MSC Nastran vs MSC Dytran: Implicit vs Explicit FEA
Two solvers, two very different classes of problem. Here's how to know which one your analysis needs.
MSC Nastran and MSC Dytran are both finite element analysis (FEA) solvers from the same Cadence MSC Software portfolio, and both are distributed in the Nordics by SimEvolution. They are not competing products — they solve different classes of engineering problem, and many organisations run both, often on the same structure at different stages of its analysis. This guide explains the difference in plain terms, so you can pick the right tool the first time.
What is the core difference?
The difference comes down to time integration method . MSC Nastran is primarily an implicit solver: it is built for static loads, low-to-moderate frequency dynamics, buckling, thermal and nonlinear analysis where the structure's response can be solved as a system of equations over relatively large time or frequency steps. MSC Dytran is an explicit solver: it steps through time in extremely small increments — typically fractions of a microsecond — which is the only stable way to capture events where loads, stresses and deformation change violently within milliseconds.
When should you use MSC Nastran?
Use MSC Nastran when you need certified, high-confidence analysis of how a structure behaves under normal-to-moderate operating conditions. Typical Nastran analyses include:
- Linear static strength and stiffness checks
- Normal modes and vibration (modal) analysis
- Frequency response and random vibration
- Buckling analysis
- Heat transfer and thermal-structural coupling
- Nonlinear static and dynamic analysis
- Rotor dynamics and aeroelasticity
- Structural optimisation
MSC Nastran is the only FEA solver certified by the FAA for aircraft structural analysis, and it remains the industry benchmark wherever certified, auditable structural results are required.
When should you use MSC Dytran?
Use MSC Dytran when the event you need to analyse unfolds in milliseconds and involves extreme deformation, material failure or fluid-structure interaction — the class of problem implicit solvers are not built to capture reliably. Typical Dytran applications include:
- Bird strike on aircraft structures and engine fan blades
- Blast and explosion loading
- Underwater shock
- Ballistic penetration and armour analysis
- Crashworthiness and occupant safety
- Airbag deployment and other fast fluid-structure events
MSC Dytran supports Lagrangian (structural), Eulerian (fluid/gas) and ALE formulations, plus Smooth Particle Hydrodynamics (SPH) for extreme fragmentation, with native fluid-structure interaction built in — no separate co-simulation setup required. It is FAA-accepted for bird strike and hail impact certification analysis.
Side-by-side comparison
| MSC Nastran | MSC Dytran | |
| Solver type | Implicit | Explicit |
| Typical time step | Seconds to whole load steps | 0.05–0.5 µs |
| Best suited to | Static, modal, buckling, thermal, moderate dynamics | Impact, blast, crash, penetration |
| Event duration | Steady-state or slow transients | Milliseconds |
| Certification | FAA-certified for aircraft structures | FAA-accepted for bird strike / hail impact |
| Input format | MSC Nastran bulk data | Same bulk data format as Nastran |
Do I need both?
Often, yes — and this is where the two solvers complement each other directly. Because MSC Dytran uses the same input deck format as MSC Nastran, teams commonly build a single structural model, run the certified static/modal checks in Nastran, and reuse the same geometry and material data in Dytran for the extreme-event analysis. Loads extracted from a Dytran impact event can also be handed back into Nastran for downstream fatigue or residual-strength assessment.
How SimEvolution can help
SimEvolution is the certified Nordic reseller for MSC Nastran and MSC Dytran. If you are not sure which solver — or which licence configuration — fits your project, contact us for a technical conversation rather than guessing from a feature list.
Frequently Asked Questions
MSC Nastran includes nonlinear dynamic analysis capability, but for extreme, short-duration events with large deformation, material failure or fragmentation, MSC Dytran's explicit method is the appropriate and validated tool.
No — MSC Dytran uses the same input deck format as MSC Nastran, so teams already using Nastran can move to explicit analysis without a new pre-processor or material library.
Aerospace (bird strike, hail impact), defence (blast, ballistic penetration), automotive (crashworthiness) and marine/offshore (underwater shock) are the most common users of MSC Dytran.