Redesign of dummy impact system test

Sammanfattning

With the need for testing airbags for unbelted passenger crash scenarios, a component test setup was developed to test the passenger side airbags for the USNCAP FFRB 25 mph 50th percentile unbelted load case. This test setup simulates the physics of a frontal vehicle car crash while mimicking the kinematics of a dummy loading into the airbag. Honeycomb (HC) is used to decelerate the sled that holds the dummy interacting with the airbag. Although the HC achieves the deceleration target with a good strength-to-weight ratio, it is plastically deformed and must be discarded after each test. The purpose of this thesis is to find an alternate deceleration feature that can make the test setup configuration repeatable and robust for different load cases, thus broadening the scope of the test setup. A comparative study was conducted on different deceleration features and a damper system proved to be a good alternate to the HC when assessed with design criterias. This damper system was incorporated into the existing Computer-Aided Engineering (CAE) model, which is closely validated to the test setup using the finite element method. This report explores designing a damper with a discrete element feature available in LS DYNA, and parameter studies were conducted to understand the damper behaviour. A simplified model was built that could reproduce the physics of the crash configuration to understand the discrete element characteristic with multiple iterations. Later the finalised damper was incorporated into the full scale CAE model by replacing the honeycomb. The findings of this thesis will be useful to the industry in the future when designing a damper for various load conditions using Finite Element Analysis (FEA) in the LS DYNA platform.