Mesh Topology: The target CAD geometry for meshing includes errors that are of the CAD data itself (sliver faces, intersections, non-manifolds, etc), and errors that occur during data translation from the CAD to the meshing kernel. TSV-Pre automatically removes these errors using a unique technology, so that a meshable geometry is obtained without damaging the CAD data.
The mesh data can be modified or changed by basic operations such as merging, splitting, swapping, and node move.
Generally, users needed to return to the CAD data and modify the original geometry in order to remove bad stretch elements, but now TSV-Pre has realized a completely automatic modification method for most actual models. This is a key feature of TSV-Pre.
Also, if second order elements with midnodes are used, TSV-Pre has a function that projects the midnodes on the CAD geometry.
In TSV, the below two assembly methods are available.
- Assemble components that have already been meshed.
- Assemble CAD data that will be meshed afterwards.
For example, the mesh can be regularly configured by defining the same number of elements for the cylinder circumference, height, and opposite side of the quadrilateral. Generally, the user must define the mesh size in order to create a mapped mesh, but TSV-Pre provides a function that automatically searches for the 4 sides and creates a mapped mesh.
The groups can editted (add, delete, etc) at the user’s will.
Also, you can export the defined group itself, or the model, face, edge, element with the defined group deleted.
It is especially noteworthy that faces are combined complexly in an actual solid model, and in most cases, manual corrections were needed for missing faces, poor mating, or mistakes in thickness measurements after automatic midplane extraction.
Many users believed that the overall time required for analysis will be actually shorter by extracting the midplanes manually, instead of correcting errors of automatic extraction results. This is why the automatic midplane function has not become familiar until now.
TechnoStar’s new function performs all operations automatically, from CAD data to mesh generation. Traditaional problems, such as missing faces, poor mating, or mistakes in thickness measurements do not exist. Also, midplanes can be extracted even if the CAD data includes some flaws.
This new function from TechnoStar can be used to drastically improve our efficiency in strength, vibration, impact and resin flow analyses
Just like in TSV-Post, any area of the model can be displayed at the user’s will.
Now any information , for example the inner geometry of the structure or information on the solid mesh elements, can be observed as you wish.
For example, meshing an automobile engine power train generally requires 1 week to 1 month.
With TSV-Pre, an engine head model can be ready for analysis in 1 to 2 hours, including clean-up.(All major CAD formats are supported.)
Even for assembly models, the FEM model data (linear static, nonlinear, NVH) for an engine power train can be prepared in 1 to 2 days.
|Supported analysis types||Structural analysis, fluid analysis, crack propagation analysis, etc.|
|CAD interface||Pro-E, Catia V5 (VRML), I-DEAS (IDI), Parasolid, ACIS, STL, BDF, CoCreate OneSpace Modeling
* Assembled CAD geometry can be imported.
|Elements||First and second order triangle elements, quadrilateral plate elements, first and second order tetrahedral elements, hexahedral elements, pentagonal elements, gasket elements, RBE elements, Stress_MPC elements, ontact elements, bar elements, etc.|
|Automatic mesh generation||Triangle elements, quadrilateral plate elements, surface mesh, volume mesh.|
|Automatic assembly function||CAD geometry, FEM mesh geometry, automatic extraction of shared surface, assembly model creation.|
|Display||3D fast display using OpenGL, cross section display by the 3D mouse, etc.|
|Operations||Multi-scanning by 3D mouse, Picking (by element, node, face, body, arbitrary point), Rotation, Zooming, Reversal of model, Translation, Measurements (of distance, angle, area)|
|Data processing||Grouping, sorting|
|Solver output||Nastran .bdf, ADVC, Abaqus .inp files, etc.|
|Geometry export||vdb (TSV original format), bdf|
|Image output||Copying to the Windows clipboard, saving in BMP, JPG, or PNG format|
|OS||Windows2000 Professional SP4 or higher
– WindowsXP Professional SP2 or higher
|CPU||Pentium4 2.4GHz or higher|
|Memory||1GB or higher||2GB or higher|
|HDD availability||Application: 400MB
– Model: 20GB or higher
(Depending on model size)
– Model: 40GB or higher
(Depending on model size)
– VRAM: 128MB or higher
– VGA card supporting OpenGL
– VRAM: 256MB or higher
– VGA card supporting OpenGL
|Cylinder bore inner layer mesh||5mm|
|Overall mesh size||8mm|
|Number of nodes||740,000|
|Number of elements (Tet10)||110,000|
Ship model (Cut model of a tanker bulk area)
|Number of nodes||130,000|
|Number of elements (Tet4)||510,000|
|Note: 57 parts/119 faces were automatically assembled and meshed.|
Technostar strives to develop an original CAE software that can truly contribute to the strengthening of product development capabilities of our customers in the manufacturing industry.
This article introduces a user example that was provided by Nissan Motor Co., Ltd., in which the total analysis time required for the analysis process was reduced by 80%.
Source : Automotive Information Platform
MarkLines Co., Ltd.(www.marklines.com) 2006.05
Extracted from an automotive solution report
The expanse of CAE use in component design
– A system develpment application to promote CAE for designers
Nissan Motor Co., Ltd. (Transmission vibration stress prediction system)
In order to reduce the time and costs for transmission design, Nissan is shifting its development process from a test oriented process in which prototyping and physical tests are repeated in order to decide the specifications, to a design oriented process, which uses computer simulation to identify problems in the early stage of development (Figure 7).
Transmission vibration stress is caused by strain amplification due to the bending resonance of powerplants, and affects the durability of the transmission.
The traditional performance design only focused on the bending resonance frequency, and the vibration stress, which is the final evaluation item, was detected by physical tests. In some cases, the cycle of prototyping and physical testings was repeated several times until the problems were solved.
In order to achieve more efficiency for analysis work, Nissan developed a new analysis system, as well as the transmission vibration stress prediction technology using large scale structural analysis models (Nissan technical paper, 2006).
In traditional performance design, a normal mode analysis of the powerplant was performed using simplified shell models. In this application example, the stress concentration area needed to be identified in detail to obtain the transmission vibration stress. Therefore, the box geometry was modeled using 300,000 solid elements (Figure 8).
There is hardly any difference between the bending normal mode results of the two models, which indicates that shell elements have sufficient accuracy for normal model analysis. The solid model result shows that the crack location from the physical test coincide well with the stress concentration area obtained from the vibration stress analysis. In order to match the absolute stress value and the actual measurement value, the element size must be smaller than 1mm. However this will result in an immensely long calculation time.
Studies confirmed that the realistic method is to perform vibration stress analysis using a normal mesh (8mm), after which the area of stress concentration is remeshed using a fine mesh (0.5~1mm).
Although this method enables the estimation of vibration stress, there still remains a problem for its application to development projects, due to the long analysis time. Therefore, a new system was developed to largely reduce the analysis time.
The analysis flow of this estimation method is: (1) Creating the analysis model -> (2) Assembly-> (3) Normal mode analysis-> (4) Vibration stress analysis-> (5) Stress evaluation-> (6) Remesh-> (7) Assembly-> (8) Vibration stress analysis-> (9) Stress evaluation. Steps (1), (5) and (6) make up over 80% of the total process.
A meshing software with outstanding automatic meshing function was introduced in order to reduce the time required for creating an analysis model based on 3D CAD data.
A stress evaluation software was developed that can automatically detect areas of stress concentration, stress values, and areas above a defined threshold, in order to reduce the time required for evaluating vibration stress analysis results. Also, an integrated function of meshing and stress evaluation applications was developed that can automatically generate a fine mesh for the areas that were detected, in order to reduce the time required for remeshing areas of stress concentration.
By developing this new analysis system, Nissan managed to reduce their total analysis time to 40 hours, which is 20% of the previous number of man hours.
Written by Mizuho Fukuda, CAE consultant