Effects of Damage Mode on Crack Propagation Pattern in Additively Manufactured Honeycomb Cellular Panel

Planar cellular structure panels are affected by a series of factors, which can produce various types of initial damage within the structure and thus affect the service life as well as the starting point and path of crack propagation. Investigating the effect of different initial damage modes on crack expansion paths and failure modes in additively manufactured honeycomb cellular panel under quasi-static three-point bending load. Experimental tests and finite element simulations are used. The quasi-static three-point bending experiments are conducted by using the CMT5305 universal testing machine, and numerical simulations are carried out by combining finite element analysis software ANSYS Workbench. Two kinds of experimental specimens with prefabricated cracks (PFC) and plastic hinge truncation (PHT) are fabricated by using additive manufacturing technology to simulate the initial damage. The final failure of the specimens includes plastic failure dominated by type-I cracks and brittle failure dominated by type-I and type-II mixed cracks. T-0-60 and C-90-60 specimens have the strongest crack suppression and load-bearing ability. With the increase in load speed, the cracking displacement decreases, and peak load increases. The undamaged (UDD) specimens have the strongest crack suppression ability at loading speeds of 10mm/min and 50mm/min, while the damage mode has little effect on the peak load of the specimens. The damage mode affects the crack initiation point, propagation path and failure mode of the cellular structure, and the model with initial damage will enhance the crack suppression ability at a specific inclination angle. In practical engineering applications, as a load-bearing structure, such as the open beam of a truck, two types of structures, T-0-60, and C-90-60, should be given priority, while avoiding the design of C-0-60 structure. As an energy-absorbing structure, such as the front bumper of a car, the cushioning effect should be enhanced by adjusting the hole direction and the initial damage direction.