# J integral

Dear All members;

I am derived J_integral for dynamic crack propagation, and i have some things that i not yet understood:

1. Why is the integral path must start on one crack sureface and proceeds counter-clockwise to the oposite crack sureface.

2. Why is the value of J_integral independent the radius of integral path at each time increment.

3. What is the difference if we chose the far path and near (close to) path from the crack tip.

Would you please explain for me, thank you very much,

Best Regards,

Chau

### FAD Level 2B and J-Integral

Hi

I have just start working on FAD Level 2B for pipes,I want to know how i can use J-Integral for this method

Regards,

Ali

### I just use Dynamic

I just use Dynamic J-integral for crack propagation in 2D. So I i dont know for pipes in your research. You can find a simple method to get SIFs because J-integral is a complex method, I think. Good luck

### Hi Linh,   I suggest

Hi Linh,

I suggest you to read the book by Freund : Dynamic Fracture Mechanics, Cambridge University Press, 1998. You will find all you need to know.

Manh Ha

### J-integral and residuel stress(initial condition)

I work about :Modelling and digital simulation of the structures (material:aluminuim) fissured under residual stresses, I have the problem to calculate the J-integral when I have  in initial condition residuel stress, because Abaqus define that

Initial stresses are not considered in the definition of contour integrals. Therefore, contour integral calculations for analyses including initial stresses in the regions used for the contour integral calculations will not be correct

I have may others problems see: Modelling and digital simulation of the structures fissured under residual stresses

Can you help me

### CRACK PROPAGATION

HI

i have the same problem like Mr Nihat, i have to track cracks in solids.

i want to help me in this task.

if one can provide some code, that'll be very kind