开孔冷弯薄壁复杂卷边槽钢受弯构件稳定性能

发布时间：2018-02-28 20:17

本文关键词： 冷弯薄壁型钢稳定性能抗弯承载力腹板开孔直接强度法　出处：《沈阳建筑大学》2014年硕士论文　论文类型：学位论文

【摘要】：稳定问题一直是冷弯薄壁型钢结构研究的重点。随着冷弯薄壁型钢构件向高强、超薄的方向发展,截面形式也日趋复杂,这使得构件的屈曲模式也变得更加复杂。而孔洞的开设改变了构件的应力分布,影响板件间的相关作用,对构件稳定性能影响明显。因此,开孔截面冷弯薄壁型钢构件的稳定性能有待深入研究。本文选取了腹板开孔复杂卷边C形和腹板开孔复杂卷边∑形两种截面形式的冷弯薄壁型钢构件,利用试验研究和有限元相结合的方法对其在纯弯和非纯弯两种状态下的稳定性能进行了研究。本文对腹板开孔复杂卷边槽钢(B1截面)、∑形复杂卷边槽钢(B2截面)共计8根简支梁进行了试验研究,其中纯弯试件4根,非纯弯试件4根。试验结果表明：B2截面试件的抗弯承载效率均高于B1截面试件,B1截面试件受开孔的影响较大,而B2截面试件,由于腹板加劲肋的设置减弱了开孔对截面的影响,两者在开孔处均发生了明显的剪切变形。与相同条件下不开孔构件的试验结果对比表明：开孔构件的极限荷载均有不同程度的降低,非纯弯状态的下降幅度大于纯弯状态；开孔构件的失稳模式基本不变,但破坏位置多发生在孔洞截面处。此外,对试验进行了有限元模拟,计算结果与试验结果吻合良好。在此基础上,利用有限元模拟对比了相同截面腹板开孔和不开孔受弯构件的应力分布云图,结果表明孔洞的存在改变了构件的应力分布,使孔洞周边区域发生应力集中现象,B1截面开孔受弯构件最大应力主要集中在弯剪段孔洞附近,而B2截面开孔后最大应力则主要集中在荷载作用点附近的受压翼缘上由于求解受弯构件极限承载力的有效截面法过于复杂并且不适用于畸变屈曲承载力的计算,而美国和澳大利亚规范中规定的截面形式和宽高比H/B等与我国实际情况也有所差异,本文针对普通卷边槽钢简支梁简化计算方法进行研究。首先,分别用国外直接强度法、国内学者提出的直接强度法和本文提出的直接强度法计算了58个构件的极限承载力。并将以上计算结果与已有试验结果和有效截面法计算结果进行对比,发现本文提出的计算公式的计算误差较小,符合工程应用的精度要求。
[Abstract]:The stability problem has always been the focus of the research on cold-formed thin-walled steel structures. With the development of cold-formed thin-walled steel members towards the direction of high strength and ultra-thin, the cross-section form is becoming more and more complex. This makes the buckling mode of the member more complicated, and the opening of the hole changes the stress distribution of the member, affects the correlation between the plates, and has an obvious effect on the stability of the member. The stability of cold-formed thin-walled steel members with open-hole section needs to be studied. In this paper, two types of cold-formed thin-walled steel members are selected, which are the C shape of web opening complicated crimping and the sigma-delta shape of web opening complex crimping. In this paper, the stability of the steel under pure bending and non-pure bending is studied by means of experimental study and finite element method. In this paper, the section B _ 1 and section B _ 2 of complex crimping channel steel with web openings are studied. A total of 8 simply supported beams were tested. There are 4 pure bending specimens and 4 non-pure bending specimens. The results show that the bending loading efficiency of the specimens with the section of: B2 is higher than that of the specimens with section B1 and section B1, but the specimens with the section B2 are greatly affected by the opening hole. The influence of the opening on the section is weakened by the stiffening rib of the web plate. Compared with the experimental results of non-perforated members under the same conditions, the ultimate loads of the open-hole members are reduced to some extent, and the decrease of non-pure bending state is larger than that of pure bending state. The instability mode of the perforated member is basically unchanged, but the failure location mostly occurs at the section of the hole. In addition, the finite element simulation of the test is carried out, and the calculated results are in good agreement with the experimental results. The finite element simulation is used to compare the stress distribution of the same section web with and without opening. The results show that the existence of the hole changes the stress distribution of the member. The stress concentration phenomenon occurs in the surrounding area of the hole. The maximum stress of the bending member with the opening hole in the B1 section is mainly concentrated near the hole in the bending shear section. However, the maximum stress of B2 section is mainly concentrated on the flange near the loading point because the effective section method for calculating ultimate bearing capacity of flexural members is too complicated and not suitable for the calculation of buckling capacity. However, the section form and aspect ratio H / B specified in the codes of the United States and Australia are also different from the actual situation in China. In this paper, the simplified calculation method for the simple supported beam of common crimped channel steel is studied. Firstly, the direct strength method is used in foreign countries respectively. The ultimate bearing capacity of 58 members has been calculated by the direct strength method proposed by domestic scholars and the direct strength method proposed in this paper. It is found that the calculation error of the formula presented in this paper is relatively small, which accords with the requirement of engineering application precision.
【学位授予单位】：沈阳建筑大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU392.1

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