Nonlinear Finite Element Calculation of Cold Gas Inflator Housing Ultimate Breakage Load 2022-01-0766

For cold gas Inflator, high refinement of ultimate pressure load forecast of inflator housing is one key of Inflator development. For inflator housing hydro-burst test ultimate load calculation, nonlinear finite element software for high precision results. At beginning, the material parameters of inflator housing for simulation is correlated. The FEA material model adopts the stress-strain data from uniaxial tensile experiments. Considering the geometrical nonlinearity resulting from large deformation as well as material nonlinearity from plastic hardening, the whole tensile process from tensile deformation to failure of the specimen is simulated. Numerical results show that the simulation is appropriate to predict the entire deformation process, and simulation results of ultimate tensile load, X-shape distribution of concentrated instability zone, the fracture location and inclined angle all agrees with that of test results.

After finishing the correlation of uniaxial tensile test and getting accurate material parameters of inflator housing, the ultimate breakage load of inflator housing under hydro-burst test is calculated by FEA software. The discrepancy between FEA calculation and real test of inflator housing breakage pressure was 3.6%, and the deformation and failure position of inflator housing were in good agreement with the test results also. At the same time, the change rules of stress and strain in each direction at the key positions of uniaxial tensile test and hydro-burst test are summarized, then a method to judge the fracture strain according to the stress change trend is proposed. The judged fracture strain by the method corresponds to the test results. The simulation and test results show that the analysis method used in this paper can obtain the ultimate failure load and fracture strain of the inflator housing with high precision.