design and analysis of graded open-cell aluminum foam shock absorber for helicopter seats during emergency landing conditions

Ensuring the safety of passengers as much as possible is essential in automobile and airplane accidents. in this study, an open-cell aluminum foam was introduced as an energy absorber. analytical equations of absorbed energy were extracted. the analytical results had acceptable agreement with numerical and empirical ones. based on the graded nature of natural impact absorbers, graded designed was used for the helicopter seat impact absorber. optimization methods including genetic algorithm and sequential quadratic programming algorithm were used to create an optimum graded impact absorber. satisfying standard requirements of the jar-27 air standard was used as a design goal for impact absorber. the designed impact absorber was then modeled in abaqus software to calculate the absorbed energy, acceleration, and the force applied to the passenger and hic for the protected passenger. according to the results, the graded foam satisfies all requirements for helicopters during emergency landing. the derived analytical equations can be used to study the energy absorption of other foams.