Nonlinear technique of prestressing spatial structures

One of the crucial aspects of the design of structural space systems is the degree of prestressing since it is involved in the load transferring, deformability and charges. The prestress state can be reached via required member alteration. This paper presents an efficient nonlinear numerical approach based on the force method for prestressing the spatial nonlinear structures to the desired level through computing nonlinear actuation as a function of external nodal displacements. Two equations are derived for indicating the required amount of member alteration eo and prestressing level by using Taylor's series and Pade approximation methods. This technique can be applied to both rigid and flexible spatial structures. The present technique is validated based on three numerical examples, and the computational findings are in well agreement with the compared methods. The results show that the new approach requires less effort and makes greater economic sense. Moreover, the member forces with concern to nonlinear eo of double-layer space grid structure by imposing lack of fit of some members successfully obtained.

Automated summary

This paper presents an efficient nonlinear numerical approach based on the force method for prestressing spatial nonlinear structures to the desired level. Two equations are derived for indicating the required amount of member alteration and prestressing level using Taylor's series and Pade approximation methods. The technique is validated based on three numerical examples, showing good agreement with compared methods. The new approach requires less effort and is more economical, while successfully obtaining member forces under lack of fit conditions for a double-layer space grid structure.