Abstract: A substitutive model is no more than one-third the size and weight of the archetypical model as originally built or conceived, hence is more wieldy and affordable, yet yields comparable UNDEX test data. The substitutive model comprises two congruous accordion-like “concertina” components and an intermediate smooth cylindrical sectional hull component. The concertina components each have circumferential pleats, generally describe a cylindrical shape, are coaxially joined with the intermediate hull component, and are thus so configured and arranged as to imbue the substitutive model with underwater explosion response (e.g., flexural) properties which approximate those of the archetypical model.

Abstract: An impact dynamometer is provided to determine a force history that has high and low frequency components. An impact plate receives an impact force at a zone of impact and an accelerometer measures the acceleration of the impact plate at the zone of impact. A plurality of posts, located distally from the zone of impact, support the impact plate and transmit the impact force from the impact plate. One or more accelerometers measure acceleration of the impact plate at the posts. The acceleration measured at the zone of impact and at the posts is indicative of the high frequency components of the impact force. Strain gauges measure the impact force at the posts which is indicative of the low frequency components of the impact force. A spring cushion supports the posts and elastically absorbs the impact force passed through the posts in order to maintain the structural integrity of the impact dynamometer.