Experimental study on the energy absorption of porous materials filled with magneto-rheological fluid

In order to achieve adaptive energy absorption, a controllable energy absorbing material was developed by filling magneto-rheological fluid into the porous materials. By means of MTS testing system and nylon split Hopkinson pressure bar, the compression behaviors and energy absorption characteristics of this material under different strain-rates and magnetic field intensities were studied. The results show that without magnetic field, the quasi-static compression behaviors of the materials make no differences with the porous materials without MR fluids, while subjected to magnetic field their energy absorption could be greatly increased. When the magnetic field intensity reaches 0.3T, their quasi-static energy absorption could be increased by about 50%. On the other hand, under impact loadings, the materials without MR fluid exhibit nearly no strain-rate effect. After filled with MR fluid, its strain-rate effect becomes very remarkable. As the compressive strain rate reaches 1500(1/s), its energy absorption could be increased by about two times. It was found that there are three energy dissipation mechanisms which are the skeleton deformation, viscous flowing of MR Fluid and magneto-rheological effects, respectively. With the increase of strain-rate, the viscous flowing effect increases, but the skeleton deformation and magneto-rheological effect do not change, which results in its controllability becomes weaker as the strain-rate increases.