Project Background

Stala Framing, a leading manufacturer of high-performance exterior doors partnered with PEC to evaluate and enhance a steel-reinforced paired door system designed for high-wind, hurricane-, and tornado-prone regions. The objective was to obtain ICC 500 certification for wind-borne debris impact requirements.

Prior to PEC’s engagement, initial full-scale impact testing demonstrated that the original door design failed to satisfy the ICC 500 performance requirements. PEC was engaged to: (1) develop a high-fidelity finite element (FE) model to simulate the behavior of the original door design; (2) leverage the FE model to identify door failure modes and corresponding critical structural weaknesses under wind-borne debris impact; and (3) engineer an optimized door design capable of achieving the ICC 500 impact rating. Subsequent full-scale impact testing confirmed that the revised door design successfully resisted a 15-lb 2×4 lumber projectile traveling at 100-mph, thereby achieving ICC 500 certification.

Numerical Modeling and Simulation

PEC developed a high-fidelity FE model of the complete door assembly, including the door panels, frame, hinges, latching hardware, and anchorage into an 8-in. thick insulated concrete form (ICF) wall. Advanced material models were employed to capture nonlinear behavior, including plastic deformation, transient strain-rate effects, strain localization, and post-peak behavior up to rupture. Boundary conditions replicated the test configuration, including frame constraints and installation details. Views of the FE model are shown in Figure 1.

Figure 1: High-fidelity FE model of the complete door assembly.

To simulate the wind-borne debris impact event, nonlinear dynamic analyses were performed with the timber projectile modeled using solid (brick) elements and assigned appropriate geometry, density, and impact velocity in accordance with ICC 500 requirements. Contact interactions between the projectile and the door surface were carefully defined to capture localized stress/strain effects to ensure accurate energy transfer during impact. Animation of impact event simulations performed in LS-DYNA are shown in Figure 2.

Figure 2: Animation of impact event simulations.

FE Model Validation

The FE models were validated against the initial full-scale impact test data to ensure confidence in numerical predictions. Permanent door deformation was selected as the key performance metric to compare the simulation results with the test measurements. Correlation studies demonstrated strong agreement, with predicted permanent deformations within 10% of experimental values and accurate identification of governing failure modes. Impact testing further confirmed that the simulated deformation patterns and phenomenology closely matched experimental test data. Figure 3 illustrates the post-impact specimen condition observed in that predicted by FE simulation and were resembling the proprietary physical test data.

(a) Front Face

(b) Front Face – Close-up View

(c) Rear Face

Figure 3: Post-impact specimen conditions from FE simulation.

Design Optimization

A series of parametric studies were conducted using the validated numerical model to optimize the door assembly for ICC 500-compliant impact resistance. Design variables included panel material type, internal reinforcement layout and size, and frame bite. Simulation results (Figure 4) demonstrated that modest increases in reinforcement layout, size and frame bite (Figure 5) significantly reduced door permanent deformation. Alternative material selection for the door assembly improved energy absorption while maintaining manufacturability. By addressing critical load paths identified through simulation, the optimized design achieved improved impact performance with minimal changes.

Figure 4: FE simulation confirming ICC 500-compliant impact resistance of optimized door design.

Figure 5: Frame bite optimized design resulting in improved impact resistance.

ICC 500 Compliance

The optimized door design was subsequently tested in accordance with the ICC 500 requirements and successfully achieved the desired wind-borne debris impact rating. Our predictive simulations played a central role in this outcome, accurately forecasting impact response, deformation patterns, and governing failure modes prior to physical testing. This case demonstrates the value of numerical analysis tools in product development when applied appropriately by experienced consulting teams. Our approach reduced development risk, minimized the number of test iterations, and enabled first-pass certification, providing a reliable and cost-effective pathway to compliance.

Summary

This project showcases our ability to combine advanced simulation technique with engineering insight, enabling clients to: (1) identify and remediate structural weaknesses early, (2) reduce costly physical testing, and (3) achieve compliance with rigorous standards such as ICC 500.

Call to Action

If you manufacture doors, windows, or other building envelope components intended for high-wind or storm-resistant applications and need expert modeling, optimization, and certification support, contact us today. We can help you design safer, stronger, and code-compliant products ready for real world challenges.

Key Skills and Services

• High-fidelity 3D FE modeling and nonlinear dynamic impact simulation
• Calibration and validation of numerical models against experimental results
• Predictive structural analysis to identify weak points under extreme load conditions
• Design optimization to meet stringent safety standards
• Support for product certification

For more information regarding Stala Framing, contact Brandy Littrell.

For more information about high-fidelity analysis of shock and impact loaded components, contact Eric Sammarco or Michalis Hadjioannou.