Towards a stress criterion on injury : an example in caudocephalad acceleration.

The usual specification of acceleration (in number of g's) as the injury criterion in the biodynamic response of the human body to vibration and/or shock is quite misleading if not invalid. An injury criterion based on stress (or strain) is proposed and shown to have the potential of deciding where, when and how injury is sustained. An example in pilot ejection is used for illustration.