## 5 Conclusions  
The experimental and numerical studies confirmed that the bend radius of the V-structure is an important parameter in the design of blast-mitigating V-hulls for MRAP vehicles. The current work showed that the larger tip-radii structures exhibit plastic deformation over a wider area than the previously tested structures with relatively sharp tips [4; 5], in which a greater proportion of the ridge exhibited permanent deformation. Given that plate deflection is known to strongly correlate with energy-equivalent impulse [37], the experimental measurements confirmed the model's predictions that the initial blast loading would be highly non-uniform and correlated with V-structure geometry.  
None of the V-structures exhibited material rupture for the charge mass range considered, but work by [PERSON] et al. [38] showed for stiffened steel plates that areas of localized deformation are the regions that rupture more readily as charge mass increases. Thus, the regions of high deformation gradient (localized displacements) in the V-structures will be more prone to rupturing if the charge mass is increased beyond the range tested herein.  
Increasing the tip radius while keeping the internal angle constant also increased the global impulse transfer to the V-structure, which may have a deleterious effect on passenger safety in practical use. One limitation of this study was the examination of only one stand-off distance, but the findings herein can be used as validation data for future simulation work of a greater range of threat scenarios (including off-centre blasts).  
This study has implications for deployment of V-structures for blast protection--sharp-tipped V-structures will exhibit less permanent deformation but will be more prone to localized rupture in the areas that do deform, whereas structures with larger tip radii will need a larger region of the V-structure repaired after a blast event but may be less prone to rupture under highly localized blast loads. Given that a rupture would be catastrophic, there may be some optimization of a V-structured tip radius and internal angle required when assessing the range of threats for a deployed MRAP vehicle.  
Conceptualization, G.S.L. and C.J.v.K.; methodology, G.S.L., V.R.S. and C.J.v.K.; validation, V.R.S.; formal analysis, V.R.S.; investigation, V.R.S., G.S.L. and C.J.v.K.; resources, G.S.L.; data curation, V.R.S.; writing--original draft preparation, G.S.L. and V.R.S.; writing--review and editing, C.J.v.K.; supervision, G.S.L. and C.J.v.K.; project administration, G.S.L.; funding acquisition, G.S.L. All authors have read and agreed to the published version of the manuscript.  
This research was funded by National Research Foundation of South Africa, grant number 111737. Opinions expressed and conclusions arrived at are those of the authors and are not necessarily to be attributed to the NRF.  
Not applicable.  
The data presented in this study are available on request from the corresponding author. The data are not publicly available due to this being part of an ongoing PhD study.  
The authors are grateful to the UCT University Research Committee and to SSAB and Vulcan Steel for their donations of Domex steel. The authors would also like to thank the staff of the UCT Mechanical Engineering workshop for their assistance in machining the specimens and test consumables. Computations were performed using facilities provided by the University of Cape Town's ICTS High Performance Computing team: [[https://uchpc.uct.ac.za/](https://uchpc.uct.ac.za/)]([https://uchpc.uct.ac.za/](https://uchpc.uct.ac.za/)) (last accessed on 10 December 2022).  
The authors declare no conflict of interest.