8B. ANALYSIS PART 2

CHAPTER 8B 'ANALYSIS' 78 In the next section "Rayleigh damping" the designer is asked to select the parameter values for the Rayleigh damping register. In particular, the damping coefficient must be defined, as well as the two eigenmodes on which this coefficient will be imposed. Using these parameters the program calculates the values of the coefficients a and b for the Reyleigh damping register. Finally, the duration of the analysis and the time step to be used must be defined. OBSERVATIONS: It should be noted that the time duration and the time step of the analysis do not necessarily have to be the same as in the accelerogram. In the case where the time step of the analysis is shorter than the step of the accelerogram then linear interpolation is performed between the two closest points. In the case in which the time duration of the analysis is longer than the time duration of the accelerogram, then the vector will perform free oscillation for the remaining time. After completing the input of the parameters, the user is returned to the original analysis run window where he can proceed to the next steps.