Fully-Coupled Multiphysics Finite Element Simulation

Signs Your Finite Element Analysis
Needs Improvements

  • Utilizing a static mesh to model simulations featuring moving interfaces or boundaries.

  • Relying on frequent remeshing to capture severe material deformation or dynamic fluid flows.

  • Employing decoupled (sequential) or loosely-coupled (partitioned) solvers to evaluate thermal-fluid-structural interactions, including phase change.

Limitations of Fixed Mesh

A fixed mesh can not deform or dynamically conform to advancing boundaries or the shifting interfaces between fluid and solid. If a FEA relies on a rigid mesh during deformation and/or flow simulation with moving boundary, the predictive accuracy suffers in three critical ways:

  • Zigzag Boundary: Because the mesh cannot deform to match the true material boundaries, the software tracks the advancing fronts by toggling individual elements on or off. This crude discretization forces smooth, curved boundary into a jagged, staircase-like profile, compromising local geometric accuracy.

  • Boundary Condition Degradation:

  • Distributed Boundary Conditions: Kinematic and kinetic constraints must be averaged and applied across stationary nodes instead of aligning precisely with the physical moving surface.

  • Mass Conservation Errors: As element toggle state at the flow boundaries, small amounts of material may artificially appear or disappear, violating basic mass conservation principles.

  • Suppressed Flow Physics: By smoothing out these vital localized gradients, the fixed grid fails to capture the core physics near the boundary, such as the "fountain flow" phenomenon—the essential process where hot core plastic rolls outward toward the cold mold walls in polymer injection molding.

Advantages of Scienmulate’s
Boundary-Tracking Method

  • Adaptive Geometric Tracking: Dynamic nodes seamlessly adjust to the evolving geometry of the moving boundary.

  • Exact Boundary Condition Imposition: Physics-based boundary conditions are applied precisely at the physical interface rather than being approximated.

  • Rigorous Interfacial Balance: Forces, energy and mass balances are accurately preserved across the transitioning boundary.

  • Enhanced Numerical Stability: The approach stabilizes nonlinear iterations, mitigating numerical oscillations and preventing catastrophic runtime errors.

  • Mesh Integrity Preservation: The method maintains a physically accurate and well-shaped mesh layout, preventing element inversion or severe distortion.

  • Automatic Tracking: No user-defined mesh velocity is required.

Comparison of Solvers for Thermal-Flow-Structural Interactions

When a fluid and a solid strongly influence one another—such as during a phase change—the physical phenomena become deeply interdependent. Accurately modeling these interactions requires specific numerical solution approaches, which vary significantly in execution, complexity, and precision:

  • Sequential (Decoupled) Solver:
    Thermal flow and structural stress analyses are computed in a strict linear sequence. While this method is the easiest to implement, it provides the lowest accuracy because it fails to capture real-time feedback between the physics.

  • Partitioned (Loosely-Coupled) Solver:
    The software resolves the fluid and structural equations independently, passing force and boundary shape data back and forth across the interface at each step. This approach is difficult to implement but yields higher accuracy than a sequential solver.

  • Fully-Coupled (Monolithic) Solver:
    Fluid and structural equations are solved simultaneously within a single, unified mesh matrix. This methodology is exceptionally difficult to implement but delivers the highest possible accuracy for highly coupled multi-physics problems.

Scienmulate’s Innovations

  • Accurate Boundary Tracking: In our FEA, the mesh boundaries move in sync with the material boundary, matching its curved shape accurately and capturing the force, energy and mass balance across the transitioning boundary accurately.

  • Mesh Integrity Preservation: The mesh quality is automatically preserved, leading to stabilized simulation and faithful prediction.

  • Fully-Coupled Multiphysics Simulations: The heat transfer, fluid flow, phase change and structural analyses are fully coupled, capturing the true dynamic interactions between fluid and solid structure.

Current Status

  • Our FEA software is under development.

  • Please leave your contact information if you are interested to apply our FEA in your applications.