Effects of Loading Direction and Strain Rate on Mechanical Properties and Failure Modes of Teak

The mechanical response and failure mode of wood under compressive load are of great significance for structural design and integrity evaluation. The stress–strain curve of teak with strong impact resistance was investigated by compressive experimenting in the axial, tangential and radial directions under wide strain rates from 10–3 to 103. The results show that their responses behaves similarly and presents a three-stage characteristics in the same loading direction. Teak strength are distinctly directional and strain rate dependent. Deformation processes are monitored by a high-speed camera, which demonstrates that the failure modes consist mainly of fracture, buckling and separation of fiber bundles, crushing, buckling and delamination of the annual ring layer. They are confirmed by the microstructural results. Besides, the failure modes are also affected by the loading direction and strain rate.