Crashworthiness of tapered thin-walled S-shaped structures

•Eighty four thin-walled S-rails with different tapering ratios are studied•Energy Absorption (EA) and Specific Energy Absorption (SEA) variations are examined•An optimized tapering ratio is proposed to achieve the highest SEA in the models•An increase in the tapering ratio results in EA rise in all S-rails•Increasing the tapering ratio raises the SEA in non-reinforced S-rails•Tapering ratio increase has a variable impact on SEA in reinforced S-rails

In a vehicular crash, a higher level of energy absorption in the frontal structures of the vehicle leads to less transferred energy to the passengers and less possibility for injury. S-shaped front rails, also known as S-rails, are one of the main structural elements and energy absorbers in the body of a vehicle. To improve the safety of passengers, the S-rail design should be optimized to absorb higher levels of energy in a frontal crash. In this study, the impact of tapering S-rails on the energy absorption is investigated. Two S-rails, one without internal diagonal reinforcement (type-A) and one with internal diagonal reinforcement (type-B), are both tapered with 20 different tapering ratios ranging from 110% to 300% in 10% increments. All of the S-rail models are subjected to static and dynamic loading conditions. Finite element analysis is used to assess the effectiveness of tapering S-rails by investigating the energy absorption (EA) and specific energy absorption (SEA) variations. An equation is developed to verify the numerical results. In this study, the reinforcing and tapering S-rails are shown to improve the EA and SEA under both static and dynamic loading conditions. By combining reinforcing and tapering techniques, S-rails showed a noticeable improvement in SEA of more than 300% in the static loading condition and an improvement of 275% in the dynamic loading condition.