The number of present times of input parameters is either proportional to value of the corresponding membership function or to the value of the probabilistic density function. A method for determining the appropriate combination of deterministic inputs so that each input parameter will present only one time in each combination is proposed. To illustrate the proposed method, an example on the determination of input combinations of tornado's velocity in Vietnam is presented. | Vietnam Journal of Mechanics, VAST, Vol. 29 , No. 2 (2007) , pp . 117 - 126 FORMULATION OF THE MEMBERSHIP FUNCTION AND DETERMINATION OF THE INPUT OF FUZZY LOADS IN THE STRUCTURAL FUZZY ANALYZING PROBLEM NGUYEN VAN PHO Hanoi University of Civil Engineering Abstract. The fu zzy analyzing process consists of different steps. In this paper, the author considers only the method for formulation of the membership function of fuzzy loads acting on the structure. Based on the membership function of fuzzy loads, the combinations of deterministic of the regression analyzing process will be determined . The membership function of fuzzy loads is selected by the triangular membership funct ion. It is in conformity with the concept on selection of loads in the design standards. The combination of inputs for thEt analyzing process will be determined, based on the number of present times of the value of input parameters (including the deterministic parameters, fuzzy parameters and the random ones) in the schema of analysis . The number of present times of input parameters is either proportional to value of the corresponding membership function or to the value of the probabilistic density function. A method for determining the appropriate combination of deterministic inputs so that each input parameter will present only one time in each combination is proposed. To illustrate the proposed method, an example on the determination of input combinat ions of tornado's velocity in Vietnam is presented . 1. INTRODUCTION In the structural fuzzy analyzing problem, the deterministic parameters, fuzzy parameters and the random ones are often simultaneously present. More details about the uncertainty parameters taken into account in structural analysis are presented in the references [1 , 2, 3, 4, ]. Structural fuzzy analysis is done according to the following schema [4] - The input of the analyzing process is composed of physical, geometrical and load's parameters . These paramet ers may
