The error relates to initial maturity which was introduced in version 6.17 in April 2020.
The results are correct immediately after the calculation but when a job is saved and then retrieved again, any initial maturities are reset to zero for the volumes that have been cast later than the time zero.
As a consequence maturities, strengths and tensile strength utilizations also become incorrect.
Isoplots are displaying the wrong results while the diagrams concerning min/max/average are still showing the correct results.
However, if the simulation is continued based on a job which is reloaded also the subsequent results are not correct.
The error is corrected, and the correct results are obtained by calculating the relevant models again.
Features identical to version 6.17 but licensed via the Internet.
Instead of a USB-license key, login information is needed.
Saving and loading of job files are optimized. When existing job files are loaded they are automatically updated.
The material properties of hardening concrete are described as a function of maturity. If the maturity of the fresh concrete when casting, is significantly different from the starting point of the function (this is often the time of mixing), then an initial maturity can now be indicated. This can apply in situations with a long transport time. The initial maturity is calculated by hand on the time period before casting.
In several cases, the use of initial maturity does not significantly change the results. However, the use of the initial maturity increases the consistency between the simulation and the real hardening process. The initial maturity is useful when e.g. having a daily variation in the boundary conditions or changes in the curing measures at specific times. Also, when monitoring temperatures, the use of initial maturity may lead to a better agreement with the simulation. Furthermore, the initial value can also include a contribution from the time used to place the concrete in the volume.
The coordinate system of the STL-Data is considered as the (r, s, t) system.
After loading of STL-Data, the minimum and maximum values of the (r, s, t)-coordinates of the volume are shown as perceived by b4cast, now including all digits.
It is now possible to position the (r, s, t) system in the global b4cast system (x, y, z) as follows:
If the (r, s, t)-coordinates are representing geographical data with very high values, it may result in loss of accuracy of the calculation results. Option b is useful for reducing the coordinates.
If several volumes are referring to the same geographical origin, the Copy-feature in option c makes it easy to position the volumes following a volume placed by option b.
The method of mesh generation has been made more robust. This may result in a slightly altered FEM-mesh. That is the explanation if your results are not exactly as they usually are.
In the printed output, user defined texts that are too long for the tables, are now truncated.
This update provides a more efficient display of isocurves and 3D plots.
In addition to the increased efficiency, a feature suitable for particularly large models has been introduced. Pressing the “q” key while moving the 3D model suppresses the effect of hidden surfaces and speeds up viewing.
Previous versions of job files can be loaded into the new software version.
This release may result in a slightly altered FEM-mesh around the casting joints. That is the explanation if your results are not exactly as they usually are.
It is now possible to remove a volume as part of the simulations. The feature is used to model match casting in prefabricated segment construction. This also allows for modeling removal of temporary support structures.
Until this version external load models have worked as follows: A volume is applied to the load changes that occur after the volume is cast. This means that if the load was defined from the start and kept constant, no load was applied.
From this version: If there is a load on the cast from the beginning, this is applied.
A new method has been introduced to improve preservation of boundary conditions, when geometries are changed.
By visualizing deformed construction in 3D, it is now possible to reset the factor of the displayed displacements to a default value. The value is determined so that the maximum occurrence of displacement (throughout the simulation period) is shown as 5% of the extent of the construction.
It is now possible to apply boundary conditions that allow for evaporation and condensation to be considered.
In the simulation it is assumed that the relative humidity of the surface is 100% RH. This can be obtained by keeping the surface wet, by wet covering (evaporation) or by means of a steam curing chamber (condensation). The ambient conditions are defined by the user by models for temperature, wind speed and relative humidity.
The Heat Flux from evaporation (cooling) and condensation (heating) is included in the thermal analysis by means of the difference in water vapor pressure on the concrete surface and in the surroundings.
The amount of evaporated/condensed water is also calculated. If a surface is not kept wet, the analysis can be used to assess, whether requirements concerning rate of evaporation or total evaporation, are met.
These results are presented in a table, for each surface as a function of time. In a future version these results will be presented like the other types of results.
The new boundary conditions can be found on a new tabbed pane. Flux, radiation temperature and radiation transmission coefficient have also been moved to the new tabbed pane.
It is now possible to change the time in the 3D window while you are managing volumes, boundary conditions and pipes.
In relation to calculation of Arrhenius maturity the internal temperature unit is now converted to Kelvin by adding 273.15.
Until this version 273.0 was added.
That is the explanation if your results are not exactly as they usually are.
Sometimes the simulation did not follow the defined timestep model. This error has now been corrected.
Zoom on volumes cast at different times, did not work properly. The error was introduced in version 6.12 but is now corrected.
From version 6.11 it was a problem if the default decimal separator was different from “.” in Windows-Control-Panel->Region->Language. This is solved now.
In order to save memory, it is possible to divide a long simulation period into separate b4cast jobs by means of the feature “Discard previous results”. Each job is representing a subperiod.
When a job is saved, the initial maturities and the progress of temperatures and stresses are stored. When the job afterwards is loaded, the progress of maturities, strengths and exploitations are calculated as a part of the loading process. This calculation is based on the initial maturities and the stored temperatures and stresses. If the “Discard” option has not been used, the initial values of the maturities are zeros. If the option has been used, the maturities are not zeros.
However, for jobs where the previous results have been discarded, the initial maturities are erroneously reset to zeros, if the job is loaded again. Therefore, the calculation of maturities, strengths and the exploitation become wrong. (Diagram curves may show that the values are OK, but they are not representing the values which is used in further calculations. These values are seen on iso-plots).
The temperatures and the stresses are correct. However, if this job, after having loaded it, is used for analysis of the next subperiod, all subsequent results will not be correct because the material properties are depending on the maturities, which are wrong.
How wrong are the results then?
If the time period between the reset of maturity (the beginning of the subperiod in question) and the beginning of the next subperiod is so long, that the material properties are close to their final values, the effect of the reset of maturity is small.
A recalculation with this new version can illustrate the effect of the error in specific jobs.
If the jobs have not been loaded between the simulation of subperiods all results are correct. However, if you load the jobs afterwards, maturities, strengths and exploitations are not correct. Temperatures and stresses are still correct.
This error was introduced in version 6.00 and is now corrected.
If materials without tensile or compression strengths are present, there is a problem with the Diagrams.
When defining curves with strengths or exploitations, the curve symbol (a, b, c, etc.) is not placed next to the table cell where the “+” sign is selected.
This error is corrected.
The storing of results has been optimized, in order to save memory and time.
The Heat of Hydration is defined as released energy per weight-unit of the Powder Content. The Powder Content is the amount of powder per volume-unit of concrete.
The Powder Content can take any value, powder content or cement content, if the Heat of Hydration is based on the same type of content.
In the new version it is possible to specify if you want to calculate the Heat of Hydration based on Powder Content or Cement Content. For unknown reasons the value has until now being presented as Cement Content on printed output. The printed output is in the new version consistent with the input definition.
When drawing the b4cast model in the right upper windows, the software automatically selects the perspective. It is not always resulting in appropriate images. The strategy for choosing the perspective has been changed.
When making the geometry and the element mesh, sometimes problems can occur. After 30 seconds efforts to make the geometry you will now be asked if you want to continue. More complex geometries may need more than 30 seconds to complete. During the mesh generation, you can interrupt the process.
To solve the problems, a new parameter has been introduced in the Setup window. Meshing is done by means of a bounding box which is enclosing the structure. As default is used a box of a magnitude of 100 times the extent of the structure. In case of problems with generating the element mesh, try another value, 10 or 1000 e.g.
When entering Point-supports, after having defined supports or loads on faces, a direction was not always set.
If you have Enabled or Disabled developments in a Material, this is now covered by the Cancel feature.
After load of STL data, it is shown how b4cast has stored the extreme values.
It is now possible to store and visualize displacements. This can be indicated in the Setup Window.
The visualization is, as for the other types of results, iso-curves and diagrams.
When visualizing displacements, the 3D picture of the geometry is shown with deformations.
A new type of units to be used with displacements has been introduced.
When structures are not statically determined, b4cast is automatically providing the necessary supports.
This is not always conveniently when displacements are visualized.
In order to let the user define the zero points for the displacements a new feature with point supports has been added.
Please notice that b4cast does not provide any supports automatically, when the user manually is defining point supports.
January, 2018, Updated February 2018
Possible error in calculating stresses when using Fahrenheit
This issue is only relevant in stress analysis in combinations with Fahrenheit.
In the System Units, the unit label is shown as "-" when defining the thermal expansion coefficient. The unit in question should have been [1/Celsius].
The erroneous label may lead to the misunderstanding that the coefficient you are specifying, automatically is converted to the temperature unit you have chosen to work with.
If you are working with Celsius or Kelvin degrees, there is no problem because they are compatible with the internal unit system.
When using Fahrenheit, as for all other variables, you have to define the thermal expansion conversion factor yourself. However, the label "-" makes it easy to overlook the need for conversion. In that case the calculations have been made with thermal expansions which are too high.
The conversion factor between [1/F] and [1/C] is 9/5 = 1.8. (In January 2018 it was erroneous indicated as 5/9 = 0.5555556)
The erroneous label is corrected in this version of b4cast as regards the System Units.
However, if you are using Fahrenheit please specify the conversion from [1/F] to [1/C] as indicated above and check your values afterwards.
If you have saved a system of units as a User Default, please save it again after the correction.
When saving shields, materials, pipes etc. in an library, an error message was generated even, there was no error.
More errors are corrected when saving Diagrams in a text file:
If models, loaded by means of STL files, have very small surface elements a warning is generated.
If earlier defined views of exploitations were obsolete it was resulted in an error.
When a volume is completely embedded in another volume is now detected.
When selecting all surfaces sometimes nothing was selected.
Internal improvements on the use of STL files.
Inconveniences on converting units are corrected.
Optimization of calculation procedures.
Correction of minor inconveniences.
The equation solver has been replaced by a faster version.
It is possible to load job-files from version 5.x.x.
However, the results are discarded.
In the new version are the results saved in a separate file, “jobname”-results.dat. The model is saved in “jobname”.b4c. When you exchange the model with someone, you can choose to omit the result file, which is often very large.
As an alternative to modelling volumes (solids or voids for holes/chamfering) by means of specifying two cross sections and a length, it is now possible to load STL-files created by CAD software (binary or ASCII-format) or from manual entering (ASCII-format).
Editing of boundary conditions now have new options:
Furthermore, tries the software tries to preserve the boundary conditions, when changes are made in the geometry.
When specifying convective boundary conditions directly with coefficients (not using shield and wind speed), it is now possible to define the time points, relatively to the time where the concrete is placed.
Cooling pipes/heating wires are shown graphically, simultaneously with specifying the coordinates. Graphic selection of a node identifies the corresponding row in the coordinate table. The node, in the active row in the table, is presented graphically.
It is now possible for each user to store a set of preferred units. When creating new b4cast jobs, the user defined units are used by default.
Paths to folders with job-files, materials, shields, cooling pipes etc., are now stored automatically.
Decimals on floating point values are no longer formatted on input values.
Zoom in the graphic windows have been done by framing by means of the right mouse button. Now it is also possible to use the mouse wheel. On isoplots and diagrammes you can now also pan.
Some of the existing features have been changed because of the new features.
The table below shows all features.
All operations are using left mouse button, except unzoom.
|Geometry||Mouse click selects volumes, pipes/wires.||Dragging with left mouse button pressed||N/A||Framing with Control key and dragging with left mouse button pressed.
|Mouse click with right button.
|Boundary Conditions||Mouse click select/deselect single surfaces.
Dragging the mouse over surfaces with Shift and left mouse button pressed, copies selection/deselection to the surfaces.
Mouse click with key “a” pressed selects all surfaces on volume.
Mouse click with Shift and key “a” pressed selects all surfaces.
|Isoplot||Mouse click defines a point for diagrammes||N/A||Dragging with left mouse button pressed|
|Diagrammes||Mouse click on the curves points looks up the position on the isoplot.|