Additive manufacturing (AM) cannot meet the manufacturing requirements of speci c large structures, so use the welding method to joint the small size parts of AM to solve the problem. In work, the laser weld 3mm thick samples cut from WAAM block under different laser powers and welding directions to explore the feasibility of technology. The properties evolution, and weldability of the laser-welded wire arc additive manufactured Al-Cu alloy joints are investigated. The results indicate that the wire arc additive manufactured Al-Cu alloy has excellent laser weldability without apparent detection. The microstructures of the laser-welded joints consist of columnar grains, dendrites and ne equiaxed grains. The 3500 W laser power joint has higher tensile strength and elongation than other laser powers, reaching 203.48 MPa, 4.13%. Compared with the different welding direction joints, "0°and 0°" has the higher tensile strength and elongation, reaching 180.77 MPa, 2.40%. The microstructures have a weak effect, but the anisotropy plays a signi cant role in the tensile properties. This study has demonstrated that it is possible to laser-welded WAAM samples, and provide solutions that AM technology di cultly produces large size parts.
Abstract. Lining crack is a primary disease in water conveyance tunnel engineering, and accurate analysis of the stability of lining structure with cracks is critical. Based on the theory of fracture mechanics, the contact model has been used to simulate the contact friction effect of crack surfaces. Combined with the fracture criterion of concrete, the safety evaluation methods for tunnel lining structure with cracks has been established. Taking a water conveyance tunnel for water diversion project as an example, the paper analyzes the influences of crack position and crack angles on the safety of lining structure based on calculating models, and the influences the stability of the tunnel lining with cracks.
Additive manufacturing (AM) cannot meet the manufacturing requirements of specific large structures, so use the welding method to joint the small size parts of AM to solve the problem. In work, the laser weld 3mm thick samples cut from WAAM block under different laser powers and welding directions to explore the feasibility of technology. The properties evolution, and weldability of the laser-welded wire arc additive manufactured Al-Cu alloy joints are investigated. The results indicate that the wire arc additive manufactured Al-Cu alloy has excellent laser weldability without apparent detection. The microstructures of the laser-welded joints consist of columnar grains, dendrites and fine equiaxed grains. The 3500 W laser power joint has higher tensile strength and elongation than other laser powers, reaching 203.48 MPa, 4.13%. Compared with the different welding direction joints, “0°and 0°” has the higher tensile strength and elongation, reaching 180.77 MPa, 2.40%. The microstructures have a weak effect, but the anisotropy plays a significant role in the tensile properties. This study has demonstrated that it is possible to laser-welded WAAM samples, and provide solutions that AM technology difficultly produces large size parts.
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