The plasma-MIG welding torch was developed.5A06 aluminum alloys with V-grooves were welded in a single pass in the plasma-MIG welding process and the joints were examined by X-ray diffractometry analysis and mechanica...The plasma-MIG welding torch was developed.5A06 aluminum alloys with V-grooves were welded in a single pass in the plasma-MIG welding process and the joints were examined by X-ray diffractometry analysis and mechanical tests.The orthogonal experimental design was used to study the influence of plasma-MIG welding parameters on the aluminum weld porosity.The mixed orthogonal matrix L16(4 4×2 3) and analysis of variance (ANOVA)technique were employed to optimize the welding parameters.The experimental results indicate that the effect of plasma gas flow rate is dominant,the secondary factors are MIG welding voltage,welding speed,wire feed rate and plasma current in turn.Confirmation experiments were conducted under optimum conditions and there was almost no porosity in the welded joints,thus good mechanical performance joints were obtained.展开更多
Generally, a suction control apparatus is used to examine compression properties of unsaturated clay. This is usually carried out with a pore water pressure of 0 under condition of applying pore air pressure, which is...Generally, a suction control apparatus is used to examine compression properties of unsaturated clay. This is usually carried out with a pore water pressure of 0 under condition of applying pore air pressure, which is positive pore air pressure in a triaxial compression test. It is known as the Axis Translation Technique. However in this study, the suction control apparatus does not employ a method of controlling initial degree of saturation of specimen. The method for making specimen using micro wave is used to ensure a uniform distribution of water content of specimen （microwave oven method）. Consequently, both compression properties are similar to each other. Collapse tests were carried out using specimens under the microwave oven method and air dry state. As a result, it was found that the former does not result in collapse but the latter results in a significant amount of collapse. Such occurrence of collapse is dependent on the soil structure. Therefore, the equation of effective stress for unsaturated soil proposed Bishop should not neglect as an occurrence of collapse for unsaturated soils.展开更多
文摘The plasma-MIG welding torch was developed.5A06 aluminum alloys with V-grooves were welded in a single pass in the plasma-MIG welding process and the joints were examined by X-ray diffractometry analysis and mechanical tests.The orthogonal experimental design was used to study the influence of plasma-MIG welding parameters on the aluminum weld porosity.The mixed orthogonal matrix L16(4 4×2 3) and analysis of variance (ANOVA)technique were employed to optimize the welding parameters.The experimental results indicate that the effect of plasma gas flow rate is dominant,the secondary factors are MIG welding voltage,welding speed,wire feed rate and plasma current in turn.Confirmation experiments were conducted under optimum conditions and there was almost no porosity in the welded joints,thus good mechanical performance joints were obtained.
文摘Generally, a suction control apparatus is used to examine compression properties of unsaturated clay. This is usually carried out with a pore water pressure of 0 under condition of applying pore air pressure, which is positive pore air pressure in a triaxial compression test. It is known as the Axis Translation Technique. However in this study, the suction control apparatus does not employ a method of controlling initial degree of saturation of specimen. The method for making specimen using micro wave is used to ensure a uniform distribution of water content of specimen （microwave oven method）. Consequently, both compression properties are similar to each other. Collapse tests were carried out using specimens under the microwave oven method and air dry state. As a result, it was found that the former does not result in collapse but the latter results in a significant amount of collapse. Such occurrence of collapse is dependent on the soil structure. Therefore, the equation of effective stress for unsaturated soil proposed Bishop should not neglect as an occurrence of collapse for unsaturated soils.
