The formula of a J integral presented by J.R.Rice is extended to problem of 2 D variable thickness plates.The extended J integral formula is derived in terms of the path independent.Then the integral conservation is v...The formula of a J integral presented by J.R.Rice is extended to problem of 2 D variable thickness plates.The extended J integral formula is derived in terms of the path independent.Then the integral conservation is verified by using finite element method.At last,the calculation results for some variable thickness plates made of photoelastic material are compared with their photoelastic test data,and the differences between them are less than 4%.It is proved that the extended J integral formula for the 2 D variable thickness plates is path independent and can be taken as a fracture pamarater for damage tolerance analysis.Furtheremore,this integral can be solved numerically by using 2 D general finite element programs.It is therefore of practical value for the fracture analysis of Ⅰ mode cracked plate with thickness which does not vary too mueh.展开更多
The definition of J-integral of interfacial crack was introduced. The three-point bending tests were can＇ied out to obtain the critical loading values when the interfacial crack initiation occurred between coatings a...The definition of J-integral of interfacial crack was introduced. The three-point bending tests were can＇ied out to obtain the critical loading values when the interfacial crack initiation occurred between coatings and substrates. The finite element analysis （FEA） was adopted to analyze the stress distribution in the specimens and compute the J-integral of the interracial crack between LX88A coating and Chinese Q345 steel. The results showed that the average value of critical J-integral is 0.70 N/m, which can be taken as the fracture parameter to evaluate the interracial fracture behavior for the three-point bending specimens of LX88A coating/Q345 steel system.展开更多
A class of problems concerning subinterface cracks interacting with the interface in metal/piezoelectric ceramic bimaterials are studied. The interaction problem is reduced to a system of integral equations with the a...A class of problems concerning subinterface cracks interacting with the interface in metal/piezoelectric ceramic bimaterials are studied. The interaction problem is reduced to a system of integral equations with the aid of the pseudo-traction-electric-displacement method. The equations are solved numerically, and the stress, intensity factor, the electric displacement intensity factor and the mechanical strain energy release rate are evaluated. Numerical results of a Cu/PZT-4 bimaterial are given and shown in figures, in which three kinds of remote loading conditions are considered to make comparisions. It is found that the electric loading at infinity plays a quite important role in the present interaction problem. In addition, a conservation law of the first component of the J k-integral, vector is found; which does lead to a consistency check to confirm the effectiveness of the PTEDM as well as the numerical results derived in this paper.展开更多
文摘The formula of a J integral presented by J.R.Rice is extended to problem of 2 D variable thickness plates.The extended J integral formula is derived in terms of the path independent.Then the integral conservation is verified by using finite element method.At last,the calculation results for some variable thickness plates made of photoelastic material are compared with their photoelastic test data,and the differences between them are less than 4%.It is proved that the extended J integral formula for the 2 D variable thickness plates is path independent and can be taken as a fracture pamarater for damage tolerance analysis.Furtheremore,this integral can be solved numerically by using 2 D general finite element programs.It is therefore of practical value for the fracture analysis of Ⅰ mode cracked plate with thickness which does not vary too mueh.
基金Supported by Tianjin Natural Science Foundation (No.08JCYBJC09100)New Teacher Research Fund for the Doctoral Program of Higher Education of China (No.20070056096) and New Century Outstanding Talented Person Plan of China.
文摘The definition of J-integral of interfacial crack was introduced. The three-point bending tests were can＇ied out to obtain the critical loading values when the interfacial crack initiation occurred between coatings and substrates. The finite element analysis （FEA） was adopted to analyze the stress distribution in the specimens and compute the J-integral of the interracial crack between LX88A coating and Chinese Q345 steel. The results showed that the average value of critical J-integral is 0.70 N/m, which can be taken as the fracture parameter to evaluate the interracial fracture behavior for the three-point bending specimens of LX88A coating/Q345 steel system.
文摘A class of problems concerning subinterface cracks interacting with the interface in metal/piezoelectric ceramic bimaterials are studied. The interaction problem is reduced to a system of integral equations with the aid of the pseudo-traction-electric-displacement method. The equations are solved numerically, and the stress, intensity factor, the electric displacement intensity factor and the mechanical strain energy release rate are evaluated. Numerical results of a Cu/PZT-4 bimaterial are given and shown in figures, in which three kinds of remote loading conditions are considered to make comparisions. It is found that the electric loading at infinity plays a quite important role in the present interaction problem. In addition, a conservation law of the first component of the J k-integral, vector is found; which does lead to a consistency check to confirm the effectiveness of the PTEDM as well as the numerical results derived in this paper.
