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Laminated bamboo composite (LBC) has received a great attention due to its environmental friendly characteristics and excellent physical and mechanical properties, therefore it is necessary to investigate the durability of the LBC material in ambient environment (temperature and relative humidity). In this paper, firstly, LBC materials were manufactured in laboratory. Moisture absorption and thickness swelling kinetics of the materials at different temperatures and relative humidity were investigated. Then effects of ambient environment on mechanical properties were evaluated at three different ambient temperatures (21 °C, 36 °C, and 60 °C) and different moisture contents. It is found that the moisture absorption and the thickness swelling increase with temperature, relative humidity and ageing time before an equilibrium condition is satisfied. Parameters of the diffusion coefficient and the swelling rate increase with the temperature. In addition, there is a significant decrease in mechanical properties of the moisture-saturated specimens compared to the dry ones. And the degradation of the bending property and the compressive strength is found to be a function of the moisture absorption during the initial period and becomes stable as the absorption process approaches equilibrium. Finally, surface erosions are shown by scanning electron microscopy (SEM) after the hydrothermal aging at 60 °C.

The objective of this work was to use a novel 3-D test analysis system for evaluating the mechanical properties of the natural fiber fabric composites under biaxial loads. Composites with three resin matrices (water-based epoxy resin, isocyanate resin, phenolic resin) were investigated, and strain filed were characterized by using the digital speckle correlation. The water-based epoxy resin plate and isocyanate resin plate demonstrated a characteristic of orthotropy and elastoplasticity, while the phenolic resin board revealed linear elastic and brittle-fracture simultaneously at X,Y-axial. Dissimilarities of biaxial load value were related to the orthotropy of composite structure, and load changes in fracture direction had a negative effect on the other directions at breaking moment. The degrees of dropping presented a positive correlation with the load values at rift direction. Under the linear elastic stage, the value of load and average strain at Y-direction were larger than that under X-direction within the same testing area. The strain-filed at X/Y-direction provided by isocyanate and phenolic resin plates illustrated a more smooth change than that of the water-based epoxy resin plate.

To evaluate the mechanical properties of natural fiber fabrics with the characteristic of interweaving between warp and weft direction as well as textile structural composites under complex stress state, it is essential to develop experimental techniques to realize multi-axial testing for large deformation. This work proposes a novel testing device for investigating fiber fabrics and textile composites under multidimensional loads. Accuracy of the system is comparable to the testing diagnostics of the Instron 5808 previously. The homogeneity for different types of cruciforms and different biaxial tensile speeds were investigated. The effects of different loading methods, biaxial (X and Y), and 3-D loading (X, Y, and Z) on the breaking strength of the woven ramie fabric were presented. The displacement-field and shear field for composites with hole were characterized by the digital speckle correlation method.