拱桥吊耳结构疲劳性能分析与试验研究
发布时间：2019-01-30 13:31
【摘要】：本文以普湾16号公路桥为项目背景,通过数值模拟和试验,研究拱桥吊耳结构的疲劳性能。实验选择荷载幅时,通过计算比较美国标准AASHTO,英国标准BS5400以及欧洲标准Eurocodel,最终确定最为保守的荷载幅值为实验荷载；在200万次恒幅加载实验过程中,每50万次对吊耳测点进行测定,测点应力、应变基本呈线性变化,结构整体处于线弹性状态。采用考虑施工工艺的Sr-N曲线进行处理,吊耳结构中焊缝疲劳性能符合设计要求。为更好地评估吊耳的疲劳性能,对构件疲劳寿命进行模拟计算,通过调整应力幅的大小,画出不同材料的吊耳的S-N曲线,对比吊耳S-N曲线和其所用材料的S-N曲线图形情况。应用雨流法统计随机荷载,把随机的荷载简化为交变荷载叠加,研究吊耳在变幅荷载作用下的疲劳性能。比较在等幅交变荷载和随机交变荷载作用下吊耳疲劳寿命的大小,发现随机交变荷载下吊耳的疲劳寿命相比较小,变幅荷载下的疲劳寿命是更加保守的,而现在的设计规范都是以恒幅荷载为理论基础,所以确定正确的设计荷载,找到更加符合实际情况的疲劳荷载幅,对疲劳的研究与设计有着非常重要的意义。在相对损伤的计算过程中,发现构件相对损伤既没有集中在低应力幅附近,也没在较高的应力幅附近,大都集中在应力幅和循环次数较为适中的位置,因此,循环次数和应力幅度对材料相对损伤的影响有着至关重要的作用。采用双轴受力指示系数判断构件受力状态,通过对整体结构受力状态判定之后,结构在连接部位受力复杂,可为吊耳设计与计算提供有价值参考。
[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.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441.4;U448.22
本文编号：2418172
[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.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441.4;U448.22
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，本文编号：2418172
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