A new method, using the fracture-surface topography analysis （FRASTA）, of determining the parameters of rotation factor and CTOA is provided. The fracture surfaces are scanned by laser microscope and the height data...A new method, using the fracture-surface topography analysis （FRASTA）, of determining the parameters of rotation factor and CTOA is provided. The fracture surfaces are scanned by laser microscope and the height data is recorded to analyze. By comparing the crack extension, plastic rotation factor and COA obtained by the method of double clip gauge and by this new method respectively, the validity of it is verified. It is then used to determine the CTOA. .The critical CTOA is well determined in this paper. Also by the new method, the variation of crack opening deformation （COA and CTOA） through specimen thickness can be obtained which can＇t be obtained by the usual methods. It also can provide much information of crack extension such as direction and ratio.展开更多
Fracture-surface topography analysis （FRASTA） was successfully used to simulate the process of crack and calculate parameters of crack such as the crack opening angle （COA） and crack-tip opening angle （CTOA）. Bu...Fracture-surface topography analysis （FRASTA） was successfully used to simulate the process of crack and calculate parameters of crack such as the crack opening angle （COA） and crack-tip opening angle （CTOA）. But because the amount of calculation is large, errors are often made during the course of calculation. FRASTA simulation software, namely fracture surface analyst （FSA ） is developed and a series of center-cracked tension （CCT） and double edge notched （DEN） specimens of different materials with different sizes are tested, their fracture surfaces are scanned by non-contact 319 scanning system and the elevation data of the fracture surfaces is recorded. FSA used the recorded elevation data of fracture surfaces to simulate the process of crack based on the principle of FRASTA. Results show that FSA can accurately simulate the process and calculate the parameters of crack.展开更多
To investigate the causes that led to the formation of cracks in materials, a novel method that only considered the fracture surfaces for determining the fracture toughness parameters of J-integral for plain strain wa...To investigate the causes that led to the formation of cracks in materials, a novel method that only considered the fracture surfaces for determining the fracture toughness parameters of J-integral for plain strain was proposed The principle of the fracture-surface topography analysis （FRASTA） was used. In FRASTA, the fracture surfaces were scanned by laser microscope and the elevation data was recorded for analysis. The relationship between J-integral and fracture surface average profile for plain strain was deduced. It was also verified that the J-integral determined by the novel method and by the compliance method matches each other well.展开更多
J-integral arid crack opening displacement 8 （COD） were important parameters for characterization of fractures in engineering materials. The relationship between J-integral arid COD has been investigated for a long ...J-integral arid crack opening displacement 8 （COD） were important parameters for characterization of fractures in engineering materials. The relationship between J-integral arid COD has been investigated for a long time and was generally represented as J = m σy, δ, where σy is the yield strength arid m is a function of specimen geometry arid material properties. To determine the value of m, extensive studies and experiments have been performed. The method that used the fracture-surface topography analysis （ FRASTA ） for determining J-integral from fracture surfaces of materials was introduced. On the basis of the relationship between COD arid fracture surface average profile, the relationship between J-integral arid COD was deduced arid compared with the generally used equation. The method was experimentally confirmed to be able to provide a new way to determine the relationship between J-integral and COD.展开更多
文摘A new method, using the fracture-surface topography analysis （FRASTA）, of determining the parameters of rotation factor and CTOA is provided. The fracture surfaces are scanned by laser microscope and the height data is recorded to analyze. By comparing the crack extension, plastic rotation factor and COA obtained by the method of double clip gauge and by this new method respectively, the validity of it is verified. It is then used to determine the CTOA. .The critical CTOA is well determined in this paper. Also by the new method, the variation of crack opening deformation （COA and CTOA） through specimen thickness can be obtained which can＇t be obtained by the usual methods. It also can provide much information of crack extension such as direction and ratio.
文摘Fracture-surface topography analysis （FRASTA） was successfully used to simulate the process of crack and calculate parameters of crack such as the crack opening angle （COA） and crack-tip opening angle （CTOA）. But because the amount of calculation is large, errors are often made during the course of calculation. FRASTA simulation software, namely fracture surface analyst （FSA ） is developed and a series of center-cracked tension （CCT） and double edge notched （DEN） specimens of different materials with different sizes are tested, their fracture surfaces are scanned by non-contact 319 scanning system and the elevation data of the fracture surfaces is recorded. FSA used the recorded elevation data of fracture surfaces to simulate the process of crack based on the principle of FRASTA. Results show that FSA can accurately simulate the process and calculate the parameters of crack.
文摘To investigate the causes that led to the formation of cracks in materials, a novel method that only considered the fracture surfaces for determining the fracture toughness parameters of J-integral for plain strain was proposed The principle of the fracture-surface topography analysis （FRASTA） was used. In FRASTA, the fracture surfaces were scanned by laser microscope and the elevation data was recorded for analysis. The relationship between J-integral and fracture surface average profile for plain strain was deduced. It was also verified that the J-integral determined by the novel method and by the compliance method matches each other well.
文摘J-integral arid crack opening displacement 8 （COD） were important parameters for characterization of fractures in engineering materials. The relationship between J-integral arid COD has been investigated for a long time and was generally represented as J = m σy, δ, where σy is the yield strength arid m is a function of specimen geometry arid material properties. To determine the value of m, extensive studies and experiments have been performed. The method that used the fracture-surface topography analysis （ FRASTA ） for determining J-integral from fracture surfaces of materials was introduced. On the basis of the relationship between COD arid fracture surface average profile, the relationship between J-integral arid COD was deduced arid compared with the generally used equation. The method was experimentally confirmed to be able to provide a new way to determine the relationship between J-integral and COD.
