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  1. dldhdz

    Autopipe v8i Plus: General shear stress and shear force output

    Dear all, if I was not mistaken, the direct shear stress will not be included by default for all piping code options except GENERAL and Stoomwezen. I was wondering whether it's possible to retrieve in-plane and out-of-plane shear forces from the analysis or not? Appreciated for any advice. Many...
  2. dldhdz

    SDVs in sequentially coupled thermal-mechanical analysis

    Hi folks, I'm doing a de-coupled thermal-mechanical analysis, i.e., thermal analysis first and then mechanical analysis. In the thermal analysis, I saved temperature and state dependent variables into output database and files. In the mechanical analysis, I want to read both temperature and...
  3. dldhdz

    Hi, how to form element stiffness matrix?

    I tried a modified C, which gives a result close to Abaqus, not exactly, comparable. This is easy to implement. I then tried a modified B, so-called B_bar method, which was tedious and result is not any close either. But I could easily misunderstood this formulation.
  4. dldhdz

    Hi, how to form element stiffness matrix?

    Thanks, Xerf. You are right, it's strange. I compared stiffness matrix, because i want to do some manipulations in global level. So far, I've got exactly cps4, cpe8 and cps8. Sorry, I did not make myself clear, all constitutive matrices use 3x3. Your formula are essentially the same with mine...
  5. dldhdz

    Hi, how to form element stiffness matrix?

    Thanks for your suggestions, xerf. 1. compared plain stress element matrix with ABAQUS cps4; 100% agreement bearing numerical errors. 2. t is the thickness, 1 as default. 3. i tried 0.25*Sum(det(J(x_i,y_i))), seemed not working 4. compare plain strain again, the same discrepancies exist. I...
  6. dldhdz

    Hi, how to form element stiffness matrix?

    thanks for your reply, xerf. i did compare with cpe4. just my results can not agree with abaqus element matrix, for the diagonal values, about 15 percent difference. I dont know why; cannot find a way to crack this.
  7. dldhdz

    Hi, how to form element stiffness matrix?

    I have been trying to reproduce element matrix for 4-node plain strain element. I used isoparametic element, Gauss_Legend integration in Matlab. Unfortunately, I found the element matrix could not match what I extracted from ABAQUS. Actually, the diagonal vaules looked bigger than corresponding...
  8. dldhdz

    Thermal Conductance Properties

    Regardless of existence of clearance, you can always define the gap conductance as a function of clearance. At least two data lines must be specified. When gap conductance is defined as a function of clearance, the value of the conductance drops to zero immediately after the last data point...
  9. dldhdz

    linking abaqus to fortran

    You need to correctly setting environment variables to allow ABAQUS to detect compilers. You can get more info from ABAQUS answers.
  10. dldhdz

    infinite elements

    Infinite elements has its own node order, which is apparently different from standard elements. Maybe you need to check whether you need to change the node order as well when you change the element type into infinite elements.
  11. dldhdz

    Warning on boundary conditions

    what's the exactly element type you are using then?
  12. dldhdz

    [ABAQUS] Energy balance v6.4-v6.7

    I've tried abaqus 661 with a small tmax, it looks ok, i mean etotal=allie-allwk
  13. dldhdz

    Von mises stress above allowable stress in material?

    ABAQUS analysis user's manual, vol1, 4.1.2.-7 Extrapolation and interpolation of element output variables The shape functions of the element are used for purposes of extrapolation and interpolation of output variables. Extrapolated values are generally not as accurate as the values calculated...
  14. dldhdz

    Von mises stress above allowable stress in material?

    could that be a result of extrapolation?
  15. dldhdz

    Acoustic infinite element eigenanalysis (abaqus)

    I'm running a job to extract natural frequencies from a fluid-structural system. It's a 2d problem, i used ac2d4 for finite acoustic element and in the boundary used acin2d2 infinite acoustic element. In message file, I found the error: NUMBER OF EIGENVALUES FOUND ON THE INTERVAL EXCEEDS THE...
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