冷弯薄壁型钢C形梁受剪性能研究

发布时间：2018-11-12 16:42

【摘要】：当冷弯薄壁型钢C形梁跨度较小即短梁时,发生受剪破坏。本文在冷弯薄壁型钢C形梁受剪试验的基础上,验证了有限元方法的正确性,然后进行了大量有限元变参数分析,最终对冷弯薄壁型钢C形梁腹板的剪切应力进行折算,提出了冷弯薄壁型钢C形梁受剪承载力的计算方法。本文首先对冷弯薄壁型钢C形梁受剪试验进行了简要介绍,包括试验试件设计、试验装置、加载制度、试件破坏特征、荷载—位移曲线以及受剪承载力等内容。然后采用ABAQUS有限元软件,通过数值模拟分析了已有试验中的11个冷弯薄壁型钢C形梁试件的受剪性能。将有限元计算结果与试验结果进行了对比分析,包括受剪承载力、荷载—位移曲线、试件破坏特征等,对比结果表明有限元分析结果与试验结果二者较为吻合,验证了有限元方法的正确性和可行性。在此基础之上,采用相同的有限元方法,分别对试件的腹板高厚比h/t、腹板厚度t、剪跨比a/h及钢材强度四个因素对冷弯薄壁型钢C形梁受剪性能的影响进行有限元变参数分析。分析表明:冷弯薄壁型钢C形梁的受剪承载力和刚度随着腹板厚度的增加而有明显的增加;但是,当冷弯薄壁型钢C形梁的腹板厚度过薄则易导致C形梁发生翼缘局部压曲。此外,增大腹板的高厚比,冷弯薄壁型钢C形梁受剪承载力也会有很大提高。梁剪跨比改变主要影响的是冷弯薄壁型钢C形梁破坏特征。钢材强度增强也会使冷弯薄壁型钢C形梁的受剪承载力有很大提高,但是其对冷弯薄壁型钢C形梁的刚度几乎没有影响。最后,在大量有限元变参数分析的基础上,考虑冷弯薄壁型钢C形梁的翼缘和卷边对腹板的影响,对腹板剪切应力进行修正。把冷弯薄壁型钢C形梁的受剪承载力计算公式按照受力状态分为受剪屈服、弹性剪切屈曲以及非弹性剪切屈曲三种承载力公式,并将理论计算结果、有限元结果和试验结果进行对比,验证了修正理论公式的正确性,为冷弯薄壁型钢C形梁受剪承载力计算提供了设计依据。
[Abstract]:The shear failure occurs when the span of C beam is smaller than that of short beam. In this paper, based on the shear test of cold-formed thin-walled steel C-shaped beam, the correctness of finite element method is verified, and then a large number of finite element variable parameter analysis is carried out, finally, the shear stress of the cold-formed thin-walled steel C-shaped beam web plate is converted. A method for calculating the shear capacity of C-shaped cold-formed thin-walled steel beams is presented. In this paper, the shear test of cold-formed thin-walled steel C-shaped beam is introduced briefly, including the design of test specimen, test device, loading system, failure characteristics of specimen, load-displacement curve and shear bearing capacity, etc. Then the shear behavior of 11 cold-formed thin-walled steel C-shaped beam specimens in existing tests is analyzed by numerical simulation using ABAQUS finite element software. The finite element analysis results are compared with the test results, including shear capacity, load-displacement curve, failure characteristics of the specimen, etc. The results show that the finite element analysis results are in good agreement with the test results. The correctness and feasibility of the finite element method are verified. On this basis, the same finite element method is used to analyze the ratio of height to thickness of the web, the thickness of the web, and the thickness of the web. The influence of shear span ratio (a / h) and steel strength on shear behavior of cold-formed thin-walled steel C-beam is analyzed by finite element method. The analysis shows that the shear capacity and stiffness of cold-formed thin-walled C-shaped beams increase obviously with the increase of web thickness, but when the web thickness of cold-formed thin-walled C-shaped beams is too thin, the flange local compression will occur easily. In addition, the shear capacity of cold-formed thin-walled C-beam can be greatly improved by increasing the ratio of high to thick web. The failure characteristics of cold-formed thin-walled C-beam are mainly affected by the change of shear span ratio. The strength of steel also increases the shear capacity of cold-formed thin-walled steel C-beam, but it has little effect on the stiffness of cold-formed thin-walled C-beam. Finally, on the basis of a large number of finite element variable parameter analysis, considering the influence of flange and crimping on web plate of cold-formed thin-walled steel C-shaped beam, the shear stress of web plate is corrected. The formulas for calculating the shear capacity of cold-formed thin-walled steel C-shaped beams are divided into three kinds of bearing capacity formulas: shear yield, elastic shear buckling and inelastic shear buckling according to the stress state, and the theoretical calculation results are given. By comparing the finite element results with the experimental results, the correctness of the modified theoretical formula is verified, which provides the design basis for the calculation of the shear capacity of the cold-formed thin-walled steel C-shaped beams.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU392.1

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