In static analysis there is no effect of mass (inertia) or damping. Nodal forces associated with mass/inertia and damping are included in the dynamic analysis. The static analysis is performed using an implicit solver in LS-DYNA. Dynamic analysis can be performed via the explicit solver or the implicit solver. In implicit nonlinear analysis, the solution of each step requires a series of trial solutions (iterations) to establish equilibrium within a certain tolerance. In explicit analysis, no iteration is required since nodal accelerations are solved directly. The time step in explicit analysis must be less than the Courant time step (the time it takes for a sound wave to travel through an element). Implicit transient analysis has no inherent limitations on the size of the time step. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an Original EssayAs such, implicit time steps are generally several orders of magnitude larger than explicit time steps. Implicit analysis requires a numerical solver to invert the stiffness matrix one or even more times during a load/time phase. This matrix inversion is an expensive operation, especially for large models. Explicit does not require this step. Explicit analysis handles nonlinearities with relative ease compared to implicit analysis. This would include the treatment of contact and material nonlinearities. In explicit dynamic analysis, nodal accelerations are solved directly (not iteratively) as the inverse of the diagonal mass matrix multiplied by the net nodal force vector where the net nodal force includes contributions from external sources (body forces, applied pressure, contact, etc.), element stress, damping, apparent viscosity and hourglass control. Once the accelerations at time n are known, the velocities are calculated at time n+1/2 and the displacements at time n+1. Tension comes from displacements. From tension comes stress and the cycle repeats (LS-Dyna Support.com, n.d.). (Hua Song et.al), (Jian Yang et.al) examined the differences between applying FEA methods via implicit-explicit and explicit-explicit techniques. It was reported that the Explicit-Explicit method showed the same level of accuracy as the common Implicit-Explicit method. Please note: this is just an example. Get a custom paper from our expert writers now. Get a Custom Essay The Explicit-Explicit method however had a faster solver that worked better than that of the Implicit-Explicit FEA method. Other researchers tried analytical methods (Mehmet Ali Arslan, 2011) and documented that analytical methods describing the physics of the Rail-Wheel contact phenomenon were only defined for some types of simple contact geometries. For complex geometries it was argued that analytical models using closed formulations remained elusive. (Mehmet Ali Arslan, 2011) performed a static FEA analysis using Ansys on a section of a track and on the profile of a wheel to evaluate the stresses.