Browsing by Author "Sheldon, Robert Philip"
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Item Open Access Cranfield University centre of excellence in counter-terrorism(2018-10-04) Forth, Shaun A.; Johnson, Stephen; Burrows, Stephanie J.; Sheldon, Robert PhilipThe formation of Cranfield University’s Counterterrorism Centre of Excellence was announced in late summer 2017. It has been established in conjunction with Pool Re, a mutual reinsurer which underwrites over £2 trillion of exposure to terrorism risk in the UK. The centre will provide thought leadership in catastrophic and unconventional terrorism loss assessment and mitigation so as to improve the UK’s economic resilience. We introduce the reinsurance industry for a technical audience to explain the rationale for the Counterterrorism Centre of Excellence. The centre’s aims and some results from preliminary simulations on explosive blast in a complex city centre performed in collaboration with reinsurance broker Guy Carpenter are presented. The prospects for physics-based simulation, for terrorist insurance loss estimation and for encouraging mitigation in reinsurance are outlined.Item Open Access Partial validation of CFD blast simulation in a cityscape environment featuring structural failure(WIT Press, 2021-06-24) Burrows, Stephanie Jeanne; Forth, Shaun A.; Sheldon, Robert PhilipWe demonstrate the capabilities of computational fluid dynamics (CFD) and a pressure-impulse failure model to predict blast loading and structural damage in a geometrically complex cityscape. The simulated loading is compared against experimental results for 69 g PE4 in a 1/50th scale model with wood-framed and plywood-faced buildings; data were collected from 11 pressure gauges throughout. In the initial simulation, geometric features were modeled as perfectly rigid, whereas buildings in the experiment failed: the resulting differences between the model and experiment allowed us to evaluate CFD when failure occurs. Simulated peak pressures during the first positive phase were still within 20% of experiment at most pressure gauges. However, errors in first phase impulses were around 40%, suggesting that building-failure effects are greater toward the phase end. Then, to model building-failure effects, we attempted to fit pressure-impulse failure curves to the plywood-faces: this proved too simplistic to produce realistic blast wave behavior due to the various, complex failure modes. This work illustrates key limitations of available CFD software and the pressure-impulse fail- ure model – both industry-standard tools to determine structural response to blast. We conclude that stronger coupling between blast loading and structural response is needed where significant failure occurs.