Shape Optimization of Engine Block (from India)

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Areas covered:

  • Geometry Abstraction for FE modeling.
  • Automatic Mesh Generation.
  • Free-shape optimization with Stress constraints.
  • Use of manufacturing-constraints.
  • Design interpretations of FE results.
  • Transfer of an FE model to a CAD modeler for post-optimization detailed-design.

Description of the Problem: An assembly model for the engine of a model aircraft has been proposed. Any design changes must only be incremental – structural changes are ruled out by the project-deadlines. Instead, the designers have asked that attention be paid to the outer profile of the engine block. The radii chosen at the CAD stage were not based on any calculations. The goal now is to start with the given shape and check if changes to the shape can reduce stresses. Engine design is multi-disciplinary, since heat transfer and fluid flow (for combustion) are at least as important as structural design. There are also forces that the engine experiences because of the movement of the piston. It may seem that a topology optimization on the engine block to suggest material layout is a good idea, but there are thermal considerations that are important, and these have not been provided to us. Remember that thermal heat capacity of the engine, its heat-dissipation characteristics, etc. are more important than weight-reduction. There is no functional basis for the outer-profile of the engine block. We can only work with the exterior, and with areas away from the mounting and assembly points. Ideally we should carry out an analysis of the entire assembly. Unfortunately that is not within the scope of the design. In actual usage, a range of allowable values for subsystems (stresses, natural frequencies, etc.) should be provided to the component designer by the system-integrator. In the absence of these, we will concentrate on the behavior under static loading.

The Solution-Summary can be viewed on any computer that has an AVI or VLC  player (e.g. VLC media player 2.0.3) installed.

Right-click on each of the links below, choose “Save As” and save the files to a folder on your computer. Then use a “zip” application to extract the contents to your folder.

After you extract the files, open the HTML file titled Os_EngineShapeDesign.html and use the menus to access the instructions in sequence.

Alternate links

Data Import
Loads and Analysis + Loads and Analysis z01(rename jpg to z01)
Meshing + Meshing z01(rename jpg to z01)
Optimization Solution
Optimization Setup