Deformation mechanism of porous composite sandwich beam for orthopaedical application under three-point bending

We have recently developed a porous HA/PLCL composite beam as a new scaffold material prospectively used in the field of bone tissue engineering. In this study, a novel sandwich beam structure was newly introduced to improve the bending mechanical properties of the single HA/PLCL beam. The middle HA/PLCL layer with the two-phase porous structure was sandwiched between the top and bottom spongy PLCL layer. It was revealed from the results of three-point bending tests that the bending mechanical properties of the composite sandwich beam were significantly higher than those of the single composite beam with the critical stress and the fracture absorbed energy increased by 381.7 kPa and 851.2 J/m², respectively. The damage mechanism under the bending condition was also examined by SEM, and found to be characterized by the stepwise crack formations including the subsequent cracking in the top, middle and bottom layers. Those crack formations were associated with the ductile and brittle microfractures of PLCL spongy structure and HA frame structure, respectively.