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随着温度升高,铝合金的名义屈服强度和弹性模量下降,进而影响其高温下的极限承载力。将这种影响归纳为两个方面:第一,温度升高引起轴心压杆相对长细比的变化,定义温度函数进行描述;第二,温度升高,在相对长细比相同的情况下,引起轴心压杆稳定系数的变化,定义变换函数进行描述。采用某工程中的工字形截面作为典型截面进行有限元计算,确定两类函数的实用计算公式,并引用我国铝合金结构设计规范中的柱子曲线作为常温下的柱子曲线从而近似考虑截面规格类型不同的影响。最后,对文献中97根试件试验结果与有限元结果进行对比,验证有限元模型的正确性;同时,实用计算方法与欧洲规范方法对比表明:该方法与欧规方法同样安全简便地计算出高温下极限承载力,并且200℃之后比欧规方法更接近试验结果。
As the temperature increases, the nominal yield strength and elastic modulus of the aluminum alloy decrease, thereby affecting the ultimate bearing capacity under high temperature. This effect is summarized in two aspects: first, the change of the relative slenderness ratio of the axial pressure rod caused by the temperature increase, the definition of the temperature function is described; secondly, when the temperature is raised and the relative slenderness ratio is the same , Causing changes in the stability factor of the axial strut, the definition of the transformation function to describe. Using the I-shaped cross-section of a project as a typical section for finite element calculation to determine the practical calculation formula of two types of functions, and reference to the column design curve of aluminum alloy structure in China as the column curve at room temperature so as to approximately consider the type of cross-section of different specifications Impact. Finally, the experimental results of 97 specimens in the literature are compared with the finite element results to verify the correctness of the finite element model. Meanwhile, the comparison between the practical calculation method and the European standard method shows that the method is as safe and convenient as the European method High temperature ultimate bearing capacity, and 200 ℃ after the method is closer to the test results than the European rules.