scholarly journals Characterization of dynamic tensile and shear strength of safety bolts in light collision safety devices of a train

Author(s):  
J. S. Kim ◽  
H. Huh ◽  
T. S. Kwon
2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Karl Niklas Hansson ◽  
Stig Hansson

The surface roughness affects the bone response to dental implants. A primary aim of the roughness is to increase the bone-implant interface shear strength. Surface roughness is generally characterized by means of surface roughness parameters. It was demonstrated that the normally used parameters cannot discriminate between surfaces expected to give a high interface shear strength from surfaces expected to give a low interface shear strength. It was further demonstrated that the skewness parameter can do this discrimination. A problem with this parameter is that it is sensitive to isolated peaks and valleys. Another roughness parameter which on theoretical grounds can be supposed to give valuable information on the quality of a rough surface is kurtosis. This parameter is also sensitive to isolated peaks and valleys. An implant surface was assumed to have a fairly well-defined and homogenous “semiperiodic” surface roughness upon which isolated peaks were superimposed. In a computerized simulation, it was demonstrated that by using small sampling lengths during measurement, it should be possible to get accurate values of the skewness and kurtosis parameters.


Engineering characterization which are useful for "temperate" zone soils usually fail to predict the field performance of bauxitic soils, because the index tests upon which the characterization are based are not always reproducible for bauxitic soils. Fifteen (15) bauxitic soil of undisturbed and disturbed samples from 3 distinct sites in Kuantan, all derived from basalt parent rock but representing various stages of weathering were subjected to engineering and mineralogic tests. Values for cohesion and friction angles are evaluated. Soils from Semambu has the highest moisture content of 33.27%, the cohesion value is however lower compared to Bukit Goh which has moisture content of 21.74%. Study are further done to discover the relationship with cohesion and friction angles. Thus, by measuring the cohesion and friction angle can evaluate the performance of bauxite shear strength.


2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Mi Tian ◽  
Xiaotao Sheng

Applying random field theory involves two important issues: the statistical homogeneity (or stationarity) and determination of random field parameters and correlation function. However, the profiles of soil properties are typically assumed to be statistically homogeneous or stationary without rigorous statistical verification. It is also a challenging task to simultaneously determine random field parameters and the correlation function due to a limited amount of direct test data and various uncertainties (e.g., transformation uncertainties) arising during site investigation. This paper presents Bayesian approaches for probabilistic characterization of undrained shear strength using cone penetration test (CPT) data and prior information. Homogeneous soil units are first identified using CPT data and subsequently assessed for weak stationarity by the modified Bartlett test to reject the null hypothesis of stationarity. Then, Bayesian approaches are developed to determine the random field parameters and simultaneously select the most probable correlation function among a pool of candidate correlation functions within the identified statistically homogeneous layers. The proposed approaches are illustrated using CPT data at a clay site in Shanghai, China. It is shown that Bayesian approaches provide a rational tool for proper determination of random field model for probabilistic characterization of undrained shear strength with consideration of transformation uncertainty.


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