Implicit and Explicit Simulations

Determining when an implicit or explicit analysis simulation is appropriate for a given problem is essential in order to produce accurate results. Additionally, time and computational expenses must be evaluated when determining the best numerical method. DJHEC has been utilizing implicit and explicit finite element analysis for over 20 years and provides customers with guidance on which method is most appropriate for their situation. Typical simulations when implicit analysis is appropriate include:

  • Static Structural
  • Steady State
  • Modal
  • Harmonic Slow Speed Dynamic Events

These types of simulation are well characterized by implicit numerical methods. Results are produced in an iterative process. The implicit method allows for larger computational time steps without typically being computationally expensive. Newton-Rapshon iterations in the implicit method maintain accuracy of the solution by enforcing equilibrium and recalculating the stiffness matrix at each time step.

On the other hand, explicit analysis is suited for problems that are time dependent including the following situations:

  • High Speed Dynamic or Wave Propagation Events
  • Impacts
  • Crash Simulation
  • Drop Testing

These types of simulation are well characterized by explicit numerical methods. Unlike implicit simulations, iteration is not required. Equilibrium is not enforced through time increments but accuracy is maintained by solving the event over small time steps and recalcuting the stiffness matrix at each step. The computational expense remains low depending on the time domain of the event.

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