دانلود رایگان مقاله انگلیسی طراحی مقاوم در برابر آتش در ستون های فولادی ضد زنگ فشرده برون محوری با محدودیت - الزویر 2018

Abstract:

Based on the test results of 7 specimens in fire, the numerical simulation analysis were performed on the fire-resistance performance of the eccentrically compressed stainless steel columns with constraints and the numerical simulation methods were verified. The parametric analysis was carried out to investigate the influence of key factors (such as load ratio, eccentricity, axial constraint stiffness ratio, slenderness ratio, and so on) on the fire-resistance of the eccentrically compressed stainless steel columns with constraints. Based on the existing fire-resistant design methods of unconstrained stainless steel columns, the calculation formula for the buckling temperature of eccentrically compressed stainless steel columns with constraints is proposed, and the relationship between the buckling temperature and failure temperature is obtained. The results show that the fitting formula can better predict the buckling temperature and the post-buckling stage may better improve the fire resistance performance of stainless steel columns. The load ratio, eccentricity and axial constraint stiffness ratio are the key factors that determine the fire-resistance performance of eccentrically compressed stainless steel columns with constraints. The greater the load ratio, eccentricity and axial constraint stiffness ratio, the greater the deviations between the buckling temperature and failure temperature become and the better the fire resistance performance of columns in post-buckling stage. When the slenderness ratio is among 80 - 120, the difference between the buckling temperature and failure temperature is the smallest, and correspondingly, the fire resistance performance of stainless steel column is weakest.

5. Conclusions

Based on S30408 austenitic stainless steel, the numerical simulation analysis and parametric analysis on the fire resistance of eccentrically compressed stainless steel columns with constraintswere carried out, and the buckling temperature and failure temperature of columns in fire were studied. The main conclusions are as follows:  (1) The parametric analysis results show that the load ratio and the axial constraint slenderness  ratio are the external influence factors, and the slenderness ratio and the eccentricity are the internal 5 influence factors on the fire resistance of stainless steel columns with constraints.  (2) The mechanics behaviour of eccentrically compressed stainless steel columns with constraints mainly experiences two stages in fire: the pre-buckling stage and the post-buckling stage. There are  two main failure modes: Failure mode 1 (brittle failure) and Failure mode 2 (ductile failure), which  are occurred in the stainless steel columns with constraints in fire. (3) An implicit formula for the buckling temperature of eccentrically compressed stainless steel columns with constraints is proposed, and the accuracy of the formula is verified by the results of numerical simulation analysis based on the 153 finite element models. (4) The influences of various parameters on the deviation between the buckling temperature and failure temperature were investigated. The relationship between buckling temperature and failure temperature is established to facilitate the fire-resistant design of eccentrically compressed stainless 16 steel columns with constraints. Based on the research results in this paper, further researches on the fire resistant design methods 18 of eccentrically compressed stainless steel columns with constraints and fine constitutive models of 19 stainless steel will be carried out.