A novel dual bionic design for synergistic enhancement of erosion resistance and mechanical properties of pipe bends

As a common transport device, pipelines are permanently subjected to pressures generated by external loads and to the erosive effects of the substances transported inside. The addition of structures to the inner surface of the pipe has been demonstrated to enhance its strength and erosion resistance to a certain extent. In this paper, a novel bionic model is innovatively proposed using a leaf blade as a bionic prototype. It involves the leaf vein structure on the surface of the leaf blade and the growth arrangement law of the leaf blade (phyllotaxis-arrangement). A series of rigorous gas‒solid erosion tests and compression tests were carried out on a 90° elbow pipe. The effects of the arrangement location (entrance, elbow), arrangement mode (uniform, interlaced, and phyllotaxis), phyllotactic coefficient, and vein fractal angle (30°, 45°, and 60°) on the erosion resistance and compression capacity of the bionic model and pipe were also analyzed. The test results demonstrate that, in comparison with standard bends, the dual bionic bends exhibit a maximum increase in erosion resistance of 41.1% and a maximum increase in compression resistance of 88.6%. The optimum erosion and compression resistance of the bionic model were obtained when the leaf vein fractal angle was 60°. To investigate the synergistic lifting principle of different bionic models, numerical simulation techniques were used to analyze the flow–solid coupling state inside the pipe, the resistance lifting inside the pipe, and the stress of the pipe when it was subjected to external loads. This study provides new ideas in the field of bionic erosion resistance and shows great potential for practical applications.