Optimum Design Of Steel Roof Truss Based On Reliability

In this paper the structural optimum design methods based on reliability are researched systematically. At first, the uncertain factors in engineering are discussed, which declared the importance and necessity of the optimum design based on reliability for structure. Then the calculation of the reliability of structure's elements is discussed against the situation of that some design variables are definite quantity and the design parameters are random quantity. And we extracted that we can establish the optimum mathematical model make use of that the reliable index is the minimum distance from zero to failure interface, and then the reliable index is got. The analogue and the calculation of structured systems' reliability are discussed.The conception and algorithm of optimum design and the basic theory of the full stress design is introduced. The differences between the classical optimum design and the optimum design based on reliability are found by researching a case of three-bar statically indeterminate truss. A method that "the planning solution" is used to solve the definite optimum problem is recommended. Introducing the approximate algorithm of the structured systems' reliability, and combining the basic theory of full-stress design, the optimum iterative guide rule and an effective iterative formula that can accelerate the rapidity of convergence is created. At last, a case about a steel roof truss is used to prove the validity and superiority of the algorithm that is extracted before.