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Johnson, Robert E. Liang, Erwin Wen-Ti 2011-05-07T12:14:52Z 2011-05-07T12:14:52Z 10000-01-01 1991 A finite element simulation, based on Barone and Caulk's model, is developed to study the compression mold filling over three-dimensional curved surfaces. The effects of charge thickness and surface curvature on the pressure and velocity distributions are examined. In solving the velocity-pressure type equation, an element-based penalty method is implemented into the simulation. This approach shows great accuracy and efficiency as compared with the mixed formulation and a iteration scheme. The full Barone and Caulk model gives accurate predictions of filling patterns for thick charges. In thin charges, a special numerical treatment of the full Barone and Caulk model is developed by adding artificial elongational viscosity. Finite element results show that this model produces better accuracy in velocity as well as velocity gradient compared with the Hele-Shaw formulation, which is used by most molding simulations. A new technique is developed for tracking the moving flow front, using a fixed finite element mesh which models the part geometry. For each time step, temporary elements and temporary nodes are generated within the filled region of any element intersected by the flow front. This scheme allows a smooth representation of the flow front and the imposition of exact boundary conditions on the flow front. Other advantages of this scheme are flexibility in mesh generation and the local mesh refinement. This simulation accurately predicts the flow patterns and knit line locations. The formation and motion of knit lines can easily be tracked by this scheme. A three dimensional shell-like mold cavity is mapped from the physical domain to a planar cavity of uniform thickness in a transformed domain. Two-dimensional flow equations are formulated in the curvilinear coordinate system associated with the mid-surface. The mold filling simulation is performed in the transformed space, as metric tensors and Cristoffel symbols for the surface are provided. The solutions can be mapped back onto the three-dimensional physical space, since all the quantities in the two domains has a one-to-one correspondence. Made available in DSpace on 2011-05-07T12:14:52Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9124452.pdf: 4932288 bytes, checksum: 75befb9fe29309e5346404c4d0242f94 (MD5) Previous issue date: 1991 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:38:39Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:16:08-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission ETDs are only available to UIUC Users without author permission U of I Only AAI9124452 (UMI)AAI9124452 http://hdl.handle.net/2142/19673 eng Copyright 1991 Liang, Erwin Wen-Ti Applied Mechanics Engineering, Mechanical Plastics Technology Compression mold filling simulation for thick, nonplanar parts text Mechanical Science and Engineering Mechanical Science University of Illinois at Urbana-Champaign Dissertation Ph.D.