Section optimization design of reticulated dome to ensure constant stability

Key words:  latticed dome  robust critical-limit load  section optimization  imperfection sensitivity  group method

Abstract:

Single-layer latticed domes belong to structures of imperfection sensitivity. In order to decrease the sensitivity of critical-limit load to the initial geometric imperfection, an optimum design method based on the robust critical-limit load requirement is proposed. The lightest fluctuation of bearing capacity to imperfections is taken as the objective function. We group structural members together according to the sensitivity area of imperfection. The sequence two-stage algorithm is adopted to perform the section optimization design. The structural strength, stiffness, overall stability of double nonlinearity, and initial geometric imperfections are considered as constraints. The optimization results show that, compared with the structures that have not been optimized,the average value of critical-limit loads of optimized structures under 28 imperfections is bigger, and the standard deviation, i.e. the fluctuation of critical-limit loads is smaller. This kind of optimum design can make critical-limit loads of optimized structures possess pretty robustness, and decrease the sensitivity of critical-limit loads to imperfections. At the same time, the consumption of steel was economized.