This work mainly investigates the effects of the hole number and layer direction on the tensile mechanical behavior and failure mechanisms of multihole fiber metal laminates by experimental and numerical methods. With the aid of digital image correlation technique, tensile tests are implemented to obtain mechanical responses of different multihole fiber metal laminates. Subsequently, numerical simulation considering thermal residual stress is conducted to elucidate the failure modes and progressive damage evolution of multihole fiber metal laminates, which integrates the progressive damage model of composite laminates and a cohesive zone model between aluminum sheet/composite laminates. Finally, numerical predictions are found in a good agreement with experimental measurements, in terms of mechanical responses and fracture morphologies. Results demonstrate that the number of holes has negligible influence on the ultimate tensile strength, whereas affects the final failure strain of multihole fiber metal laminates evidently. With the increase of layer direction, the fracture morphology changes from evident brittle fracture to fiber pull-out and matrix damage, which indicates that the critical failure mechanism of multihole fiber metal laminates changes from tension dominated to tension–shear dominated. Additionally, the longer loading history from initial damage to final failure of composite laminates demonstrates the significance of considering progressive damage behavior in numerical simulation.

The moisture diffusion behaviors of 3D woven composites exhibit non-Fickian properties when they are exposed to a hydrothermal environment. Although some experimental works have been undertaken to investigate this phenomenon, very few mathematical works on non-Fickian moisture diffusion predictions of 3D woven composites are available in the literature. To capture the non-Fickian behavior of moisture diffusion in 3D woven composites, this study first utilized a time fractional diffusion equation to derive the percentage of moisture content of a homogeneous material under hydrothermal conditions. A two-stage moisture diffusion model was subsequently developed based on the moisture diffusion mechanics of both neat resin and 3D woven composites, which describes the initial fast diffusion and the long-term slow diffusion stages. Notably, the model incorporated fractional order parameters to account for the nonlinear property of moisture diffusion in composites. Finally, the weight gain curves of neat resin and the 3D woven composite were calculated to verify the fractional diffusion model, and the predicted moisture uptake curves were all in good agreement with the experimental results. It is important to note that when the fractional order parameter α < 1, the initial moisture uptake will become larger with a later slow down process. This phenomenon can better describe non-Fickian behavior caused by initial voids or complicated structures.

The recycling of construction waste is key to reducing waste generation and CO₂ emissions. This study aimed to develop a quantitative model for analyzing the carbon reduction potential of recycling construction, demolition, and renovation waste (CDRW) in Jiangsu province. The waste generation rate calculation method and nonlinear autoregressive artificial neural network model were used to estimate and predict CDRW generation. The life cycle assessment was performed to calculate the carbon reduction potential of recycling CDRW. In quantifying the carbon reduction potential, not only construction and demolition waste, but also renovation waste was considered for the first time. The results showed that the total carbon reduction potential of recycling CDRW increased from 3.94 Mt CO₂e in 2000 to 58.65 Mt CO₂e in 2020. Steel and concrete were the main contributors. By scenario analysis, the carbon reduction potential of fully recycling CDRW in 2020 increased by 37.79 Mt CO₂e, a growth rate of 64%. The study further predicts future CDRW generation and the corresponding carbon reduction potential. Our conclusions indicate that 245.45 Mt of CDRW will be generated in 2030, and carbon reduction potential may reach 82.36 Mt CO₂e. These results will help the government manage construction waste better and reach early achievement of the carbon peak target.