ANSYS Explicit Dynamics Analysis: A Complete Guide for Engineers

When engineering components are exposed to sudden impact, collision, drop, crash, high-speed loading, or severe deformation, conventional static structural analysis may not be sufficient. These situations require a simulation approach capable of capturing rapidly changing loads, contact interactions, large deformation, and nonlinear material behavior.

ANSYS Explicit Dynamics Analysis is a powerful simulation method for studying these short-duration and highly nonlinear events.

In this guide, we explain what ANSYS Explicit Dynamics Analysis is, when engineers should use it, its major applications, typical workflow, and the benefits it can provide during product development.

What Is ANSYS Explicit Dynamics Analysis?

ANSYS Explicit Dynamics is a transient explicit dynamics analysis system available in ANSYS Mechanical. It is designed to simulate nonlinear dynamic behavior of solids, fluids, gases, and their interactions.

Unlike conventional implicit methods, explicit analysis uses very small time increments to calculate the response of a model during a dynamic event. This makes the method particularly suitable for short-duration events involving severe nonlinearities, complex contact, large deformation, and material failure.

Typical applications include:

• Drop test simulation
• Impact analysis
• Crash and collision simulation
• High-speed impact
• Large deformation analysis
• Material failure and fragmentation
• Metal forming
• Penetration mechanics
• Blast and structural interaction
• Complex contact problems

Why Use ANSYS Explicit Dynamics Analysis?

Many real-world engineering events happen within milliseconds or even less. During these events, a component may experience rapidly changing forces, complex contact conditions, plastic deformation, or failure.

Explicit Dynamics is particularly useful when conventional implicit analysis becomes difficult because of strong nonlinearities or convergence problems.

ANSYS identifies applications such as drop testing, high-speed impact, large material deformation, material failure, fragmentation, penetration mechanics, and complex contact as areas where explicit dynamics can be valuable.

ANSYS Explicit Dynamics vs. Implicit Analysis

The main difference is the numerical solution approach.

Implicit analysis generally uses larger time increments and solves equilibrium equations iteratively at each step. It is commonly used for static and many conventional structural problems.

Explicit analysis uses very small time increments and calculates the dynamic response directly. This makes it well suited to highly transient events.

Analysis Type	Typical Applications
Static Structural	Static loads and stresses
Transient Structural	Time-dependent structural response
Modal Analysis	Natural frequencies and mode shapes
Harmonic Analysis	Sinusoidal dynamic loading
Explicit Dynamics	Impact, drop, crash, large deformation and highly nonlinear events

The choice between implicit and explicit methods should depend on the physics and timescale of the problem rather than simply the size of the model.

Key Applications of ANSYS Explicit Dynamics

1. Drop Test Simulation

Products such as electronic devices, tools, equipment, containers, and mechanical assemblies may experience accidental drops during transportation or use.

ANSYS Explicit Dynamics can be used to investigate:

• Impact forces
• Deformation
• Stress distribution
• Plastic deformation
• Contact behavior
• Potential component failure

ANSYS also provides a Drop Test Wizard to help streamline the setup of suitable drop-test simulations.

2. Impact Analysis

Impact events can produce very high forces over extremely short periods.

Examples include:

• Component-to-component impact
• Ballistic or high-speed impact studies
• Tool impact
• Automotive impact
• Protective equipment testing
• Industrial collision scenarios

Explicit Dynamics can capture the transient response and changing contact conditions during the event.

3. Large Deformation Analysis

Some components undergo deformation that is too severe for assumptions commonly used in small-deformation structural analysis.

Examples include:

• Crushing
• Bending
• Buckling-related deformation
• Metal forming
• Plastic deformation
• Structural collapse

Explicit analysis can help engineers study these complex nonlinear responses.

4. Material Failure Analysis

Material behavior can become highly nonlinear when a component experiences extreme loading.

Depending on the selected material model and simulation setup, engineers can investigate phenomena such as:

• Plasticity
• Material failure
• Erosion
• Fragmentation
• Severe deformation

Correct material properties are essential for obtaining meaningful simulation results.

5. Complex Contact Analysis

Contact is one of the major challenges in highly nonlinear simulations.

Explicit Dynamics supports different interaction types, including frictionless, frictional, bonded, and reinforcement interactions. Contact definitions can be used to represent how multiple components interact during a dynamic event.

Typical ANSYS Explicit Dynamics Workflow

A successful ANSYS explicit dynamics analysis requires careful model preparation and setup.

A typical workflow includes the following steps:

Step 1: Prepare the Geometry

Import or create the geometry required for the simulation.

The model should be simplified where appropriate while retaining the important features that influence the physical response.

Step 2: Define Engineering Data

Assign appropriate material properties to the model.

Depending on the application, material characterization may need to include nonlinear properties and behavior relevant to the expected loading conditions.

Step 3: Define Part Behavior

Define how different bodies will behave within the simulation.

The appropriate reference frame and body behavior should be selected based on the physics being modeled.

Step 4: Define Connections and Contacts

Identify how components interact.

This may include:

• Frictional contact
• Frictionless contact
• Bonded contact
• Self-contact
• Other body interactions

Accurate contact definition is particularly important for impact and collision simulations.

Step 5: Create the Mesh

Generate a suitable finite element mesh.

Mesh quality and element size can significantly influence simulation accuracy and computational cost.

For explicit simulations, efficient mesh design is especially important because the stable timestep can be influenced by element characteristics.

Step 6: Apply Loads and Boundary Conditions

Define the conditions representing the real-world event.

Examples include:

• Initial velocity
• Gravity
• Impact velocity
• Forces
• Constraints
• Initial conditions
• Other dynamic loading conditions

Step 7: Define Analysis Settings

Set the required simulation time, timestep controls, solver settings, damping, erosion, and output controls according to the engineering problem.

Step 8: Solve the Simulation

Run the explicit dynamics solver and monitor the solution.

For complex simulations, engineers should review the solution behavior and numerical stability rather than relying only on the final result.

Step 9: Postprocess the Results

After solving, review the important engineering outputs.

Typical results may include:

• Total deformation
• Equivalent stress
• Plastic strain
• Contact forces
• Velocity
• Acceleration
• Energy
• Reaction forces
• Material failure or erosion indicators

ANSYS provides result trackers and postprocessing tools for reviewing the dynamic response.

Important Considerations for Accurate Explicit Dynamics Simulation

An accurate simulation depends on more than simply selecting the Explicit Dynamics analysis system.

Material Properties

Material data should represent the actual material and loading conditions as closely as possible.

For nonlinear and failure simulations, appropriate material models and experimental data can be particularly important.

Mesh Quality

A poor mesh can lead to inaccurate or inefficient simulations.

Mesh refinement should focus on areas where high gradients, contact, deformation, or failure are expected.

Contact Definition

Incorrect contact definitions can significantly affect impact and deformation results.

Engineers should carefully evaluate:

• Contact type
• Friction
• Contact detection
• Self-contact
• Penetration
• Contact stiffness and related settings

Time Step

Explicit methods generally use very small timesteps. Simulation efficiency can therefore depend strongly on the model’s smallest relevant elements and solver settings.

Boundary Conditions

Incorrect constraints can produce unrealistic deformation or forces.

Boundary conditions should represent the actual physical test or operating condition as closely as possible.

ANSYS Explicit Dynamics for Product Development

Using simulation during product development can help engineers identify potential design problems before physical prototypes are manufactured.

For example, an engineering team developing a protective enclosure could use explicit dynamics to study a drop event.

The simulation could help answer questions such as:

• Where does maximum deformation occur?
• Which component experiences the highest stress?
• Does the enclosure absorb the impact effectively?
• Does the internal component remain protected?
• Which design requires reinforcement?
• How does changing material thickness affect the response?

This approach can support design optimization and reduce dependence on repeated physical prototypes.

When Should You Consider Explicit Dynamics?

Explicit Dynamics may be appropriate when your engineering problem involves:

• Very short-duration dynamic events
• High-speed impact
• Large deformation
• Severe nonlinear behavior
• Complex contact
• Material failure
• Crushing or collapse
• Drop testing
• Collision or crash events
• Problems where implicit convergence becomes difficult

The correct analysis method should always be selected based on the physics, loading conditions, timescale, material behavior, and objectives of the simulation.

ANSYS Explicit Dynamics and LS-DYNA

ANSYS provides several technologies for explicit simulation. Within the ANSYS ecosystem, LS-DYNA can also be used for advanced explicit analysis.

The appropriate solver depends on the complexity of the engineering problem, required physics, available material models, and the analyst’s requirements.

For highly specialized applications, experienced simulation engineers can help determine the most suitable approach.

Benefits of ANSYS Explicit Dynamics Analysis

A properly configured simulation can provide valuable engineering insights before physical testing.

Key benefits include:

• Better understanding of impact behavior
• Evaluation of large deformation
• Investigation of nonlinear material response
• Analysis of complex contact
• Identification of potential failure locations
• Support for product design optimization
• Reduced dependency on repeated prototypes
• Improved understanding of dynamic loading

Conclusion

ANSYS Explicit Dynamics Analysis is an important simulation approach for engineers working with impact, drop tests, crash events, large deformation, complex contact, and other highly nonlinear dynamic problems.

A reliable simulation requires appropriate geometry, material data, mesh quality, contact definitions, boundary conditions, solver settings, and result interpretation.

At SolidTrust, engineering simulation can help organizations understand complex physical behavior and make better-informed design decisions.

If you are working on an impact, drop test, crash, large deformation, material failure, or other nonlinear dynamic engineering problem, contact SolidTrust to discuss your simulation requirements.

Need ANSYS simulation support? Contact SolidTrust today to discuss your engineering analysis requirements.