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机构地区:[1]黑龙江科技大学建筑工程学院,黑龙江哈尔滨150022
出 处:《兰州理工大学学报》2017年第4期127-131,共5页Journal of Lanzhou University of Technology
基 金:黑龙江省自然科学基金资助项目(E201460)
摘 要:以断裂力学及断裂有限元相关理论为基础,用ANSYS有限元软件建立完整梁和带裂缝梁并对其进行静力分析.在不同荷载作用下,比较完整梁和带裂缝梁的挠度、拉应力、压应力和切应力等受力变化.在标定荷载作用下,分析裂缝长度、深度及宽度对主梁受力的影响,计算不同裂缝尺寸下的应力强度因子.结果表明:相同荷载条件下,带裂缝梁由于裂缝尖端存在应力集中,混凝土所受拉应力比同一完整梁明显变大;在常量荷载作用下,随着裂缝尺寸的增加,裂缝尖端应力场强度增大,应力强度因子增大,发生断裂的可能性增大;对于本文中带裂缝20m预应力混凝土简支梁来说,当裂缝宽度为0.25mm时,会发生脆性断裂,因此要控制裂缝宽度小于0.25mm.The fracture mechanics and related theory of fracture finite element were taken as investigation basis to create an intact beam and a cracked beam and conduct their static analysis by means of finite ele- ment software ANSYS. The variation of their deflection, tensile stress, compressive stress, and shearing stress was compared with each other under different loading conditiorL The effect of crack length, depth, "and width on the stress in main beam was analyzed under calibrated loading condition and the stress intensity factor was calculated in the case of different crack sizes. The result shows that, under the same loading condition, the tensile stress in concrete of cracked beam will be remarkably larger than that of intact beam due to the stress concentration at the crack tip in the former beam. Under constant load condition, the stress field intensity at crack tip will increase with the size increase of crack, so that the stress intensity factor increases and will be a possibility of rupture with the beam. For the 20 m slab beam with crack, when the width of crack is 0. 25 mm, the brittle fracture will occur. Therefore, it is necessary to control the crack width less than 0. 25 mm.
关 键 词:裂缝 断裂力学 预应力混凝土简支空心板梁 应力强度因子 断裂有限元
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