Fracture profile roughnesses and fractal dimensions of fracture traces were measured on a fatigued Ti-6Al-4V alloy.It is found that although fractal dimension can well reflect the variation of fracture traces with the...Fracture profile roughnesses and fractal dimensions of fracture traces were measured on a fatigued Ti-6Al-4V alloy.It is found that although fractal dimension can well reflect the variation of fracture traces with the measuring units,it is difficult to apply it to quantitative analysis of fractured surfaces because of the dependence of the meas- ured profile roughness on the measuring units.Based on fractal concept.an alternative equation lgR_l(η)=lgR_o-(D-1)lgη was obtained.in which we intro- duced a parameter of intrinsic profile roughness to evalu- ate fracture profile roughness without restriction of the measuring units employed.展开更多
Generalized Lamb surface waves are generated in a surface region when ultrasonic waves are incident to the layered substrates such as painted specimen in liquid. Then, backward radiated waves are returned to the direc...Generalized Lamb surface waves are generated in a surface region when ultrasonic waves are incident to the layered substrates such as painted specimen in liquid. Then, backward radiated waves are returned to the direction of incidence by scattering and energy radiation of the surface waves. Hence, the backward radiation could be used in assessing the interracial state between layer and substrate because the surface wave is sensitive to the change of physical properties in a surface region. Painting surface treatment of commercial products and articles occasionally hide the surface region trouble such as roughness and crack. The evaluation of interfacial state under painting layer is very important in the prevention of great accidence, hence the evaluation technique should be nondestructive, fast and easy applicable to the fields. The backward radiations were measured for the painted glass with periodic interfacial roughness immersed in water tank. The effect of interfacial roughness on the angular pattern and frequency spectrum of the ultrasonic backward radiation was investigated to develop the nondestructive technique for interfacial roughness evaluation.展开更多
To reduce friction and improve clarity of steel surfaces, laser texturing was used to produce known surface roughness profile on rolled surfaces using a Nd:YAG laser. Laser texturing process was analyzed to select the...To reduce friction and improve clarity of steel surfaces, laser texturing was used to produce known surface roughness profile on rolled surfaces using a Nd:YAG laser. Laser texturing process was analyzed to select the laser parameters. The surface roughness hardness and abrasion resistance were then measured and analyzed. The results show that the surface roughness is harder than the matrix, which fits for the requirements of laser texturing. The surface roughness also has good abrasion resistance. The intensity and distribution of the single pulse are the key points affecting the surface roughness profile.展开更多
文摘Fracture profile roughnesses and fractal dimensions of fracture traces were measured on a fatigued Ti-6Al-4V alloy.It is found that although fractal dimension can well reflect the variation of fracture traces with the measuring units,it is difficult to apply it to quantitative analysis of fractured surfaces because of the dependence of the meas- ured profile roughness on the measuring units.Based on fractal concept.an alternative equation lgR_l(η)=lgR_o-(D-1)lgη was obtained.in which we intro- duced a parameter of intrinsic profile roughness to evalu- ate fracture profile roughness without restriction of the measuring units employed.
基金supported by the National Research Foundation of Koreaby the National Natural Science Foundation of China(NSFC)
文摘Generalized Lamb surface waves are generated in a surface region when ultrasonic waves are incident to the layered substrates such as painted specimen in liquid. Then, backward radiated waves are returned to the direction of incidence by scattering and energy radiation of the surface waves. Hence, the backward radiation could be used in assessing the interracial state between layer and substrate because the surface wave is sensitive to the change of physical properties in a surface region. Painting surface treatment of commercial products and articles occasionally hide the surface region trouble such as roughness and crack. The evaluation of interfacial state under painting layer is very important in the prevention of great accidence, hence the evaluation technique should be nondestructive, fast and easy applicable to the fields. The backward radiations were measured for the painted glass with periodic interfacial roughness immersed in water tank. The effect of interfacial roughness on the angular pattern and frequency spectrum of the ultrasonic backward radiation was investigated to develop the nondestructive technique for interfacial roughness evaluation.
基金Supported by the Excellent Young Teachers Program of Ministry of Education
文摘To reduce friction and improve clarity of steel surfaces, laser texturing was used to produce known surface roughness profile on rolled surfaces using a Nd:YAG laser. Laser texturing process was analyzed to select the laser parameters. The surface roughness hardness and abrasion resistance were then measured and analyzed. The results show that the surface roughness is harder than the matrix, which fits for the requirements of laser texturing. The surface roughness also has good abrasion resistance. The intensity and distribution of the single pulse are the key points affecting the surface roughness profile.
