FREQUENTLY ASKED QUESTIONS
FREQUENTLY
ASKED
QUESTIONS
Select your topic:
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Is there a limit to the total number of elements or nodes that the 2-D or 3-D version can handle?
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The number of element is only limited by the amount of RAM you installed on your PC or laptop. The arrays allocation for the matrices are done on the fly.
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Why can???t I start drawing lines to create my finite element models after installation?
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GeoFEA model interface uses DirectX runtime libraries for drawing input. If you are not seeing the grid lines on the interface windows, your computer might not have the required DirectX runtime libraries installed. You may download it from Microsoft website.
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Why can???t I get the Find Face function to operate after creating the model geometry?
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You need to ensure that the polygon is closed meaning the lines are joined ends to ends and there are overlapping lines in the geometry. After you had selected the faces to operate on, click on ???Find Face??? to get the command option at the bottom of the application window. Tap ???Enter??? on your keyboard to create face(s).
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How do I detect any overlapping line, face or volume objects during model creation?
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You can right click your mouse pointer over all the lines or faces to check which one gives you selection list with line, face or volume objects. Those that allow you to pick from two or more objects are the ones with overlapping objects.
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Does GeoFEA has the capability to automatically re-discretise to generate a new mesh whenever a new node or 1-D element is inserted into an existing mesh?
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GeoFEA will only re-mesh your model if prompted to. It will automatically detect the additional lines included in a domain. The process is not fully automatic as some users may want to couple a part of the line to the solid elements instead. This flexibility is required during modelling of bonded and unbonded length of soil nails.
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How do I model a thick structural wall using quadrilateral or hexahedral elements instead of using line elements?
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Select the domain to be replicated. Do a ???Move??? operation with the copy option enabled to produce an identical copy of the domain. Use the same coordinate for both the first and copy point to place the copy of the domain at the same location. Select the copy and exclude it from the current view of the insitu stage. Reassign the copy with the appropriate material properties. Done.
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Is it possible to allow the time units to accommodate minutes, hours, days, weeks etc. rather than be restricted to seconds?
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No, the software only accommodate seconds as time input. We may consider that in future release.
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What are the parameters required for interface elements in GeoFEA?
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GeoFEA does not have interface elements for both 2D and 3D versions as we understand the inherent problem with interface elements. We also noted the difficulty involved when deriving the correct parameters when we uses a more complex formulation for an advanced interface elements. In view of the above, we had been recommending alternative to the use of interface elements. The interface elements are usually used to simulate the reduced friction between the wall or pile elements and the soil. Therefore, we recommend applying a friction factor ranging between 1/3 and 2/3 of the soil friction angle as the friction angle for the set of relatively thin soil elements adjoining the structural elements. This will mimic the soil-structure interface behaviour. Typical values of this friction factor can be found in NAVFAC standards. Other parameters will follows that of the soil elements adjacent to them. The advantage to this is the zero thickness of the interface element causing numerical instability can be avoided. The derivation of the interface properties is much easier and these values can be referenced for different frictional behaviour between two materials according to NAVFAC standards. The disadvantage is the use of more elements and degree-of-freedoms in the computation. There is an inherent difficulty in specifying tension cut-off value for soil. .
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Should I use Absolute or Total Head Pore-pressure fixity for the exposed surface in an excavation?
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Using Absolute Pore-pressure for the exposed surface is not appropriate in an excavation analysis. Total Head pore pressure fixity should be used instead. The reason being that we are unable to know how much the absolute pore pressure change will be at each excavation step prior to each step.
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Is there an option to display the Absolute Pore-pressure contours?
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We do not output Absolute Pore-pressure. What most users will be concern with either the total pressure or if there is still excess pore pressure to be dissipated.
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Is there an option to display the Deformed Shape/Mesh in the Post-processor?
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Yes. The Deformed Shape option can be found in the Results tab under Post-Process: Displacements > Displacement norm. It will appear as a Deform shape toolbox.
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Does the Post-processor display outputs for the individual analysis Increments?
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Yes, you will have to use the scroll button as shown below each step???s name.
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Is it possible to display the deformed mesh overlaying the original undeformed mesh?
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It is not possible to overlay the deformed mesh over the original undeformed mesh currently. To show deformation from the original mesh, we can use the vector plot.
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Can the mesh be displayed with element or/and node numbers in both the pre- and post-processor screens?
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We do not provide the facility to show the element or node number. All the elements and nodes will undergo an optimising procedure thus the ordering will seem haphazard thus it may not be useful for the user to search for one element among the rest. We provide the facility to identify the element with element number.
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Does the software produce a readable output file of the analysis results?
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The software is able to output readable files for line plots.
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Will a full comprehensive operating manual be available when I purchase GeoFEA?
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We currently have no plans for a comprehensive operating manual. We will provide instructions through video demonstrations which we think is more effective than printed words.
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