This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
An Analytical Study on Headform Impact Protection Space for a Rigid Target
Technical Paper
2000-01-0608
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Event:
SAE 2000 World Congress
Language:
English
Abstract
This paper examines the theoretical worst case of normal headform impact on an infinitely rigid surface with the help of a dynamic spring-mass model. It is pointed out that the current approach is not an actual representation of any vehicle upper interior but is useful in gaining insight into the headform impact phenomenon and determining how to further enhance design. After considering force-deflection characteristics of a variety of commonly used headform impact protection countermeasures, a mathematical model is set up with spring properties that approximate those of physical countermeasures. Closed-form solutions are derived for various dynamic elasto-plastic phases including elastic unloading and contact. A parametric study is then carried out with HIC(d) as the dependent variable, and spring stiffness, yield force and spring length (representing countermeasure crush space) as the design variables. Through analysis performed in this study, it will be shown that no matter how efficient a countermeasure may be in terms of energy absorption, a crush space of about 30 mm to cover an infinitely rigid surface is generally required for attaining HIC(d) levels below 1000 at an impact velocity of 15 mph. It is pointed out that in an actual vehicle environment, a crush space of less than 30 mm may suffice due to structural compliance of vehicle targets. The approach detailed here can be extended to this latter case of headform impact targets with finite stiffness and yield characteristics.
Recommended Content
Technical Paper | Effects of Unloading and Strain Rate on Headform Impact Simulation |
Technical Paper | On the Dynamics of a Belt-Tensioner with Dry-Friction and Nonlinear Spring |
Technical Paper | Analysis of Effect of Tensioner on Chain System |
Authors
Topic
Citation
Deb, A., Chou, C., and Barbat, S., "An Analytical Study on Headform Impact Protection Space for a Rigid Target," SAE Technical Paper 2000-01-0608, 2000, https://doi.org/10.4271/2000-01-0608.Also In
SAE 2000 Transactions Journal of Passenger Cars - Mechanical Systems
Number: V109-6; Published: 2001-09-15
Number: V109-6; Published: 2001-09-15
References
- Arimoto, H. Yasuki, T. Kawamura K. Kondou, M. “A Study on Energy-Absorbing Mechanism of Plastic Ribs” Proceedings of the IBEC’98 6 81 90
- Rychlewski H.A. Miller P. M. II “A General Discussion on Interior Design Alternatives in Response to FMVSS 201 U-Upper Interior Head Impact Protection” Proceedings of the IBEC’98 6 91 95
- Naick P.A. Carnago, K. M. “Theoretical Relationship of HIC_d to Crush Space for FMVSS 201 Head Impact Tests, and the Effective Use of FEA in Predicting HIC for Design, Verification and Optimization of Countermeasures” Proceedings of the IBEC’98 6 97 105
- Gandhi, G. Hertema D. Rey, T. “A Statistical Approach to Design Trim Pillars for FMVSS Extended Head Impact” SAE Paper No. 970162
- Sounik, D.F. et al, “Head-Impact Testing of Polyurethane Energy-Absorbing (EA) Foams” SAE Paper No. 970160
- Deb, A. Calso S. Saha, N. “Effectiveness of Countermeasures in Upper Interior Head Impact” SAE Paper No. 970391
- Barbat S.D. Prasad, P. “Finite Element Modeling of Structural Foam and Head Impact Interaction with Vehicle Upper Interior” SAE Paper No. 950885
- Chou, C.C. et al, “Comparative Analysis of Different Energy Absorbing Materials for Interior Head Impact” SAE Paper No. 950332
- Monk M.W. Sullivan, L.K. “Energy Absorption Material Selection Methodology for Head/A-Pillar” SAE Paper No. 861887
- Lim, G.G. Chou, C.C et al, “Estimating the Minimum Space to Meet Federal Interior Head Impact Requirement” SAE Paper No. 950333
- Chou C.C. Nyquist, G.W. “Analytical Studies of the Head Injury Criterion (HIC)” SAE Paper No. 740082
- O-Flex, Inc., 1531 Sarah Court, Murfreesboro, TN 37129
- The Oakwood Group, 1100 Oakwood Blvd., Dearborn, MI 48124