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为了研究高强冷弯薄壁型钢构件的受弯性能和完善直接强度法,对卷边形式为斜卷边、直卷边和复杂卷边的12个G550高强冷弯薄壁Z形钢受弯试件进行了静力试验。试验结果表明,卷边形式对试件屈曲模式和受弯承载力有显著影响,试件发生了局部与畸变相关屈曲或畸变屈曲,直卷边试件的承载力高于斜卷边试件的承载力,复杂Ⅱ型卷边试件的承载力高于复杂Ⅰ型卷边试件的承载力。根据试验结果并结合现有国外直接强度法公式,回归出G550高强冷弯薄壁Z形钢受弯构件发生局部与畸变相关屈曲变形时的承载力直接强度法修正公式,当此类构件发生畸变屈曲时,无需再修正现有直接强度法公式。建立有限元模型对试验进行了分析,分析结果与试验结果吻合良好。在此基础上,利用大量有限元分析结果验证了直接强度法修正公式比现有直接强度法公式对此类构件的承载力的预测更为安全可靠。
In order to study the bending performance of high-strength cold-formed thin-wall steel members and to improve the direct strength method, 12 G550 high-strength cold-formed cold-formed thin-walled Z-shaped steels were subjected to bending tests in the form of oblique curling, straight curling and complex crimping. The parts were statically tested. The test results show that the curling form has a significant influence on the buckling mode and flexural bearing capacity of the specimen. The local buckling or distortional buckling of the specimen occurs, and the bearing capacity of the straight crimped specimen is higher than that of the oblique crimping specimen. The bearing capacity and the bearing capacity of the complex type II crimped specimens are higher than those of the complex type I crimped specimens. Based on the test results and in combination with the existing foreign direct strength formulas, the formula for correcting the direct bearing strength of the G550 high-strength cold-formed thin-walled Z-bending steel flexural members in localized and distorted related buckling deformations is regressed, when such components are distorted. When buckling, there is no need to modify the existing direct strength formula. The finite element model was established to analyze the test. The analysis results were in good agreement with the test results. Based on this, using a large number of finite element analysis results to verify the direct strength method modified formula is more secure and reliable than the existing direct strength method formula for the prediction of the bearing capacity of such components.