Experimental behavior of cement filled pipe-in-pipe composite structures under transverse impact

• The pipe-in pipe specimen shows enhanced impact resistance compared to hollow pipes.
• The outer pipe contributes significantly to the impact resistance.
• The cement layer restricts effectively the local indentation in the pipe.

This paper investigates the transverse impact performance for ultra lightweight cement composite (ULCC) filled pipe-in-pipe composite structures through drop weight impact tests and numerical simulations in LS-DYNA. Compared to steel hollow pipes, the sandwich composite pipes demonstrate superior impact performance with higher impact resistance, smaller global deformation and local indentation. The outer pipe and its thickness determine directly the impact resistance and the global bending deformation of the composite pipe. The ULCC layer restricts effectively the development of the local indentation. The presence of the inner pipe enhances the confinement to the ULCC material. The numerical simulation predicts closely the impact response for pipe-in-pipe composite specimens during the drop weight impact test.