2018 Volume 4 Pages 17-00441
Deployable structures are necessary for spacecraft to challenge advanced missions. It is important in designing the deployable space structures that they are easily deployable and reliably repeatable. Conventional study for improving the repeatability was conducted by investigating errors and its effect to the deployment. However, there was no general numerical method to evaluate the reliability efficiently and quantitatively, not estimating any errors. Therefore, the authors proposed an original numerical method to evaluate quantitatively the reliability of the deployment by detecting buckling in a dynamic analysis of FEM in 2016. In the recent study, we found a problem of false detection of the buckling by the conventional method, and we also found a method to solve the problem. The conventional method to detect the buckling in the dynamic analysis uses mode orthogonality to the rigid-body modal space and the eigenvalue. However, it was confirmed that the rigid-body mode is not discriminated correctly for the mixed modes of the rigid-body motion and the deformation. The cause of the problem is using the eigenvalue for the judgement of the buckling because it cannot be evaluate that the sign of the eigenvalue derives whether from the rigid-body motion or from the deformation. Therefore, this study proposes a modified method, not using the eigenvalue but using the work of the deformation for the judgement of the buckling. Finally, it was confirmed that the modified method enabled proper detection of the buckling for the mixed modes of the rigid-body motion and the deformation.