Blog posts

Mechanics of Materials Toolbox for Maple screencasts

http://youtu.be/czz_uw0918E 

Dear Everyone,

Now, I am writing Abaqus’s subroutine (Vumat) for modelling fracture and damage in Ferritic Steels.

The failure theory I have to use in my PhD research is the Rousselier’s Theory. 

 I try to write Vumat by following the procedure of Rousselier model integration in PhD thesis namely ‘3D CAFE modelling of transitional ductile - brittle fracture in steels’ that can see from http://seis.bris.ac.uk/~mexas/thesis.pdf (Appendix.B). 

Dear All,

I am modeling 3D beams with arbitrary cross sections and for that purpose I need to calculate the warping function numerically. The warping function ψ(y,z) is defined as a solution of the following Laplace equation with Neumann boundary conditions:

∂2ψ/∂y2 + ∂2ψ/∂z2 = 0 in Ω,

∂ψ/∂n = z*ny - y*nz on Γ,

where Ω is the cross sectional area, and Γ is its contour. This system can be solved by different numerical methods, for example, finite element method, boundary element method, finite differences...

Numerically I obtain that

Good mourning, it is well known that the cohesive forces models permet an easy and less combersome computation of the crack problems, these models formulated in term of stress are accompained with a scale effects because of the presence of a crachteristic lengths like the critical opening/sliding value, and the length of the cohesive zone at the begining of the propagation. In order to set the values of the characteristic lengths of the model used in the simulation for a given material, it is intressting to do that through an experimental tests like a compact tests.

hello,

     I have encountered a problem to calculate the stress at interfacial Guass point of each hexahedron element. Since the effective stress is needed to decide whether a cohesive element should be inserted when using the extrinsic cohesive element model, the stress at interfacial Guass point of each element is chosen to calculate effective stress. In the calculation process, the stress at Guass point of each hexaderon element can be obtained.Is there anyone who knows how to calculate the interfacial stress accurately? I would appreciate your comments.

Dr. Martin at Colorado School of Mines alerted us the unfortunate news of the passing away of Prof. Maurice Jaswon, a pioneer of boundary integral equation/boundary element method. An obituary is published by the London Daily Telegraph:
http://www.telegraph.co.uk/news/obituaries/technology-obituaries/897734…

i want to carry out a nonlinear static pushover analysis for a concrete dam, i'm using the concrete damage plasticity model for the above. i'm able to carry out the frequency analysis for the model, but after applying any kind of load the the job gets aborted in both static analysi and static riks analysis.

in static analysis it does not converge, whereas in  static riks analysis it says a zero displacement step ha been encountered and analysi cannot proceed..

can anyone please help me out tof this..

thanks in advance

shijo antony (IIT-R) 

Openings for two graduate studentship (Master/Ph.D) are available for the fall semester, 2012 in the Department of Mechanical and Manufacturing Engineering at the Univeristy of Manitoba. Students who have a strong background in materials simulations (molecular dynamics, monte carlo simulations, or phase field) are especially encouraged to apply. The potential students will work on one or more of the following projects: (1) Solute effects on grain boundary diffusivity/mobility; (2) Microplasticity in metallic glass and nanocomposites; (3) Plasticity in metal nanowires.

Post-doctoral position is available in the area of ultrasonic nondestructive evaluation (strong background and experience in ultrasonic experiment and modeling are required). The focus area is ultrasonic study of like polycrystalline materials, composites and adhesive bonds. State of the art ultrasonic laboratories and other characterization facilities are available. More details will be provided to interested individuals.
Interested candidates should contact

Three PhD studentships available at Cardiff University. Deadline Friday 24th of February.

Assuming you get a CSC scholarship, this fellowship will waive your tuition fee for study in computational mechanics in our group. 

Please APPLY ONLINE to the University and send me (stephane dot bordas at gmail dot com) a one paragraph research proposal about what you intent to work on. Themes are:

- multiscale fracture

- meshless methods

- extended finite element methods

- moving boundary problems

- fibrous flows