A Tandem Momentum Trap for Dynamic Specimen Recovery During Split Hopkinson Pressure Bar Testing of Cancellous Bone

Abstract

A novel method for dynamic specimen recovery using tandem momentum traps on an otherwise standard split Hopkinson pressure bar, is presented. The method is based on a pair of concentric tubes that are impedance matched to and co-axially aligned with the input bar and arranged to operate sequentially. The tandem momentum traps provide a single specimen loading event, of a predefined intensity and duration, without the need to initially offset the momentum traps from the input bar by accurate preset gaps. The method is relatively simple to set up and operate, which allows for routine specimen recovery during dynamic testing. The operation of the tandem momentum trap is demonstrated by an investigation of the dynamic mechanical properties of soft cancellous bovine bone specimens