STRUCTURAL ROBUSTNESS ANALYSIS OF ANISOGRID LATTICE STRUCTURES

The purpose of this paper is to compare the structural robustness of anisogrid composite lattice structures with orthogrid composite structures when subjected to axial compression. Due to multiple redundant load paths the anisogrid structure should have a higher structural robustness in comparison to orthogrid structures. Within the framework of the EU-Project PoLaRBEAR (Production and Analysis Evolution for Lattice Related Barrel Elements under Operations with Advanced Reliability) anisogrid composite lattice structures are investigated in terms of a suitable primary fuselage alternative for aircrafts. The structural energy, the area under the load-shortening curve between several characteristic points such as the ultimate and collapse load, is evaluated using nonlinear FEM simulations in order to assess the structural robustness of anisogrid composite structures. The results indicate an overall higher structural robustness of the anisogrid structures in comparison to the orthogrid structures for different load cases. In addition anisogrid structures seem to be more insensitive to the simulated impact damages than orthogrid structures. As result, an answer is given if the anisogrid structure concept is a suitable design concept for fuselage structures in commercial aircrafts in terms of structural robustness.