Translating Professional Football Helmet Tests to Full Body Finite Element (FE) Simulations: A Reproducible Field-to-Simulation Workflow

Summary

This article presents a reproducible workflow that converts real national football league (NFL) plays into solver-ready full-body finite element simulations. Single-view video reconstructs 6-DoF skull-CG kinematics, applies event-specific helmet hardware, and enforces quality-control gates for stability, energy balance, and driver fidelity to support cross-lab reproducibility without injury claims.

Abstract

This article presents a reproducible field-to-simulation workflow that translates real football plays into solver-ready boundary conditions for a full-body finite-element human model. Single-view video reconstructs six-degree-of-freedom kinematics at the skull CG; these signals are applied to a helmet–head–body assembly that preserves event-specific hardware. The protocol codifies quality-control gates before interpretation: (I) helmet readiness (mesh integrity, contact stability), (ii) mass and center-of-gravity agreement between the physical configuration and its FE surrogate, (iii) energy balance with bounded spurious energies, (iv) driver-fidelity metrics comparing target versus solver-applied motion (RMSE, peak magnitudes, time-to-peak), and (v) versioned inputs for auditability. A demonstration replay verifies numerical stability and driver fidelity, and reports tissue-level response and diagnostic damage metrics as process outputs without making injury claims. For studies requiring internal response, the framework supports physics-based constitutive models (Internal State Variable formulations) and treats them as process diagnostics unless separately validated. By separating readiness checks from injury interpretation, the method provides a practical foundation to standardize helmet integration, enable cross-laboratory reproducibility for event scenarios, and inform safer design and policy. Although developed for sport, the workflow generalizes to transportation and defense settings where ethical constraints prevent human experimentation.

Introduction

The goal of this end-to-end reconstruction method is to represent real-world player impacts by converting field evidence (video and/or wearables) into a simulation-ready human–helmet assembly. The protocol provides procedural steps and quality-control gates to integrate a legacy football helmet with a whole-body finite-element (FE) human model and to enable event-specific simulations that can later be analyzed for safety insights. Head impacts in contact sports highlight a key limitation of controlled league laboratory programs^1,2,3,4. NOCSA....

Protocol

1. Helmet preparation (FE surrogate ready for coupling)

1. Identify configuration.
2. Open LS-PrePost and Import selected the helmet FE surrogate with faceguard and hardware matching the event configuration.
   1. Record padding set/size and chinstrap routing; Note solver/model versions: LS-PrePost³⁴ and Velodyne¹⁶.
3. Sanity-check mass properties.
   1. In LS-PrePost, open measurement and set the dropdown item menu to mass. Use 3-pt radius to define the h....

Results

The material and reconstruction checks met predefined acceptance criteria. Figures 1–2 show that the brain tissue Internal State Variable (ISV) model exhibits similar behavior in compression and simple shear at matched rates; the ISV model with damage reproduces low-rate compression and the 30–60 s⁻¹ strain rates (Figure 3), with SPHB specimen trends captured in FE (Figure 4). The helmet FE assembly and inputs, fully specified in

Discussion

This work couples single-view video–based 6-DOF reconstruction with full-body finite element (FE) replay to provide a process-only path from a real play to a numerically stable, configuration-faithful simulation. Unlike traditional laboratory tests (twin-wire drop standards; league laboratory linear-impactor tests), which deliberately idealize loading, the present workflow preserves event-specific conditions, helmet model and fit, player-to-player impact kinematics, and converts field footage into solver-ready boun.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Video digitization software	Kinovea Project	N/A	Kinovea v2023.1.2 used to click helmet landmarks and export kinovea_clicks.csv (frame, landmark, u, v).
Reconstruction language/runtime	Python Software Foundation	N/A	Python v3.13.7 used to run the reconstruction script.
Computer vision library	OpenCV (opencv-python)	N/A	Required for cv2.solvePnPGeneric (UPnP) and Rodrigues rotation conversion.
Numerical computing libraries	NumPy; pandas	N/A	Used for vector/matrix ops, CSV I/O, and kinematic post-processing.
Reconstruction script	Custom (Supplementary)	reconstruct_6dof_upnp.py	Zoom-aware single-view UPnP pose per frame; outputs poses_per_frame.csv, kinematics.csv, initial_conditions_t0.csv, qc_summary.txt, qc_per_frame.csv.
Reconstruction configuration	Custom (Supplementary)	Config.json	Inputs: fps=59.94; principal_point=[640,360]; cutoffs (linear 15 Hz, angular 40 Hz, focal 5 Hz); helmet_to_com=[-0.1,0.4,0.0] m.
3D landmark template	Custom (Supplementary)	helmet_landmarks.csv	3D helmet landmark coordinates (m) in helmet coordinate system: (landmark, X, Y, Z).
Digitized landmark clicks	Custom (Supplementary)	kinovea_clicks.csv	Per-frame 2D clicks exported from Kinovea: (frame, landmark, u, v).
FE pre/post-processor	Livermore Software Technology Corporation (LSTC)	N/A	LS-PrePost v4.12 used to inspect meshes, mass properties, contacts, and apply/verify axes points P/Q if needed.
Veloldyne Explicit FE solver	Corvid Technologies	N/A	Velodyne explicit solver v24p11; used for replay simulations (hourglass, bulk viscosity, contact, mass scaling controls).
Full-body human FE model	Corvid Technologies	CAVEMAN v25p5 (licensed)	Finite-element human body model used for helmet coupling and whole-body replay; licensing may restrict redistribution.
2016 Riddell Revolution Speed Classic Helmet	Purdue University (Sean Bucherl); BioCore (source model)	BioCore RRSC v2 (Sep 2019); adapted Velodyne	2016 Riddell Revolution Speed Classic (RRSC) helmet FE surrogate used for coupling. Model provenance: based on the BioCore RRSC LS-DYNA model (v2 Sep 2019) and provided/adapted for this work by Sean Bucherl (Purdue University). Redistribution may be license-restricted; provide access upon reasonable request under the applicable agreement.