Post necking material testing, characterization and constitutive modelling

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The National Highway Traffic Safety Administration, Department of Transportation (Federal Motor Vehicle**Safety Standards, FMVSS 206) requires that certain safety considerations and requirements are met in the**design of vehicle components including doors and door locks during rear and side impact. Some of the main**design considerations to protect vehicle occupants are to minimize the impacted force by means of energy**absorption and/or energy diversion. This includes collapsing structural members and foam filled structures, and**snapping safety locks, among others.**The objective of the proposed study is to understand the underlying mechanics of metallic materials under**failure specifically post-necking regime. This includes studying the effect of material microstructure, strength,**hardening and heat treatment on the onset of necking for which available data is limited in the literature and**industry. This will be achieved through developing an integrated test plan, material characterization and**modeling techniques to predict such phenomena. Due to the unique localized non-uniform deformation in the**necking regions, advanced strain measurements using digital imaging will be used. The test results will then be**used to develop constitutive plastic models able to capture the necking behavior. This will be achieved using**two numerical models. The first is an iterative plastic model with updated hardening coefficients and the**second using a porous plastic model with void nucleation.**The proposed study will serve as a backbone of the engineering design and aid in the development, selection**and optimization of more reliable materials and designs, benefiting a wide range of applications. This tool**would, therefore, be an added value to the body of knowledge and offer an effective tool towards innovative**engineering to the Canadian industry.