical, petroleum, military and nuclear power plants.These components usually bear a combined load of stable load and cyclic load. Due to the accumulation of excessive plastic deformation ratchet failure occurs which seriously affects the safety.In order to ensure the safety of pressure pipeline under complex load condition, the analytical solution of ratchet limit of pressure pipeline under common complex cyclic combined loads in engineering field is deduced systematically by using the non-cyclic method, and the corresponding design method is put forward.The main work and conclusions are as follows: (1) the axial compression stress caused by gravity and other factors can significantly reduce the ratchet limit of the structure.The ratchet limit of pressure pipeline will increase significantly with the increase of diameter ratio. The characteristic of the design method proposed in this paper is that the combined load condition of the confined shell can be divided into two parts: stable load and cyclic load using Von-Mises yield criterion.The ratchet limit of pressure pipeline under these complex load conditions is derived, which includes the ratchet limit of pressure pipeline under cyclic temperature gradient and constant internal pressure combined load.Ratchet limit of compression end pressure pipeline under cyclic temperature gradient and constant internal pressure combined load, ratchet limit of pressure pipe under cyclic temperature gradient and constant bending moment,Ratchet limit of pressure pipeline under combined load of cyclic temperature gradient and constant torque, ratchet limit of pressure pipe under combined load of cyclic temperature gradient and constant bending and torsion, ratchet boundary of pressure pipeline under combined load of cyclic torque and constant internal pressure,Ratchet boundary of pressure pipeline under combined load of cyclic torque and constant bending moment, ratchet boundary of pressure pipe under combined load of cyclic moment and constant torque,The uniaxial tensile test and uniaxial ratchet test of 20CrMo steel at 500 鈩，

本文編號：1687386