Crash Test Simulation Interfaces in Vehicle CAD

Crash test simulation interfaces linked with vehicle structural Computer-Aided Design (CAD) models are specialized software bridges that convert static 3D vehicle geometries into dynamic, physics-based finite element analysis (FEA) environments. By seamlessly connecting design models with crash solvers, these interfaces allow automotive engineers to evaluate crashworthiness, occupant safety, and structural integrity under impact conditions digitally, significantly reducing the reliance on costly physical prototypes.

The Connection Between CAD and Crash Solvers

In vehicle development, CAD systems such as CATIA, Siemens NX, and Creo define the exact physical geometry, dimensions, and manufacturing constraints of structural components like chassis rails, A-pillars, and crumple zones. However, CAD models cannot calculate structural deformation, energy absorption, or fracture on their own.

Crash test simulation interfaces bridge this gap by connecting CAD data directly to non-linear explicit dynamic solvers, including LS-DYNA, PAM-CRASH, and RADIOSS. These interfaces translate complex parametric CAD surfaces and solids into discrete finite element meshes (beams, shells, and solid elements) that the physics solvers can interpret.

Core Functions of the Interface

  1. Geometry Discretization and Cleanup: The interface imports CAD topology and automates the defeaturing process—removing minute details like cosmetic fillets or tiny holes that do not contribute to impact dynamics—before generating a high-quality mesh suited for transient dynamic analysis.
  2. Material and Property Assignment: Automotive crash performance depends heavily on non-linear material behavior, strain rate sensitivity, and failure criteria. The interface maps real-world material cards (high-strength steels, aluminum alloys, composite laminates, and plastics) directly onto the corresponding geometric parts.
  3. Assembly Connection Modeling: Modern vehicles rely on thousands of structural joints. The interface models spot welds, laser welds, structural adhesives, bolts, and rivets between disparate CAD parts, ensuring the digital assembly shears and separates realistically under impact loads.
  4. Test Setup and Boundary Conditions: The interface applies regulatory crash scenario parameters directly onto the structural model. This includes defining impact velocities, rigid barriers, deformable offset barriers (such as IIHS or Euro NCAP configurations), gravity, and interaction contacts between colliding surfaces.

Bidirectional Associativity and Design Iteration

A key advantage of integrating crash simulation interfaces with native CAD software is bidirectional associativity. When a crash analysis reveals excessive cabin intrusion or poor energy absorption:

  • Engineers modify structural thicknesses, material grades, or cross-sectional geometries directly within the CAD environment.
  • The interface automatically updates the simulation mesh and boundary conditions to reflect the CAD changes without requiring the entire simulation model to be rebuilt from scratch.
  • This direct feedback loop accelerates design optimization cycles, allowing engineering teams to test dozens of structural iterations in the virtual design phase.

Engineering Benefits

Linking simulation interfaces directly with vehicle structural CAD models ensures that safety standards are embedded early in the vehicle development lifecycle. It eliminates data translation errors between styling, engineering, and testing departments, accelerates time to market, and guarantees that lightweighting initiatives do not compromise vehicle crashworthiness or occupant survival space.