SHAPE-SIZE OPTIMIZATION OF PLANE TRUSSES WITH DESIGNERS PREFERENCE

This paper describes a new method for shape and member-size optimizati on of a plane truss by using techniques of parametric curves. Descript ion of nodal coordinates as well as cross-sectional areas in terms of Bezier curves enables one to find a smooth optimal truss. The optimal truss is found under the constraints such that all the response strain s to multiple design loads including static loads and earthquake excit ation are within a prescribed range. The objective function to be mini mized is a weighted sum of the total structural mass and the deviation of the shape from the one preferred by the designer The latter is wri tten explicitly in terms of the coordinates of the control points. Sid e constraints are easily incorporated based on the convex hull propert y of the Bezier curve. In the examples, optimal trusses are found unde r single and multiple loading conditions and the characteristics of th e optimal trusses in reference to the weight coefficients are discusse d.