نوع مقاله : مقاله پژوهشی
عنوان مقاله English
نویسندگان English
In this paper, the displacement response of a nonlinear softening two-degree-of-freedom system under a range of sinusoidal loadings with different frequencies and force amplitudes has been investigated. The stiffness changes of this system had a quadratic relationship with the displacement value. Eight numerical methods including the 3rd-order acceleration method, the 2nd-order acceleration method, the Newmark method (linear acceleration method), the Newmark method (average acceleration method), the Wilson-Theta method, the central difference method, the Jennings method and the innovative method were used to calculate the displacement response of this system. Using the innovative method and using t∆ equal to 0.001 seconds, the displacement response of the system was calculated and was considered as the exact response of the system. Then, for t∆s of 0.001, 0.002, 0.003, 0.004, 0.005, 0.006, and 0.007, and using the 8 numerical methods introduced above, the displacement response of this system was calculated for PGAs of 1, 2, 3, 4, and 5 meters per second squared, and the values of the root mean square error and the coefficient of variation of the error of these 8 methods were calculated for the t∆s defined above. The results of the work are presented in the form of bar graphs in the article.
کلیدواژهها English
