Research The Low-velocity Impact Performance Of Hollow Integrated Core Sandwich Composites

Fiber-reinforced composite materials were widely used in the field of engineering because of their high specific strength and stiffness. For it is more sensitive to impact, one of the major concerns in the use of fiber-reinforced composite materials is the damage induced in these materials by foreign object impacts that are expected during manufacture, usage and servicing. Most of the composite materials have no obvious visual damage when suffered low-velocity impact, but impact induced damage can cause drastic reduction in the strength and stiffness of the structure. For this reason, impact on fiber-reinforced composite materials has been subject of intense research efforts.Hollow integrated sandwich composite is a new kind of 3D-woven sandwich composite and one of fiber-reinforced composites. As domestic markets of hollow integrated sandwich composite are expanded, it is more important to improve the reliability database and theoretical analysis, especially the performance of low-velocity impact.(1)According to the peculiarity and technical requirement of the composite, the drop hammer impact machine was manufactured.(2)The second part of this thesis study the low-velocity impact response and residual compressive properties of integrated hollow core sandwich composites panels with different core heights, as the impact energy and parameter of integrated hollow core sandwich composites being equal. The impact parameters, such as peak load, time to peak load, load and absorbed energy as functions of time, and residual compressive strength were calculated.(3)The third part of this thesis study the low-velocity impact response and residual compressive properties of integrated hollow core sandwich composites panels at different impact energies, when the parameters of integrated hollow core sandwich composites are same. The impact parameters, such as peak load, time to peak load, load and absorbed energy as functions of time, and residual compressive strength were calculated.(4)Considering the face of integral hollow core sandwich is very thin and weak in sustaining low-velocity impact loading, in this part, the face sheets were strengthened by using aluminum skin. It was investigated that the low-velocity impact performance of hollow 3-D integrated core sandwich composite with and without aluminum skin such as load , absorbed energy as functions of impact energyThrough research and analysis of this issue, it was evaluated that the condition of impact load, absorbed energy as a function of time and the low of impact damage, while comprehending detailed the performance of low-velocity impact and failure process. It lays a good foundation of further research.