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This paper presents the results of an experimental study of the fatigue and fracture behavior of Bambusa Vulgaris-Schrad bamboo. Mechanisms of crack initiation and growth are elucidated under monotonic and cyclic compressive failure or flexural loading. The microscopic studies of fatigue and fracture explore the effects of fiber/crack/ply orientation on crack growth and toughening mechanisms in single-edge notched and double -edge notched fracture mechanics bend specimens, which are studied in the “crack-arrestor” and “crack-divider” orientations. The compressive fatigue behavior of Bambusa Vulgaris-Schrad bamboo is also investigated in smooth un-notched specimens. The resulting stress-life behavior is shown to occur in a regime in which the maximum stresses exceed the critical conditions for the onset of progressive fiber buckling and shear band formation. This results ultimately in the nucleation and propagation of interlaminar cracks and shear cracks across the Bambusa Vulgaris-Schrad structures. The implications of the results are discussed for the design of robust bamboo structures.

This paper presents the results of a combined experimental and theoretical study of the interfacial and mechanical properties of epoxy/clay composites coatings on a mild steel substrate. This was studied using nano-indentation and Brazil Disk techniques to determine the Young’s moduli, hardness values and mode mixity characteristics of the composite coatings. The Young’s moduli of the reinforced composites comprising 1, 3, and 5 wt. % of montmorillonite clay particles are shown to improve, respectively, by about 23%, 58%, and 50% while the respective hardness values increased by about 46%, 80%, and 88%, relative to those of pristine epoxy. The measured mechanical properties have also shown to compare favorably with predictions from composite theories (rule-of-mixture and shear lag theories). The interfacial toughness between X65 steel and the epoxy/clay coatings increases with increasing mode mixity. This is associated with crack-tip shielding by crack deflection and crack bridging. The trends in the measured mode-mixity dependence of the interfacial fracture toughness values are consistent with predictions from the simplified zone, normal zone, and row models (at lower mode mixity). The insights from the observations and the measured crack profiles are incorporated into zone and row models for the estimation of crack-tip shielding. The implications of the results are discussed for the design of epoxy/clay composites with attractive combinations of mechanical properties.