This paper presents a detailed review of the current state of the art in Hopkinson pressure bar (HPB) data analysis. In particular, the underlying theory of the HPB is discussed, and methods of correcting signals for Pochhammer-Chree dispersion and other associated effects are described. The theory of multiple mode propagation is presented, followed by a review of the current methods for correcting multiple mode dispersion, which are especially pertinent when using the HPB as a dynamic force transducer to measure rapidly changing loading events such as explosive blast loads.

Experimental measurements of blast loading using Hopkinson pressure bars are affected by dispersion which can result in the loss or distortion of important high-frequency features. Blast waves typically excite multiple modes of propagation in the bar, and full correction of dispersive effects is not currently possible as the magnitude of stress propagating in each mode is not known. In this paper we develop an algorithm for multiple mode dispersion correction based on rigorous interrogation of the results from a series of finite element analyses. First, a finite element model is validated against first-mode and higher-mode theory. The dispersion of short raised-cosine windowed pulses is then used to isolate the contribution of each propagating mode, enabling a relationship between frequency and modal apportioning of stress to be obtained for the first four propagating modes. Finally, four-mode dispersion correction is successfully applied to an experimental signal using an algorithm based on the derived relationships for modal apportioning. The four-mode results show significant improvement in the capture of high-frequency features over existing first-mode corrections, and demonstrate the potential of this method for the full correction of dispersion in experimental measurements of blast loading.