往复荷载下钢管与螺栓球组配试件超低周疲劳断裂试验研究
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摘要
为探索螺栓球网格结构强震下的破坏特征,对五个螺栓球节点管球组配试件进行了轴向往复荷载作用下的超低周疲劳断裂试验研究。通过电镜扫描观察试件超低周疲劳破坏的裂纹萌生、扩展、断裂、断口形态,并分析了裂纹萌生原因、断裂机理。结果表明:当承受拉-压循环荷载时,试件均经历失稳弯曲、在杆件中点附近局部凹陷、在凹陷处表面萌生裂纹、进一步开裂、最后发生低周疲劳断裂的过程;其断口形状为椭圆,有明显塑性变形,为韧性断裂,疲劳寿命均很短。当试件承受较大压幅值的循环荷载时,试件首先失稳弯曲,然后在杆件中点附近局部凹陷,继而在凹陷处表面萌生裂纹,但同时因节点中高强螺栓承受弯剪作用,在螺栓牙底应力集中位置,也多处同时萌生裂纹并迅速发展,最后导致高强螺栓先于杆件局部凹陷处发生疲劳断裂;其断口表面光滑平整,没有明显塑性变形,疲劳寿命只有18次。
In order to explore the damage characteristics of the bolt-ball grid structure under strong earthquake,The ultra-low-cycle fatigue fracture test of the five Bolt-ball-tube assembly components under axial reciprocating load was studied. Scanning electron microscopy was used to observe crack initiation,propagation,fracture and fracture morphology in ultra-low-cycle fatigue failure of the specimen,and the cause of crack initiation and fracture mechanism were analyzed. The results show that when subjected to tensile-compressive cyclic loading,the specimens first destabilize and bend,then partially dent in the vicinity of the midpoint of the rod,and then initiate cracks on the surface of the depression,further cracking,and finally low-cycle fatigue fracture. Its fracture shape is ellipse,there is obvious plastic deformation,it is ductile fracture,its fatigue life is very short; When the test piece is subjected to the pressure-pressure cyclic load that changes more greatly,the test piece is also first bent and then bent The local depression near the midpoint and then the surface initiates cracks at the depressions,but at the same time the high-strength bolts in the nodes are subjected to bending and shearing. At the location of stress concentration in the bottom of the bolts,multiple cracks develop at the same time and develop rapidly. Finally,the highstrength bolts lead to Fatigue fracture occurs in the local depression of the rod. Its fracture surface is smooth and smooth,without obvious plastic deformation,and its fatigue life is only 18 times.
In order to explore the damage characteristics of the bolt-ball grid structure under strong earthquake,The ultra-low-cycle fatigue fracture test of the five Bolt-ball-tube assembly components under axial reciprocating load was studied. Scanning electron microscopy was used to observe crack initiation,propagation,fracture and fracture morphology in ultra-low-cycle fatigue failure of the specimen,and the cause of crack initiation and fracture mechanism were analyzed. The results show that when subjected to tensile-compressive cyclic loading,the specimens first destabilize and bend,then partially dent in the vicinity of the midpoint of the rod,and then initiate cracks on the surface of the depression,further cracking,and finally low-cycle fatigue fracture. Its fracture shape is ellipse,there is obvious plastic deformation,it is ductile fracture,its fatigue life is very short; When the test piece is subjected to the pressure-pressure cyclic load that changes more greatly,the test piece is also first bent and then bent The local depression near the midpoint and then the surface initiates cracks at the depressions,but at the same time the high-strength bolts in the nodes are subjected to bending and shearing. At the location of stress concentration in the bottom of the bolts,multiple cracks develop at the same time and develop rapidly. Finally,the highstrength bolts lead to Fatigue fracture occurs in the local depression of the rod. Its fracture surface is smooth and smooth,without obvious plastic deformation,and its fatigue life is only 18 times.
引文
1李海旺.城市灾难地震避难所与救灾据点规划与设计[M].北京:中国建筑工业出版社,2013Li Haiwang. Planning and design earthquake disaster shelter and relief stronghold in city[M]. Beijing:China Architecture&Building Press.2013
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3 廖芳芳,王伟,陈以一.往复荷载下钢结构节点的超低周疲劳断裂预测[J].同济大学学报(自然科学版),2014,42(4):539-546,617Liao Fangfang,Wang Wei,Chen Yiyi. Extremely low cycle fatigue fracture prediction of steel connections under cyclic loading[J]. Journal of Tongji University(Natural Science),2014,42(4):539-546,617
4 张辰啸.空间双层网格结构强震失效机理与隔震研究[D].哈尔滨:中国地震局工程力学研究所,2016Zhang Chenxiao. Study on the failure mechanism under strong earthquake excitation and isolation of space double-layer lattice structure[D]. Harbin:Institute of Engineering Mechanics,China Earthquake Administration,2016
5 罗云蓉,王清远,刘永杰,等. Q235、Q345钢结构材料的低周疲劳性能[J].四川大学学报(工程科学版),2012,44(2):169-175Luo Yunrong,Wang Qingyuan,Liu Yongjie,et al. Low cycle fatigue properties of steel structure materials Q235 and Q345[J]. Journal of Sichuan University(Engineering Science Edition),2012,44(2):169-175
6 罗云蓉,王清远,于强,等. HRB400Ⅲ级抗震钢筋的低周疲劳性能[J].钢铁研究报,2015,27(6):35-39Luo Yunrong,Wang Qingyuan,Yu Qiang,et al. Low cycle fatigue properties of anti-seismic HRB400 grade III reinforcing steel bar[J].Journal of Iron and Steel Research,2015,27(6):35-39
7 韦尧兵,黄建龙,靳伍银,等.超低周变幅疲劳断裂设计的几个问题[J].甘肃工业大学学报,1998(2):110-113Wei Yaobing,Huang Jianlong,Jin Wuyin,et al. Several problems on extra-low cycle variable amplitude fatigue fracture design[J]. Journal of Gansu University of Technology,1998(2):110-113
8 姜爱华,陈亮,师红旗,等.螺栓疲劳断裂失效分析[J].热加工工艺,2013,42(2):222-223Jiang Aihua,Chen Liang,Shi Hongqi,et al. Fracture analysis of screw bolt[J]. Hot Working Technology,2013,42(2):222-223
9 孟亚惠.高强度螺栓断裂失效分析[J].热加工工艺,2017,46(6):254-255,258Meng Yahui. Analysis of failure reason of high strength bolt[J]. Hot Working Technology,2017,46(6):254-255,258
10 葛荣荣,薛彦涛,牛向阳.国产钢材LYP225的低周疲劳试验研究[J].土木工程报,2017,50(1):12-19,45Ge Rongrong,Xue Yantao,Niu Xiangyang. Experimental study on low-cycle fatigue behavior of Chinese LYP225[J]. China Civil Engeneering Journal,2017,50(1):12-19,45
2 王卓.灾难地震下网架结构体系基于破坏形态的抗震性能设计研究[D].太原:太原理工大学,2015Wang Zhuo. Seismic performance design research of grid architecture based on failure pattern under catastrophic earthquake[D]. Taiyuan:Taiyuan University of Technology,2015
3 廖芳芳,王伟,陈以一.往复荷载下钢结构节点的超低周疲劳断裂预测[J].同济大学学报(自然科学版),2014,42(4):539-546,617Liao Fangfang,Wang Wei,Chen Yiyi. Extremely low cycle fatigue fracture prediction of steel connections under cyclic loading[J]. Journal of Tongji University(Natural Science),2014,42(4):539-546,617
4 张辰啸.空间双层网格结构强震失效机理与隔震研究[D].哈尔滨:中国地震局工程力学研究所,2016Zhang Chenxiao. Study on the failure mechanism under strong earthquake excitation and isolation of space double-layer lattice structure[D]. Harbin:Institute of Engineering Mechanics,China Earthquake Administration,2016
5 罗云蓉,王清远,刘永杰,等. Q235、Q345钢结构材料的低周疲劳性能[J].四川大学学报(工程科学版),2012,44(2):169-175Luo Yunrong,Wang Qingyuan,Liu Yongjie,et al. Low cycle fatigue properties of steel structure materials Q235 and Q345[J]. Journal of Sichuan University(Engineering Science Edition),2012,44(2):169-175
6 罗云蓉,王清远,于强,等. HRB400Ⅲ级抗震钢筋的低周疲劳性能[J].钢铁研究报,2015,27(6):35-39Luo Yunrong,Wang Qingyuan,Yu Qiang,et al. Low cycle fatigue properties of anti-seismic HRB400 grade III reinforcing steel bar[J].Journal of Iron and Steel Research,2015,27(6):35-39
7 韦尧兵,黄建龙,靳伍银,等.超低周变幅疲劳断裂设计的几个问题[J].甘肃工业大学学报,1998(2):110-113Wei Yaobing,Huang Jianlong,Jin Wuyin,et al. Several problems on extra-low cycle variable amplitude fatigue fracture design[J]. Journal of Gansu University of Technology,1998(2):110-113
8 姜爱华,陈亮,师红旗,等.螺栓疲劳断裂失效分析[J].热加工工艺,2013,42(2):222-223Jiang Aihua,Chen Liang,Shi Hongqi,et al. Fracture analysis of screw bolt[J]. Hot Working Technology,2013,42(2):222-223
9 孟亚惠.高强度螺栓断裂失效分析[J].热加工工艺,2017,46(6):254-255,258Meng Yahui. Analysis of failure reason of high strength bolt[J]. Hot Working Technology,2017,46(6):254-255,258
10 葛荣荣,薛彦涛,牛向阳.国产钢材LYP225的低周疲劳试验研究[J].土木工程报,2017,50(1):12-19,45Ge Rongrong,Xue Yantao,Niu Xiangyang. Experimental study on low-cycle fatigue behavior of Chinese LYP225[J]. China Civil Engeneering Journal,2017,50(1):12-19,45