Low–Speed Impact Mechanics and Fragmentation of Wooden Panels: Characterization of Indian Woods

includes bibliographical references

PhD;2024;Centre for Product Design and Manufacturing

Low–speed impact (LSI) of brittle structural panels by rigid bodies causes significant damage, evident in familiar scenarios like the breaking of monolithic and laminated glass panes due to stone pelting, punching a hole on wooden board with nail-hammer impact, and so on. The stress waves and the vibrations radiated from the point of impact cause fracture and fragmentation of the target bodies in addition to local and global deformations. LSI damage and fragmentation, however no less catastrophic, remain the underexplored research areas, thus posing difficulty in modeling. As most studies focus on the fragmentation of hard or stiff targets under high strain rates, such as ballistics and explosions, investigations on dynamic behavior and LSI fragmentation of rather compliant targets of natural origin such as ‘wood’ are limited. Hence, this work presents a comprehensive investigation of the LSI response of wood through experimental, theoretical, and numerical investigations. This work, overall, encompasses the following contributing works: At first, the nondestructive evaluation (NDE) of an Indian wood forms a preliminary exploration of the nature of stress wave propagation and characterization of natural defects to determine the wood quality. Secondly, experimental and theoretical analyses of LSI mechanics and fragmentation of wooden panels are carried out to understand the behavior of these stress waves under impact loading. Finally, numerical and mathematical modeling of LSI fragmentation of glass and wooden plates, respectively, to capture the precursors of catastrophic fragmentation.