The Experimental Investigation Of Quasi-static And Dynamic Compressive Mechanical Behaviors,Energy-absorbing Capacity And Collapse Mechanism Of The Al Foam

Al foam is a nice energy-absorption or packaging material, so a study of its static and dynamic compressive mechanical behaviors and energy-absorbing capacity means much to the structural design. The closed Al-Cu alloy foam that is a new kind of Al foam material was investigated in this dissertation. Although someone has studied the compressive mechanical behaviors of Al-Cu alloy foam under quasi-static and high strain-rate load conditions, there are few reports about its behaviors during the low or middle speed loading, for example, test results using dynamic testing rig. Among the conventional tubular energy absorbing elements, tubes with Al foam fillers can achieve high stiffness and energy absorption since Al foam has high energy-absorbing capacity. There are many investigations about the static and dynamic compressive mechanical behaviors of the combined tubes with Al foam filler abroad but few domestically.In this dissertation, the static compressive mechanical behaviors of the cylindrical core specimens of the Al-Cu alloy foam and its components—the circular steel tubes with Al foam filler were investigated, and the dynamic compressive behaviors in low or middle speed loading were studied by the experiment of dynamic testing rig for the first time. These results were compared with those of core and component specimens of pure Al foam. Finally, the collapse mechanisms of Al foam with different solid aluminum were compared and analyzed. The main work can be introduced briefly in three parts.1. For the cylindrical core and component specimens of the Al-Cu alloy foam and those of pure Al foam, the quasi-static experiments were carried out to study their static compressive behaviors and energy-absorption capacity, respectively.1) Specific energy was used to value the energy absorption ability of the foam material. By making the specific energy curves of Al-Cu alloy foam for a special range of density, the energy-absorption performance of the material can be compared directly, and much information for the structural design can be obtained.2) For a special range of density, the fitting curves of relative elastic modulus—relative density and those of relative plateau stress—relative density were built in this paper. It was found that good agreement could be achieved if the constants in Gibson's formulas for open cellular materials were revised to the parameters depended on the experiments.3) The static compressive behaviors of components were studied, and the average force of components was calculated based on the revised Hanssen's formulas, then the theoretical results were compared with the experimental results.Combining with the above analysis, the average force of components with Al foam filler can be calculated if the density of Al foam is known. These results can provide valuable information to the engineering.2. The dynamic compressive mechanical behaviors and energy-absorbing capacity of the Al-Cu alloy foam under low or middle speed loading condition were investigated by...