FUZZY ARITHMETIC AND SOLVING OF THE STATIC GOVERNING EQUATIONS OF FUZZY FINITE ELEMENT METHOD

The key component of finite element analysis of structures with fuzzy parameters, which is associated with handling of some fuzzy information and arithmetic relation of fuzzy variables, was the solving of the governing equations of fuzzy finite element method. Based on a given interval representation of fuzzy numbers, some arithmetic rules of fuzzy numbers and fuzzy variables were developed in terms of the properties of interval arithmetic. According to the rules and by the theory of interval finite element method, procedures for solving the static governing equations of fuzzy finite element method of structures were presented. By the proposed procedure, the possibility distributions of responses of fuzzy structures can be generated in terms of the membership functions of the input fuzzy numbers. It is shown by a numerical example that the computational burden of the presented procedures is low and easy to implement. The effectiveness and usefulness of the presented procedures are also illustrated.

PROCEDURE FOR COMPUTING THE POSSIBILITY AND FUZZY PROBABILITY OF FAILURE OF STRUCTURES

Traditionally, the calculation of reliability of fuzzy random structures is based on the well-known formulation of probability of fuzzy events. But sometimes the results of this formulation will not indicating the real state of safety of fuzzy-random structures. Based on the possibility theory, a computational procedure for the reliability analysis of fuzzy failure problems and random-fuzzy failure problems of mechanical structures that contain fuzzy variables were presented. A procedure for the analysis of structural reliability of problems of fuzzy failure criterion was also proposed. The failure possibility of fuzzy structures and possibility distribution of the probability of failure of fuzzy-random structures can be given by the proposed methods. It is shown that for the hybrid probabilistic and fuzzy reliability problems, the probability of failure should be suitably taken as a fuzzy variable in order to indicate the real safety of system objectively. Two examples illustrate the validity and rationality of the proposed methods.

Influence of Long-term Climate on Fatigue Life of Bridge Pier Concrete and a Reinforcement Method

This paper quantitatively evaluated the fatigue life of concrete around the air-water boundary layer of bridge piers located in inland rivers,considering the long-term climate.The paper suggests a method to predict the low-cycle fatigue life by demonstrating a thermal-fluid-structural analysis of bridge pier concrete according to long-term climate such as temperature,velocity and pressure of air and water in the process of freezing and thawing in winter.In addition,it proposes a reinforcing method to increase the life of damaged piers and proves the feasibility of the proposed method with numerical comparison experiment.

INTERVAL ARITHMETIC AND STATIC INTERVAL FINITE ELEMENT METHOD

When the uncertainties of structures may be bounded in intervals, through some suitable discretization, interval finite element method can be constructed by combining the interval analysis with the traditional finite element method (FEM). The two parameters, median and deviation, were used to represent the uncertainties of interval variables. Based on the arithmetic rules of intervals, some properties and arithmetic rules of interval variables were demonstrated. Combining the procedure of interval analysis with FEM, a static linear interval finite element method was presented to solve the non-random uncertain structures. ne solving of the characteristic parameters of n-freedom uncertain displacement field of the static governing equation was transformed into 2 n-order linear equations. It is shown by a numerical example that the proposed method is practical and effective.

The Double-ended 750nm and 532nm Laser Output from PPLN-FWM

We investigate 750 nm and 532 nm dual-wavelength laser for applications in the internet of things.A kind of optical maser is developed,in which the semiconductor module outputs the 808 nm pump light and then it goes into a double-clad Nd^(3+):YAG monocrystal optical fiber through the intermediate coupler and forms a 1064 nm laser.The laser outputs come from both left and right terminals.In the right branch,the laser goes into the right cycle polarization LinNbO3(PPLN)crystal through the right coupler,produces the optical parametric oscillation and forms the signal lightλ_(1)(1500 nm),the idle frequency lightλ_(2)(3660.55 nm),and the second-harmonic of the signal lightλ3(750 nm).These three kinds of light and the pump lightλ4 together form the frequency matching and the quasi-phase matching,then the four-wave mixing occurs to create the high-gain light at wavelength 750 nm.Meanwhile,in the left branch,the laser goes into the left PPLN crystal through the left coupler,engenders frequency doubling and forms the light at wavelength 532 nm.That is to say,the optical maser provides 750 nm and 532 nm dual-wavelength laser outputting from two terminals,which is workable.