【摘要】：本文以普灣16號公路橋為項目背景,通過數(shù)值模擬和試驗,研究拱橋吊耳結(jié)構(gòu)的疲勞性能。實驗選擇荷載幅時,通過計算比較美國標(biāo)準(zhǔn)AASHTO,英國標(biāo)準(zhǔn)BS5400以及歐洲標(biāo)準(zhǔn)Eurocodel,最終確定最為保守的荷載幅值為實驗荷載；在200萬次恒幅加載實驗過程中,每50萬次對吊耳測點進(jìn)行測定,測點應(yīng)力、應(yīng)變基本呈線性變化,結(jié)構(gòu)整體處于線彈性狀態(tài)。采用考慮施工工藝的Sr-N曲線進(jìn)行處理,吊耳結(jié)構(gòu)中焊縫疲勞性能符合設(shè)計要求。為更好地評估吊耳的疲勞性能,對構(gòu)件疲勞壽命進(jìn)行模擬計算,通過調(diào)整應(yīng)力幅的大小,畫出不同材料的吊耳的S-N曲線,對比吊耳S-N曲線和其所用材料的S-N曲線圖形情況。應(yīng)用雨流法統(tǒng)計隨機(jī)荷載,把隨機(jī)的荷載簡化為交變荷載疊加,研究吊耳在變幅荷載作用下的疲勞性能。比較在等幅交變荷載和隨機(jī)交變荷載作用下吊耳疲勞壽命的大小,發(fā)現(xiàn)隨機(jī)交變荷載下吊耳的疲勞壽命相比較小,變幅荷載下的疲勞壽命是更加保守的,而現(xiàn)在的設(shè)計規(guī)范都是以恒幅荷載為理論基礎(chǔ),所以確定正確的設(shè)計荷載,找到更加符合實際情況的疲勞荷載幅,對疲勞的研究與設(shè)計有著非常重要的意義。在相對損傷的計算過程中,發(fā)現(xiàn)構(gòu)件相對損傷既沒有集中在低應(yīng)力幅附近,也沒在較高的應(yīng)力幅附近,大都集中在應(yīng)力幅和循環(huán)次數(shù)較為適中的位置,因此,循環(huán)次數(shù)和應(yīng)力幅度對材料相對損傷的影響有著至關(guān)重要的作用。采用雙軸受力指示系數(shù)判斷構(gòu)件受力狀態(tài),通過對整體結(jié)構(gòu)受力狀態(tài)判定之后,結(jié)構(gòu)在連接部位受力復(fù)雜,可為吊耳設(shè)計與計算提供有價值參考。
[Abstract]:Taking Puwan No. 16 Highway Bridge as the project background, this paper studies the fatigue performance of arch bridge hoisting ear structure by numerical simulation and test. When the load amplitude is selected, the most conservative load amplitude is determined by calculating and comparing the American standard AASHTO, the British standard BS5400, and the European standard Eurocodel,. In the course of 2 million constant amplitude loading experiments, the measuring points were measured every 500000 times. The stress and strain of the measuring points were basically linear, and the whole structure was in a linear elastic state. The fatigue behavior of the weld seam in the hoist structure meets the design requirements by using the Sr-N curve considering the construction technology. In order to better evaluate the fatigue performance of the hoists, the fatigue life of the members is simulated and calculated. By adjusting the stress amplitude, the S-N curves of the hoists of different materials are drawn. The S-N curves of the lifting ears and the S-N curves of the materials used were compared. The random load is simplified as alternating load superposition by the method of rain flow, and the fatigue behavior of the hoist under variable amplitude load is studied. Comparing the fatigue life of the hoist under the constant amplitude alternating load and random alternating load, it is found that the fatigue life of the hoist under random alternating load is smaller than that under the variable amplitude load, and the fatigue life under the variable amplitude load is more conservative. Now the design code is based on constant amplitude load, so it is very important for fatigue research and design to determine the correct design load and find the fatigue load which is more in line with the actual situation. In the calculation of relative damage, it is found that the relative damage of the component is not concentrated in the vicinity of the low stress amplitude or the higher stress amplitude, but mostly in the position where the stress amplitude and the number of cycles are relatively moderate. The number of cycles and the magnitude of stress play an important role in the relative damage of materials. The biaxial force indication coefficient is used to judge the stress state of the member. After judging the stress state of the whole structure, the structure is complicated in the connection position, which can provide a valuable reference for the design and calculation of the hoist.
【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：U441.4;U448.22

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本文編號：2418172