The mechanical properties and fracture behaviors of 6061 aluminum alloy were investigated by the tensile shear tests and in-situ tensile shear tests with tensile shear specimen devised. The results indicate that many ...The mechanical properties and fracture behaviors of 6061 aluminum alloy were investigated by the tensile shear tests and in-situ tensile shear tests with tensile shear specimen devised. The results indicate that many slip bands parallel to tensile direction are produced on the surfaces of the specimens. With shear strain rates increasing, the shear yield stress and shear ultimate stress of 6061 aluminum alloy remain constant basically, but the shear fracture strain decreases obviously. The shear strain rates have no influence on the fracture surfaces. The grain boundaries of 6061 aluminum alloy are the weakest area and microcracks initiate at the grain boundaries parallel to tensile direction under shear stress. With the shear stress increasing, the microcracks extend and coalesce. The fracture of specimens is due to coalescence or shearing between the microcracks.展开更多
The deformation and fracture behaviors of low-carbon steel, medium-carbon steel, and high-carbon steel were studied on internal microstructure using the scanning electron microscopy in situ tensile test. The microstru...The deformation and fracture behaviors of low-carbon steel, medium-carbon steel, and high-carbon steel were studied on internal microstructure using the scanning electron microscopy in situ tensile test. The microstructure mechanism of their deformation and fracture behavior was analyzed. The results show that the deformation and fracture behavior of low-carbon steel depends on the grain size of ferrite, the deformation and fracture behavior of medium-carbon steel depends on the size of ferrite grain and pearlite lump, and the deformation and fracture behavior of high-carbon steel depends on the size of pearlite lump and the pearlitic interlamellar spacing.展开更多
Fracture represents one of the major problems associated with the selection and use of engineering materials for high temperature applications. The fracture toughness is of special relevance on the design of component...Fracture represents one of the major problems associated with the selection and use of engineering materials for high temperature applications. The fracture toughness is of special relevance on the design of components. In this work, the fracture behavior of Polypropylene/Talc composites was studied. From the results of the tensile and flexural tests conducted on the composite, scatter diagrams were made using Microsoft Excel to evaluate and show the effect of the addition of the talc filler as it affects the tensile strength, percentage elongation at break, flexural strength and modulus. In order to give additional analysis, the talc filler content effect was presented mathematically to further describe explicitly the various equations associated with each scatter diagram earlier developed using Microsoft Excel. The mathematical expression developed shows the actual talc filler content on the fracture mechanical properties of the sample composite.展开更多
This paper performed flexural test and numerical simulation of clay-beams with different water contents to study the tensile fracture of clay soil and the relevant mechanisms.The crack initiation and propagation proce...This paper performed flexural test and numerical simulation of clay-beams with different water contents to study the tensile fracture of clay soil and the relevant mechanisms.The crack initiation and propagation process and the accompanied strain localization behaviors were all clearly observed and analyzed.The exponential cohesive zone model was proposed to simulate the crack interface behavior of the cohesive-frictional materials.The experimental results show that the bending capacity of clay-beams decrease with the water content,while those of the crack mouth opening displacement,crack-tip strain and the strain localization range increase.The numerical predictions successfully reproduce the evolving tensile cracks and the strain localization phenomenon of the clay beams with different fracture ductility,which demonstrates the validity of the proposed cohesive zone model in modelling clay fractures.展开更多
This paper deals with the fracture feature of three kinds of polyester fibers with differentstructures under different tensile conditions.We studied fracture initiation,crack propagationand ultimate fracture character...This paper deals with the fracture feature of three kinds of polyester fibers with differentstructures under different tensile conditions.We studied fracture initiation,crack propagationand ultimate fracture characteristics under tension of polyester fibers.The fracture features ofpolyester fibers are related with fiber structure and tensile condition.Crack is initiated in fibersurface.It propagates from outside to inside and eventually causes rupture of the fiber.In addi-tion,it is stated also that the analysis on tensile fracture feature of fibers might be confirmed bydynamic testing technique of scanning electron microscopy.展开更多
The effects of cyclic loading on crack growth, fracture feature and rupture life of superalloy GH2132 have been studied in the present paper. The crack growth tests were carried out at 550 on compact tension specimens...The effects of cyclic loading on crack growth, fracture feature and rupture life of superalloy GH2132 have been studied in the present paper. The crack growth tests were carried out at 550 on compact tension specimens under a wide range of load levels and various periods of hold time, and the fracture surfaces were examined on a scanning electron microscope. The results show that, for both static and cyclic creep, Stage-I of crack growth is related with initial test stress, during which the crack extension is about 0.5mm, and that the final effect of cyclic loading on rupture life depends on the counteraction of its two reversed effects on crack growth rate before and after the point n=0.2.展开更多
基金supported by the Education Department of Hebei Province, China (Nos. 933005 and ZD2010209)
文摘The mechanical properties and fracture behaviors of 6061 aluminum alloy were investigated by the tensile shear tests and in-situ tensile shear tests with tensile shear specimen devised. The results indicate that many slip bands parallel to tensile direction are produced on the surfaces of the specimens. With shear strain rates increasing, the shear yield stress and shear ultimate stress of 6061 aluminum alloy remain constant basically, but the shear fracture strain decreases obviously. The shear strain rates have no influence on the fracture surfaces. The grain boundaries of 6061 aluminum alloy are the weakest area and microcracks initiate at the grain boundaries parallel to tensile direction under shear stress. With the shear stress increasing, the microcracks extend and coalesce. The fracture of specimens is due to coalescence or shearing between the microcracks.
文摘The deformation and fracture behaviors of low-carbon steel, medium-carbon steel, and high-carbon steel were studied on internal microstructure using the scanning electron microscopy in situ tensile test. The microstructure mechanism of their deformation and fracture behavior was analyzed. The results show that the deformation and fracture behavior of low-carbon steel depends on the grain size of ferrite, the deformation and fracture behavior of medium-carbon steel depends on the size of ferrite grain and pearlite lump, and the deformation and fracture behavior of high-carbon steel depends on the size of pearlite lump and the pearlitic interlamellar spacing.
文摘Fracture represents one of the major problems associated with the selection and use of engineering materials for high temperature applications. The fracture toughness is of special relevance on the design of components. In this work, the fracture behavior of Polypropylene/Talc composites was studied. From the results of the tensile and flexural tests conducted on the composite, scatter diagrams were made using Microsoft Excel to evaluate and show the effect of the addition of the talc filler as it affects the tensile strength, percentage elongation at break, flexural strength and modulus. In order to give additional analysis, the talc filler content effect was presented mathematically to further describe explicitly the various equations associated with each scatter diagram earlier developed using Microsoft Excel. The mathematical expression developed shows the actual talc filler content on the fracture mechanical properties of the sample composite.
基金sponsored by the National Key Research and Development Program of China(No.2016YFC0800200)the National Basic Research Program of China(No.2014CB047000),and the NSFC(Grant No.51578502).
文摘This paper performed flexural test and numerical simulation of clay-beams with different water contents to study the tensile fracture of clay soil and the relevant mechanisms.The crack initiation and propagation process and the accompanied strain localization behaviors were all clearly observed and analyzed.The exponential cohesive zone model was proposed to simulate the crack interface behavior of the cohesive-frictional materials.The experimental results show that the bending capacity of clay-beams decrease with the water content,while those of the crack mouth opening displacement,crack-tip strain and the strain localization range increase.The numerical predictions successfully reproduce the evolving tensile cracks and the strain localization phenomenon of the clay beams with different fracture ductility,which demonstrates the validity of the proposed cohesive zone model in modelling clay fractures.
文摘This paper deals with the fracture feature of three kinds of polyester fibers with differentstructures under different tensile conditions.We studied fracture initiation,crack propagationand ultimate fracture characteristics under tension of polyester fibers.The fracture features ofpolyester fibers are related with fiber structure and tensile condition.Crack is initiated in fibersurface.It propagates from outside to inside and eventually causes rupture of the fiber.In addi-tion,it is stated also that the analysis on tensile fracture feature of fibers might be confirmed bydynamic testing technique of scanning electron microscopy.
文摘The effects of cyclic loading on crack growth, fracture feature and rupture life of superalloy GH2132 have been studied in the present paper. The crack growth tests were carried out at 550 on compact tension specimens under a wide range of load levels and various periods of hold time, and the fracture surfaces were examined on a scanning electron microscope. The results show that, for both static and cyclic creep, Stage-I of crack growth is related with initial test stress, during which the crack extension is about 0.5mm, and that the final effect of cyclic loading on rupture life depends on the counteraction of its two reversed effects on crack growth rate before and after the point n=0.2.
