發(fā)布時間：2018-11-28 14:59

【摘要】：伴隨著建筑鋼結構的巨大發(fā)展，鋼結構厚板經常應用在高層、大跨建筑，，橋梁，海洋平臺，壓力容器及船體結構中。隨著鋼板厚度及焊縫尺寸增加，承受荷載更加復雜，拘束作用更加突出，以及局部地區(qū)頻繁出現低溫，鋼結構厚板發(fā)生Z向破壞的可能性也越來越大。本文對鋼厚板裂紋受厚度方向荷載時的斷裂韌性進行了有限元分析，對鋼結構厚板及其連接焊縫的Z向性能進行了實驗研究，最后提出基于強度和韌性指標的Z向性能鋼材選材及設計方法。主要成果如下： （1）對幾種典型的厚板及其連接內裂紋進行有限元模擬，對裂紋分布、共生裂紋間距、鋼板厚度等加以考慮，分析斷裂參數K、J的變化規(guī)律，為實際中厚板的斷裂分析提供參考。 （2）針對Q345B鋼材60~165mm幾種不同厚度的鋼板，對其母材和十字形焊接連接熱影響區(qū)，以及對接連接進行取樣。取樣類型分為沿軋制方向（X向）和厚度方向（Z向），并在-60℃~20℃下進行簡單拉伸試驗，得到屈服、極限強度f_y、f_u及斷面收縮率Z隨板厚、焊縫尺寸、取樣類型及溫度等的變化規(guī)律。 （3）針對Q345B鋼材60~165mm幾種不同厚度的鋼板，對其母材和十字形焊接連接熱影響區(qū)，以及對接連接進行取樣。取樣類型分為沿軋制方向（X向）和厚度方向（Z向），并在-60℃~20℃下進行夏比V形缺口沖擊試驗，得到沖擊功Akv隨板厚、焊縫尺寸、取樣類型及溫度等的變化規(guī)律。 （4）針對Q345B鋼材60~165mm幾種不同厚度的鋼板，對其母材和十字形焊接連接熱影響區(qū)進行取樣。取樣類型分為沿軋制方向（X向）和厚度方向（Z向），并在-60℃~20℃下進行三點彎斷裂試驗，得到斷裂韌性指標CTOD值隨板厚、焊縫尺寸、取樣類型及溫度等的變化規(guī)律。 （5）在試驗基礎上，針對現有規(guī)范的結構Z向性能敏感性評價標準，修正和補充了基于拉伸力學性能的評價方法，并增加了基于沖擊和斷裂韌性的評價方法。考慮了溫度的影響作用，并針對不同板厚提出具體的敏感指標確定建議。
[Abstract]:With the great development of building steel structures, steel thick plates are often used in high-rise, large-span buildings, bridges, offshore platforms, pressure vessels and hull structures. With the increase of steel plate thickness and weld size, the load is more complex, the restraint effect is more prominent, and the low temperature occurs frequently in the local area, the possibility of Z-direction failure of thick plate of steel structure is more and more large. In this paper, the fracture toughness of thick steel plate under the load of thickness direction is analyzed by finite element method, and the Z-direction behavior of thick plate and joint weld of steel structure is studied experimentally. Finally, the material selection and design method of Z direction performance steel based on strength and toughness index are put forward. The main results are as follows: (1) several typical thick plates and their internal cracks are simulated by finite element method. The distribution of cracks, the spacing of symbiotic cracks and the thickness of steel plate are taken into account. It provides a reference for the fracture analysis of practical plate. (2) for Q345B steel 60~165mm steel plate with different thickness, the base metal, the heat affected zone of cross-welded joint and the butt connection are sampled. The sampling types are divided into the direction of rolling (X direction) and the direction of thickness (Z direction), and the simple tensile tests are carried out at -60 鈩

本文編號：2363210