The effects of loading-direction and strain-rate on the mechanical behaviors of human frontal skull bone

Author(s):  
Xuedong Zhai ◽  
Eric A. Nauman ◽  
Dana Moryl ◽  
Roy Lycke ◽  
Weinong W. Chen
2019 ◽  
Vol 956 ◽  
pp. 244-252
Author(s):  
Xiao Ju Gao ◽  
Chao Li ◽  
Hasigaowa ◽  
Zhi Peng Li ◽  
Yu Guang Bao ◽  
...  

The quasi-static and dynamic compressive mechanical behaviors of two kinds of fiber reinforced SiC-matrix composites including 2D-C/SiC and 2D-SiC/SiC were investigated. Their compressive behaviors of materials at room temperature and strain rate from 10-4 to 104 /s were studied. The fracture surfaces and damage morphology were observed by scanning electron microscopy (SEM). The results showed that the dynamic failure strengths of the two kinds of fiber reinforced SiC-matrix composites obey the Weibull distribution. The Weibull modulus of the two materials were 13.70 (2D-C/SiC) and 5.66 (2D-SiC/SiC), respectively. It was found that the two kinds of fiber reinforced ceramic matrix composites presented a transition from brittle to tough with the decrease of strain rate. The 2D-SiC/SiC materials demonstrated a more HYPERLINK "http://dict.cnki.net/dict_result.aspx?searchword=%e6%98%be%e8%91%97%e7%9a%84&tjType=sentence&style=&t=remarkable"significant strain rate sensitivity and smoother fracture surface compared to the 2D-C/SiC composites, implying that the former composites present brittle features. This was because the SiC/SiC composites possessed high bonding strength in interface of fiber/fiber and fiber/matrix is very strong.


2006 ◽  
Vol 519-521 ◽  
pp. 847-852
Author(s):  
Suk Bong Kang ◽  
Jae Woon Kim ◽  
Hyoung Wook Kim

Recently the method for obtaining ultra-fine grained metallic materials has developed using severe plastic deformation (SPD), such as equal channel angular pressing (ECAP), accumulative roll bonding (ARB), torsion straining, and warm multiple deformation (WMD) etc. In order to enhance thermal stability of ultra-fine grained aluminum alloys manufactured by SPD process, the addition of Sc and Zr elements has been considered to devise fine Al3Sc, Al3Zr and Al3(Scx Zr1-x) precipitates for inhibiting the grain growth. In this study, the microstructure evolution has been investigated in Al-Mg alloys with and without Sc and Zr addition during the warm multiple deformation process. In addition Al-Mg alloys were compressed at a strain rate of 10-1 sec-1 by two different routes, that is, route A and route B. Route A is to rotate the specimen throughout 90o around the vertical axis of loading direction at every pass. Route B is to rotate the specimen throughout 90o around the parallel axis of loading direction and then rotate it again as route A. The specimen deformed by route B had finer grain size and more uniform distribution of grains than those deformed by route A. When the warm multiple deformation process repeated up to 8 passes at 673 K, the specimen consisted of ultra-fine grained structure with the average grain size less than 3 μm. The superplastic behavior can also be observed at the high strain rate and low temperature regime.


2011 ◽  
Vol 243-249 ◽  
pp. 4634-4637 ◽  
Author(s):  
Li Min Zhang ◽  
Zhi Jun Li ◽  
Qing Jia ◽  
Guang Wei Li ◽  
Wen Feng Huang

The uniaxial compression test was performed on artificial freshwater ice with a precise control-temperature unit compression tester of ice under -5, -10, -15, -20 and-30°C temperatures and strain rates ranging from 10-8 to 10-2 s-1. The loading direction was parallel to ice surface. The results showed that the compressive strength was very sensitive to the strain-rate. The uniaxial compressive strengths reached the maximum value at the ductile-brittle transition region, and the region was gradually close to the lower strain-rate with the decreasing temperature of test. Both the strain-rate and uniaxial compressive strength dependences could be expressed in terms of power function in the relevant ductile range of strain-rate. The tests also revealed that failure stress of ice increases with decreasing of temperature at the same strain rate.


2019 ◽  
Vol 222 ◽  
pp. 110923 ◽  
Author(s):  
Yinggang Miao ◽  
Hengning Zhang ◽  
He He ◽  
Qiong Deng

2018 ◽  
Vol 183 ◽  
pp. 03014 ◽  
Author(s):  
Christine Baumgart ◽  
Christian Weigelt ◽  
Christos G. Aneziris ◽  
Lutz Krüger

As the mechanical properties of honeycomb structures are influenced by several parameters, detailed analysis is necessary before their potential application in transportation industry components. Previous Finite Element Model (FEM)-based numerical analysis demonstrated that variation in cell geometry affects the achievable strength level and, thus, the energy absorption capability. According to this FEM study, the Kagome geometry – an ordered sequence of hexagons and triangles – exhibits properties that are particularly promising when compared to the square-celled structures investigated to date. When the load is applied parallel to the channel axis (the out-of-plane direction), the increment of strength is comparatively low, whereas in the in-plane direction (loading orthogonal to the channel axis), the dissipated specific energy can reach almost double that of the square-celled structure. In this study, the results of static and dynamic compression tests – performed in the out-of-plane and in-plane modes – are presented to examine the influence of strain rate and loading direction on the characteristic deformation stages of squarecelled and Kagome structures. Particular attention is paid to deformation induced martensite formation in the cell wall material, indicating the TRansformation Induced Plasticity (TRIP) effect as a function of applied cell geometry, strain rate and loading direction.


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