Numerical and experimental study of Polyurethane foam used as core material in sacrificial cladding for blast mitigation

The increase of the number of intentional and accidental explosions nowadays, explains the interest in the development of suitable blast mitigation systems. One technique uses sacrificial cladding (SC) which is composed of polyurethane (PU) core and two thin metallic sheets. For numerical prediction of the effectiveness of SC for blast mitigation, the dynamic material response is needed. Different material models are available in finite element software, such as for example in LS-DYNA. The present paper focuses on an experimental study of the dynamic behaviour of PU under blast loading and on a comparison of the results of numerical blast mitigation predictions.
Dynamic material response of PU subjected to blast loading is investigated; the effect of strain rate is studied. An Explosive Driven Shock Tube (square section) is used to produce given pressure-impulse combinations. By means of a high speed camera and a load cell sensor, the stress-strain curve is obtained during the loading process for several strain rates. Numerical analysis is also performed with the Fu Chang foam model (MAT_083) which is available on the finite element software LS-DYNA. The numerical model is validated with the experimental results. The spatial distribution of the reflected pressure on the front plate should be taken into account. An enhancement of the transmitted stress to the main structure is observed in some critical combinations (front plate and PU). An adequate SC configuration can be identified using the obtained numerical model.

Publication year:2015

Keywords:Sacrificial cladding, Explosive Driven Shock Tube, Polyurethane, Numerical material model, High speed camera