Showing 5 results for Shear Strength
S. M. Haeri, N. Sadati and R. Mahin-Rousta,
Volume 20, Issue 2 (4-2001)
Abstract
In this research, behaviour of clayey soils under triaxial loading is studied using Neural Network. The models have been prepared to predict the stress-strain behaviour of remolded clays under undrained condition. The advantage of the model developed is that simple parameters such as physical characteristics of soils like water content, fine content, Atterberg limits and so on, are used to model the stress-strain behaviour of clays under triaxial loading, without performing exact and time-consuming tests on samples.
Results from the network show that neural network is a good tool for prediction of stress-strain behaviour of clayey soils using simple physical characteristics of such soils
M.a.rowshanzamir and A. Jafari,
Volume 24, Issue 2 (1-2006)
Abstract
Cohesive-frictional soils are widely used in the construction of embankment structures and due to the method of construction, i.e. applying compactive efforts in the vertical direction in these cases, the occurrence of anisotropy in the soil strength and permeability seems to be inevitable. In this study, attempts have been made to evaluate the shear strength of c-f soils through modifying a large shear box apparatus. Conducting more than 108 direct shear tests, the effects of compaction method and moisture on the shear strength anisotropy of a selected c-f soil (a clayey sand) have then been
investigated. According to the test results, firstly strength anisotropy was observed in all the soil specimens and the shear strength in the vertical direction was about 14% to 21% higher than that in the horizontal direction. Secondly, it was found that an increase in the compaction moisture led to an increase in the degree of anisotropy. Furthermore, the anisotropy in the cohesive strength was more pronounced in the specimens with a moisture content higher than the optimum one. The highest degree of anisotropy was observed in the specimens compacted by impacting effort and the lowest one belonged to those with the vibratory compaction.
M.r. Khanzadeh Gharah Shiran, H. Bakhtiari, M. Mohammad Javadi,
Volume 36, Issue 3 (11-2017)
Abstract
In this research, the effect of standoff distance and explosive material thickness on metallurgical features of explosive welding connection of copper to 304 stainless steel has been investigated. Experimental analysis were performed using optical microscopy, scanning electron microscopy, microhardness test and tensile shear strength test. The results indicated that due to severe plastic deformation in welding, both grain elongation and refinement occurred near the connection. Also, increasing of welding parameters led to an increase in the locally melted zones. The results showed that chemical composition of the melted zone consisted of elements of both flyer and base plates. By decreasing the explosive material thickness and standoff distance, the hardness of copper interface zone decreased from 103.4 HV to 99.8 HV. Moreover, increasing the temperature in stainless steel connection led to decreased hardness. As such, the maximum tensile shear strength of 244 MPa was observed in the sample with 79 mm explosive thickness and 3 mm standoff and the minimum tensile shear strength of about 208 MPa in the sample with 46 mm explosive thickness and 3 mm standoff. By decreasing explosive thickness and standoff, the bond strength decreased, too.
M. Soltani Samani, A. Bahrami, F. Karimzadeh,
Volume 38, Issue 4 (1-2020)
Abstract
In this study, joining of Ni3Al intermetallic compounds using the transient liquid phase (TLP) process with Cu interlayer was investigated. The binding process was carried out in a vacuum furnace at a temperature of 1050 °C for different times of 30, 60, 90 and 120 minutes. The effect of time variation on microstructure and mechanical properties of the joint zone was investigated. The EDS analysis results of the joints proved formation of the athermally solidified zone (ASZ), isothermally solidified zone (ISZ) and diffusion affected zone (DAZ) at different times. After 90 minutes, brittle eutectic phases still exist in the joint line. However, by increasing the process time to 120 minutes, a copper-rich solid solution was formed in the joint line. Maximum hardness was attained in DAZ region and due to formation of more brittle compounds. By increasing the process time to 90 min, the hardness in the joint center-line increased. After 120 min, the hardness in the joint center-line decreased to about 224 HV. Maximum shear strength was achieved to be about 60 MPa at a process time of 30 minutes and due to formation of Ni-rich matrix at the joint. With increasing time to 90 min, the shear strength decreased to about 34 MPa. After 120 minutes and due to formation of copper-rich solid solution as well as disappearance of eutectic compounds, shear strength again increased to about 44 MPa. Investigation of fracture surfaces showed that until 90 minutes, fracture mode was mainly brittle whereas by increasing time to 120 minutes, a more ductile fracture occurred.
M. Jafari, M. Rafiei, H. Mostaan,
Volume 39, Issue 2 (8-2020)
Abstract
In this research, the effect of temperature and time on the properties of AISI420/SAF2507 dissimilar joint produced by transient liquid phase bonding process was investigated. A BNi-2 interlayer with 25 μm thickness was inserted between two dissimilar steel samples. The bonding process was performed at 1050 oC and 1100 oC for different bonding times. The microstructures of the joints were studied using optical microscope, scanning electron microscope and energy dispersive X-ray spectroscopy. Microhardness and tensile shear strength of bonded samples were investigated. Isothermal solidification was completed for the joints bonded at 1050 oC and 1100 oC for 45 min and 30 min, respectively. ASZ and ISZ areas of the bonding zone at the bonding temperature of 1050 oC indicated the highest (520 HV) and the lowest (300 HV) microhardness values, respectively. Sample bonded at 1050 oC for 1 min indicated the lowest tensile strength (196 MPa) and sample bonded at 1100 oC for 60 min indicated the highest tensile strength (517 MPa).
