Category Archives: Engineering

Field variables in code-aster

Available variables in code aster that I tested. I will be updating this table after testing other elements.

FIELD NAME AVAILABLE VARIABLES APPLICABLE MODEL TYPES NON- APPLICABLE MODEL
EFGE_ELNO N,VY,VZ,MT, MFY,MFZ POU_D_E, 3D, 2D
SIEF_ELNO POU_D_T, POU_D_E
POU_D_TG, POU_D_T_GD
FORC_F FX FY FZ MX MY MZ
DEPL_R DX DY DZ DRX DRY MARTINI DRZ
SIEF_R SIXX SIYY SIZZ SIXY SIXZ SIYZ 3D
SIEF_R NR VY VZ MT MFY MFZ Discrete elements
SIEF_R NXX NYY NXY MXX MYY MXY QX QY HULL
SIEF_R BR Beam with wrapping
SIEF_R POU_D_T, POU_D_E
POU_D_TG, POU_D_T_GD
SIEF_ELGA 3D,2D, DKT, DST, Q4G, Q4GG, COQUE_3D, BARR, 2D_BARR POU_D_T, POU_D_E
POU_D_TG, POU_D_T_GD
SIGM_ELGA 3D,2D, DKT, DST, Q4G, Q4GG, COQUE_3D POU_D_T, POU_D_E
POU_D_TG, POU_D_T_GD
SIGM_ELNO POU_D_T, POU_D_E
POU_D_TG, POU_D_T_GD
EFGE_ELNO

Effort

3D, 2D
EFGE_ELNO 3D, 2D
FORC_NODA

nodal forces

DX DY DZ DRX DRY MARTINI DRZ
EPSI_ELGA
EPSG_ELGA 3D Hulls, plates
(except DKTG
and Q4GG), PIPES, Multifibre beams
EPME_ELGA 3D Hulls, plates
(except DKTG
and Q4GG)
EPMG_ELGA 3D Hulls, plates
(except DKTG
and Q4GG), PIPES, Multifibre beams
EPSP_ELGA 3D Hulls, plates
(except DKTG
and Q4GG)
EPSI_ELNO

 

3D
EPSG_ELNO 3D Hulls, plates
(except DKTG
and Q4GG), PIPES, Multifibre beams
EPME_ELNO 3D Hulls, plates
(except DKTG
and Q4GG)
EPMG_ELNO 3D Hulls, plates
(except DKTG
and Q4GG), PIPES, Multifibre beams
EPSP_ELNO 3D Hulls, plates
(except DKTG
and Q4GG)
DEGE_ELGA

 

Plates,
Coques1D
3D
DEGE_ELNO

 

Plates,
Coques1D
3D
VARI_ELGA BARR, 2D_BARR

Some clues:

DEGE : deformations generalized on the elements of beam or hull
ELNO: Node- calculation carried out by extrapolation with the nodes of the quantities at the points of Gauss
ELGA:Gauss point
NOEU:

EF~:Effort

SI~: Stress

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Beginning with Code Aster and Salome Meca

Code aster is an opensource (free) FEM analysis software targetted to structural, thermal and aucostic analysis. It is available for windows and linux. This software can be used for non-linear analysis and thus is quite useful for engineering studies epscially for academic research. But the sofware is little difficult to use for begineers. I am sharing some introductory videos to get started with this software. You can visit the forum for discussion on your specific problem.

  • Analysis of a simple beam

  • Non-linear analysis of simple steel rod

  • Modeling hardeing of steel

  • Analysis of plate and plotting stress strain diagram

Installing Fortran Compiler for Visual Studio 2017

Fortran has come a long way than we had studied in high-school in 19xx. Its now fully supported within Microsoft visual studio. To install Fortran with VS IDE support, ensure the followings:

Modify/Install the installation file of VS 2017 Community edition (its free!) and install support for Desktop development with C++ .  This step will ensure that the Fortran compiler is available from within the VS2017. (Ref: https://software.intel.com/en-us/articles/installing-microsoft-visual-studio-2017-for-use-with-intel-compilers).

  1. During installation/modification under the Workloads view (shown below), select the checkbox to install the Desktop development with C++ component.
  2. To build applications to run on Windows XP*, check the Windows XP support for C++ component in Summary window
  3. Continue with the installation

Download Fortran compiler- Intel® Parallel Studio XE (its free too!) from https://software.intel.com/en-us/qualify-for-free-software/student. You need to register with academic email address. Install it after downloading.

For offline installation you can download licence file from your profile page after logging in. (Ref: https://software.intel.com/en-us/articles/resend-license-file)

 

  • Click on any active serial number to go to the corresponding Manage License page.
  • There are two icons on the License File header ‘Download license file’ and ‘Resend license file to my email’.

 

interFortranVisualStudio

 

 

Catchment area calculation in QGIS

The method is similar to any other GIS method. The steps are as follows; the main step is highlighted in bold fonts. It is up to you to beautify the map.

  1. Get the DEM files (for eg. from https://earthexplorer.usgs.gov/)
  2. Clip it if necessary. This can reduce the computation time.
  3. Reproject the lat/long DEM file to metric base e.g. UTM (this is essential for any area based analysis).
    Raster>Projection> Wrap
  4. Make sure the projection coordinate used in DEM and your data frame matches.
  5. Fill the projected DEM for any inconsistent data.
    Processing toolbox>SAGA>Terrain analysis(hydrology)>Fill sinks (wang & liu)
  6. Calculate Strahaler order for the filled raster. This is necessary to know the river lines. The intake location should lie exactly on the river line shown by Strahaler .
    Processing toolbox>SAGA>Terrain analysis(channels)>Strahaler order
  7. Delineate the catchment using upslope command. Choose the X,Y coordinate lying on the line calculated by Strahaler .
    Processing toolbox>SAGA>Terraine analysis>Terrain analysis(hydrology)>Upslope area
  8. Using Raster to vector convert the delineated raster to vector.
    Raster>Conversion>Raster to vector
  9. Go to attribute table, add new field with formula “area”. The area is calculated in square meters.

 

Financial side of Akashi-Kaiko bridge

Akashi-Kaiko bridge is world’s longest suspension bridge (total length= 4km; suspended length=2km ). It is located in Japan connecting two main islands called Honsu and Sikoku. Recently I had chance to visit this bridge. Yes, as a civil engineer I can say this bridge is awesome, magnificent and beautiful. During construction, this bridge suffered a big earthquake that increased its span by about 0.80m than original length.  Thanks to Japanese high tech and safety measures, only 6 injury occurred to build this bridge and no one lost life during 10 years of construction works.

Besides its technical marvels, i was also interested in hidden parts – financial and economical side of this bridge.

Wikipedia mentions – “The total cost is estimated at 500 billion yen, and is expected to be repaid by charging drivers a toll to cross the bridge. The toll is 2,300 yen and the bridge is used by approximately 23,000 cars per day. At 2300 yen/car annual revenue would equal 19.5 billion yen. Given the interest expense on 500 billion yen, this bridge will never be repaid. But annual revenue is around 4% of investment, so with near zero interest rates in Japan, the bridge will pay for itself in 30 years, plus enable the growth of the overall economy in the region.”

I had doubt on the wiki’s statement. So, I did some research with authentic publications. After some study i found that, wiki is partially correct.

The bridge was build during the times when roads and trains were under Japanese government control. 67% of the investment for the construction of this bridge (and the related highway) was done by central government and rest were divided between 10 other local governments. Interestingly, all the government investments were at 0% interest rate.

In addition, loans were taken in the form of government guaranteed bond, private sector bond and pure loans. Similarly, Japan Railway also had small investment (although there is no train way in Akashi-Kaiko bridge, there is train ways in other bridge connecting two islands which same company operates, hence the loan).

How the investment will be paid back?
In 1990s, there was change in government policies and many government bodies were privatized. This resulted in complicated system of revenue collection and payment system for the bridge. Railway has to pay to the Highway company for leasing the train ways. In addition, the highway itself collects the toll. The total revenue is to be split up for loan payback and maintenance and operation of bridge.

Figure below shows the summary of payment method.

As wiki mentioned earlier, the cost of bridge is so huge that even with cumulative traffic tolls, the revenue will not be sufficient to payback  the normal interest rate. However, as most of the investment was done by government at 0% interest rate, the pay back period of this bridge is estimated to be about 45 years (including cost of highways).

The fact remains that investment by government in such massive projects becomes mandatory if we want to develop the society as a whole.

Just side note: Government of Japan has taken massive loans from World Bank for infrastructure development. However, most of the loans were re-payed in 1990s and now there is almost no loans left to be repaid.

Reference:
http://www.jb-honshi.co.jp/english/library/pdf/bridges.pdf