Citation

Hutchinson TP. J. Biomech. Eng. 2013; 135(11): 114508.

Copyright

(Copyright © 2013, American Society of Mechanical Engineers)

DOI

10.1115/1.4025331

PMID

24008426

Abstract

Background. Impact testing of pedestrian headforms is usually conducted at one velocity and with one mass of headform, but real impacts occur at a range of velocities and masses. A method is proposed to predict the Head Injury Criterion (HIC) and similar quantities at other velocities from their values observed under test conditions. Method. The assumption is made that force during the impact is proportional to (x^c).[1 + (b/v)x?]. (The notation used is x = displacement, its differential x? = instantaneous velocity, m = mass of headform, and v = initial velocity.) This represents a spring that is nonlinear if c is not 1, with damping if b is not 0. This equation is not solved, but some properties of the solution are obtained. Results. It is shown that HIC is proportional to (m^p).(v^q), where the exponents are p = -1.5/(c+1) and q = (4c+1)/(c+1). Conclusion. Simple formulae are obtained for the dependence of HIC, maximum acceleration, and maximum displacement on velocity and mass. These are relevant to many types of impact.

Language: en