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Boundary Element Analysis at Caterpillar

Boundary Element Analysis at Caterpillar. Ling Pan Caterpillar Inc. EZBEA. Easy Boundary Element Analysis Originated from ‘70’s code at Kentucky State Owned & enhanced significantly by Caterpillar Model external boundary only Meshing is much easier, especially with details & small holes

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Boundary Element Analysis at Caterpillar

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  1. Boundary Element Analysis at Caterpillar Ling Pan Caterpillar Inc. NIST Green's Function Meeting 2002

  2. EZBEA • Easy Boundary Element Analysis • Originated from ‘70’s code at Kentucky State • Owned & enhanced significantly by Caterpillar • Model external boundary only • Meshing is much easier, especially with details & small holes • Accurate with coarse triangles, quads NIST Green's Function Meeting 2002

  3. Strength • Excels on Geometry with Complicated Details - Still difficult to tet-mesh - “Easy” to surface-mesh Looking Inside Intersecting Holes Brake Stand for C9 Engine NIST Green's Function Meeting 2002

  4. Applications • Engine components • Fuel injector • Crankshaft • Powertrain components • Gear • Shaft NIST Green's Function Meeting 2002

  5. Challenges • Longer solve time compared to FEA analysis • Nonlinear (contact) analysis • Not suitable with thin body (fabricated) structures NIST Green's Function Meeting 2002

  6. EZBEA+ • EZBEA+ - provides integration with Pro/Mesh EZBEA Menus NIST Green's Function Meeting 2002

  7. EZBEA Capabilities • Material • Isotropic, linear, 1 per subregion • Symmetry: • planes of geometric symmetry • planes of loading symmetry/anti-symmetry • Analysis types • steady-state heat conduction • static thermoelasticity • beam section properties • Domain types • planar • axisymmetric • general 3D NIST Green's Function Meeting 2002

  8. EZBEA Capabilities • Loading and Boundary Conditions • Only linear, static loads and boundary conditions • point load constraints • edge pressure constraints • surface pressure constraints • surface displacement constraints • Loads and boundary conditions in nature have area associated with them. • A true point load is impossible • A knife edge constraint is impossible • These loads would result in infinite stress NIST Green's Function Meeting 2002

  9. An Example: 9881 nodes, 20 hours on HP C240 NIST Green's Function Meeting 2002

  10. Current Models size vs. Time Plot on HP C240 NIST Green's Function Meeting 2002

  11. Speedup NIST Green's Function Meeting 2002

  12. Future Work • Eliminate the physical limit on number of elements and nodes • dynamic memory allocation • scratch files • accuracy issue when elements get smaller(double precision) NIST Green's Function Meeting 2002

  13. Future Work • Solver improvement (performance issue) • improve current solver (direct solver, O(N3)) • iterative solver (O(N2)) • Caterpillar has looked into this before • Does not always converge for large problems NIST Green's Function Meeting 2002

  14. Future Work • Multipole accelerated BEM (O(NlogN) operations) • significant performance gain • has to use iterative solver • convergence for large problem questionable • would involve significant work NIST Green's Function Meeting 2002

  15. Future Work • Continue gap, contact work • capability to analyze assemblies • implement line integral for thinner structures • improve accuracy NIST Green's Function Meeting 2002

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