CFRP （carbon fiber reinforced plastics） composite materials have wide applicability because of their inherent design flexibility and improved material properties. However, impacted composite structures have 50%-75% ...CFRP （carbon fiber reinforced plastics） composite materials have wide applicability because of their inherent design flexibility and improved material properties. However, impacted composite structures have 50%-75% less strength than undamaged structures. In this work, a CFRP composite material was nondestructively characterized in order to ensure product quality and structural integrity of CFRP and one-sided pitch-catch technique was developed to measure impacted-damaged area by using an automated-data acquisition system in an immersion tank. A pitch-catch signal was found to be more sensitive than normal incidence backwall echo of longitudinal wave under defect conditions in the composite.展开更多
Effects of environment conditions, such as current, wave etc., are more important for immersed tube tunnel's transportation and immersing. The hydrodynamics and stability of immersed tube tunnel during its towing ...Effects of environment conditions, such as current, wave etc., are more important for immersed tube tunnel's transportation and immersing. The hydrodynamics and stability of immersed tube tunnel during its towing and immersing are interested for departments of design and construction. A serial model tests are made in towing tank and water channel for Nanjing immersed tube tunnel, and the first immersed tunnel has been designed in Yangtzi River in China. The hydrodynamic forces and rope tensions of the tunnel are measured with strain balances when it is towed by ship and immersed by winches for a different current velocity and wave height. In addition, the stability of tunnel for a different ballast water is tested and discussed.展开更多
A numerical model to predict the hydrodynamic performance of a shoreline-mounted wave energy converter, normally referred to as Oscillating Water Column (OWC), was established. Based on the 3D boundary integral equati...A numerical model to predict the hydrodynamic performance of a shoreline-mounted wave energy converter, normally referred to as Oscillating Water Column (OWC), was established. Based on the 3D boundary integral equation method, the 3D Green's function was utilized to describe the hydrodynamic flow around the device. Using geometrical data of a wave absorber device symmetrically placed in a channel with various barrier depths, the hydrodynamic efficiencies were calculated for regular waves. The results were then compared with analytical results published elsewhere Malmo[8]. And the comparison is shown to be good, thus validating the proposed numerical model. Furthermore, extensive experiments were also made in a wave tank with a 1:12 scale model of an OWC device of different geometrical configurations. The experimental measurements were compared with calculations using the newly developed numerical model. The comparison, which is also shown to be satisfactory, provides further support of the correctness and the accuracy of the numerical method presented.展开更多
文摘CFRP （carbon fiber reinforced plastics） composite materials have wide applicability because of their inherent design flexibility and improved material properties. However, impacted composite structures have 50%-75% less strength than undamaged structures. In this work, a CFRP composite material was nondestructively characterized in order to ensure product quality and structural integrity of CFRP and one-sided pitch-catch technique was developed to measure impacted-damaged area by using an automated-data acquisition system in an immersion tank. A pitch-catch signal was found to be more sensitive than normal incidence backwall echo of longitudinal wave under defect conditions in the composite.
文摘Effects of environment conditions, such as current, wave etc., are more important for immersed tube tunnel's transportation and immersing. The hydrodynamics and stability of immersed tube tunnel during its towing and immersing are interested for departments of design and construction. A serial model tests are made in towing tank and water channel for Nanjing immersed tube tunnel, and the first immersed tunnel has been designed in Yangtzi River in China. The hydrodynamic forces and rope tensions of the tunnel are measured with strain balances when it is towed by ship and immersed by winches for a different current velocity and wave height. In addition, the stability of tunnel for a different ballast water is tested and discussed.
文摘A numerical model to predict the hydrodynamic performance of a shoreline-mounted wave energy converter, normally referred to as Oscillating Water Column (OWC), was established. Based on the 3D boundary integral equation method, the 3D Green's function was utilized to describe the hydrodynamic flow around the device. Using geometrical data of a wave absorber device symmetrically placed in a channel with various barrier depths, the hydrodynamic efficiencies were calculated for regular waves. The results were then compared with analytical results published elsewhere Malmo[8]. And the comparison is shown to be good, thus validating the proposed numerical model. Furthermore, extensive experiments were also made in a wave tank with a 1:12 scale model of an OWC device of different geometrical configurations. The experimental measurements were compared with calculations using the newly developed numerical model. The comparison, which is also shown to be satisfactory, provides further support of the correctness and the accuracy of the numerical method presented.
