No abstract

Glulam bamboo has been preliminarily explored for use as a structural building material, and its stress–strain model under axial loading has a fundamental role in the analysis of bamboo components. To study the tension and compression behaviour of glulam bamboo, the bamboo scrimber and laminated bamboo as two kinds of typical glulam bamboo materials were tested under axial loading. Their mechanical behaviour and failure modes were investigated. The results showed that the bamboo scrimber and laminated bamboo have similar failure modes. For tensile failure, bamboo fibres were ruptured with sawtooth failure surfaces shown as brittle failure; for compression failure, the two modes of compression are buckling and compression shear failure. The stress–strain relationship curves of the bamboo scrimber and laminated bamboo are also similar. The tensile stress–strain curves showed a linear relationship, and the compressive stress–strain curves can be divided into three stages: elastic, elastoplastic and post-yield. Based on the test results, the stress–strain model was proposed for glulam bamboo, in which a linear equation was used to describe the tensile stress–strain relationship and the Richard–Abbott model was employed to model the compressive stress–strain relationship. A comparison with the experimental results shows that the predicted results are in good agreement with the experimental curves.

A novel bamboo-concrete composite structure with threaded reinforcement connections is presented. Experimental investigations on the shear behavior of the connectors and the flexural performance of the bamboo-concrete composite beams were carried out. The results indicate that the load-slip behavior of the shear connection with threaded reinforcement exhibits good ductility and that its failure mode is ductile failure. The threaded reinforcement provides an efficient connection before the initial shear failure. The load-displacement curves of the bamboo-concrete composite beams are close to those of the full composite structure, and the midspan displacement is greatly reduced under the same load compared with that of the contrast bamboo beams. The loads PL/250 and PL/300, corresponding to the midspan deflections of L/250 and L/300 ( L is the span of the beams) of the composite beams, increase by averages of 3.36 times and 3.71 times, respectively, compared to those of the contrast bamboo beams. The load-bearing performance of the beams in the service state is greatly improved. Based on the equivalent cross-sectional stiffness calculated using the γ-method with a reduction of 0.80, the calculated results of the displacement are in good agreement with the test results.

Deviations in the countersunk hole’s angle and depth affect the strength of the bolted composites under tensile loading. Tolerance of the countersunk hole’s angle and depth could be allocated by the Digital Twin of the bolted CFRP-Metal bolt joint. The paper presents a simulation-based Digital Twin for tolerance allocation of CFRP-Metal countersunk bolt joint, mainly considering the strength of the single bolt countersunk joint. Using the design-of-experiment method, nine numerical models with different hole’s angle and depth are constructed to simulate the countersunk holes with different deviations. Simulation results are input into the Digital Twin of the CFRP-Metal countersunk bolt joint. Analysis of variation (ANOVA) method is employed to deeply investigate the interaction between the angle deviation and the depth deviation under tensile loading. Tolerance of the countersunk hole is allocated based on the proposed Digital Twin involving simulation information. The depth should be more strictly controlled than the angle during the course of countersinking. The reported work enhances the understanding of the tolerance allocation for the bolted joint of the composites, and of the simulation-based Digital Twin for CFRP-Metal countersunk bolt joint.