Interior Head Impact Research Articles

Interior Head Impact Analysis of Automotive Instrument Panel for Unrestrained Front Seat Passengers

This study presents the numerical and experimental interior head impact analysis of automotive instrument panel according to the United Nations Economic Commission for Europe Regulation 21 (ECE R21). To minimize the possible injury risk for unrestrained front seat passengers due to the interior head impact with the instrument panel, the panel design needs to meet the ECE R21 standard which defines a pendulum-type head form as the impactor. The measured acceleration response of the head form should not exceed 80g continuously for more than 3ms. Motivated by the need to develop a simulation-based technique to evaluate the design of the instrument panel, a numerical model based on the explicit dynamic finite element analysis (FEA) by using the commercial FEA solver, LS-DYNA, is developed. To minimize the experimental cost, a gravity-based impactor with a smaller impact speed is develop as the test apparatus for verification purpose. The simulated results agree well with the experimental data; the average accuracy for the maximum value of impact acceleration at the head form is 95.4%. After the verification, the standard test conditions (with higher impact speed) are performed to evaluate the design. The outcome of this study can provide an efficient and cost-effective method to predict and improve the design of the instrument panel for interior head impact protection.

HIC(d) and Its Relation With Headform Rotational Acceleration in Vehicle Upper Interior Head Impact Safety Assessment

HIC(d) and Its Relation With Headform Rotational Acceleration in Vehicle Upper Interior Head Impact Safety Assessment

Evaluation of safety of helmets using a featureless Hybrid III headform

This paper proposes a new procedure for designing helmets for head impact protection to road users such as two-wheeler riders and pedestrians. The new procedure suggests that a helmet be mounted on a featureless Hybrid III headform that is used for assessing upper interior head impact safety specified in the vehicle safety standard FMVSS 201 in the USA. To ascertain a helmet's effectiveness as a countermeasure for minimising the risk of severe head injury, an impact velocity of 6 m/s (13.5 mph) was used for the helmet-headform system striking a rigid target. The resultant head impact response is measured by Head Injury Criterion (HIC). The threshold HIC(d) limit of 1000 is applied for adjudging the efficacy of helmets. The proposed procedure is demonstrated with the help of a validated LS-DYNA model of a featureless Hybrid III headform and a helmet. The helmet model consists of an outer General Electric (GE) plastic-based shell to the inner surface of which is bonded a protective energy-absorbing foam padding of a given thickness. Based on simulation results of impact on a rigid surface, it appears that foam padding of suitable strength and a minimum thickness of 35–40 mm along with a shell thickness of 3–4 mm is necessary for obtaining an acceptable value of HIC(d), and therefore, an acceptable helmet safety design.

Roof-Crush Strength Improvement Using Rigid Polyurethane Foam

Recent bending tests show the effectiveness of rigid, polyurethane foam in improving the strength of automotive body structures. By using foam, it is possible to reduce pillar sections, and to reduce thicknesses or eliminate reinforcements inside the pillars, and thereby offset the mass increase due to the foam filling. Further tests showed that utilizing the foam filling in a B-pillar to reduce section size can save ~20 mm that could be utilized to add energy absorbing structures in order to meet the new interior head impact requirements specified by the federal motor vehicle safety standards (FMVSS) 201 Head Impact Protection upgrade.