scholarly journals Influence of porosity on ultrasonic wave velocity, attenuation and interlaminar interface echoes in composite laminates: Finite element simulations and measurements

2016 ◽  
Vol 152 ◽  
pp. 645-653 ◽  
Author(s):  
Yosuke Ishii ◽  
Shiro Biwa ◽  
Akira Kuraishi
Keyword(s):  
Finite Element ◽  
Ultrasonic Wave ◽  
Wave Velocity ◽  
Composite Laminates ◽  
Finite Element Simulations ◽  
Ultrasonic Wave Velocity ◽  
Velocity Attenuation

The evolution of structure properties of vegetation concrete under freeze–thaw cycles

2020 ◽  
pp. 002072092093036
Author(s):  
Jiazhen Gao ◽  
Mingtao Zhou ◽  
Wennian Xu ◽  
Daxiang Liu ◽  
Jian Shen ◽  
...  
Keyword(s):  
Water Content ◽  
Ultrasonic Wave ◽  
Wave Velocity ◽  
Engineering Students ◽  
Cement Hydration ◽  
Electrical Engineering ◽  
Ultrasonic Wave Velocity ◽  
Freeze Thaw ◽  
Microstructural Parameters ◽  
Thaw Cycle

Vegetation concrete is a typical artificial composite soil commonly used for ecological restoration on slopes. The strength and stability of vegetation concrete would be reduced when it is used in areas where freeze–thaw cycles occur frequently. For exploring the changes of structural properties of vegetation concrete under freeze–thaw cycles, an indoor simulation experiment of vegetation concrete samples containing 25 and 30% water content was carried out, so as to test the changes of specimen surface, volume, ultrasonic wave velocity, shearing strength, and microscopic structure. The microstructural parameters were analyzed quantitatively with Image-Pro Plus software. The experimental results indicated that as cycles of freeze–thaw grow, the macroscopic changes of samples included steadily rising surface crack rate, increasing first and then decreasing volume, greatly reducing ultrasonic wave velocity and gradually decreasing shear strength. The inner structure of samples slowly deteriorated from overall dense to dispersed with decreasing cement hydration crystals, pores resulting from dispersion and destruction of bulky grains, higher surface porosity, and smoother particles in microscopic aspect. When compared with samples containing 25% water content, the microstructure of the 30% water content sample was more affected by the freeze–thaw cycle, and its structural weakening effect was more obvious. Reduced cement hydration crystals, lower inter-particle bonding force, and increase in the number of large pores were the main causes of degradation of vegetation concrete structure. Electrical engineering students can refer to the analysis methods in this paper to evaluate the structural performance of any electrical engineering material.

scholarly journals Texture and Cross Slip Effects on Ultrasonic Wave Velocity Changes Under Simple and Pure Shear States.

2001 ◽  
Vol 67 (660) ◽  
pp. 1402-1408 ◽  
Author(s):  
Shihua TANG ◽  
Michiaki KOBAYASHI ◽  
Setsuo MIURA ◽  
Hiroryuki FUJIKI ◽  
Kazuya IWABUCHI ◽  
...  
Keyword(s):  
Ultrasonic Wave ◽  
Wave Velocity ◽  
Pure Shear ◽  
Cross Slip ◽  
Ultrasonic Wave Velocity ◽  
Slip Effects ◽  
Velocity Changes
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