Facemask Stiffness Measurement via Controlled Point Load
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Solution Overview
Problem
Current methods for evaluating football facemask performance, such as the NOCSAE twin-wire drop apparatus, are destructive and lack sensitivity, failing to differentiate between facemask designs effectively, and are confounded by the presence of the helmet system, necessitating a non-destructive and more sensitive method to assess facemask structural stiffness independently.
Innovation Solution
A system and method involving a force generator with a contact plate to apply a controlled point load to the facemask, allowing for measurement of structural stiffness with two lateral and one rotational degree of freedom, enabling non-destructive testing and differentiation across facemask styles and materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the NOCSAE twin-wire drop apparatus is used to evaluate facemask performance, then impact severity can be measured, but the testing method causes permanent damage to the facemask and cannot differentiate facemask designs effectively
Solution Approach 1:
The testing system segments the facemask evaluation from the complete helmet system, isolating the facemask as a separate testable component. This allows direct measurement of facemask structural stiffness without the confounding factors of helmet padding, shell, and other components that prevent accurate facemask performance differentiation in traditional drop tests.
Solution Approach 2:
Instead of applying impact forces to evaluate facemask performance (destructive approach), the invention inverts the approach by applying controlled static or quasi-static loads to measure structural stiffness. This reversal allows non-destructive evaluation while maintaining sensitivity to facemask design differences.
2Measurement precision
If the NOCSAE twin-wire drop apparatus is used, then impact evaluation can be performed, but the results are confounded by helmet system components and cannot isolate facemask performance
Solution Approach 1:
The invention extracts the facemask from the complete helmet system for independent testing. By removing the facemask from its integrated helmet context and testing it as a standalone component mounted to a rigid support structure, the system eliminates confounding factors from helmet padding, shell, and other components that interfere with accurate facemask performance measurement.
Solution Approach 2:
The testing system segments the facemask evaluation from the complete helmet system, isolating the facemask as a separate testable component. This allows direct measurement of facemask structural stiffness without the confounding factors of helmet padding, shell, and other components that prevent accurate facemask performance differentiation in traditional drop tests.
3Measurement precision
If destructive testing methods are used to evaluate facemasks, then impact performance can be assessed, but the facemask cannot be tested at various points in its life cycle
Solution Approach 1:
Instead of applying impact forces to evaluate facemask performance (destructive approach), the invention inverts the approach by applying controlled static or quasi-static loads to measure structural stiffness. This reversal allows non-destructive evaluation while maintaining sensitivity to facemask design differences, enabling repeated testing throughout the facemask lifecycle.
Solution Approach 2:
The facemask serves its own testing needs through the non-destructive stiffness measurement process. The same facemask can be repeatedly tested at various points in its lifecycle (new, in-service, reconditioned) without degradation from testing itself, allowing the object to be continuously evaluated rather than requiring replacement after single-use destructive testing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method provides repeatable, non-destructive measurements of facemask stiffness, capable of differentiating between various designs and materials, improving upon existing evaluation paradigms by avoiding permanent damage and helmet system confounding factors.
Implementation Method 1
A force generator provides a controlled input deflection that is applied as a point load to the facemask in various locations. The load required to reach the applied deflection of the facemask is measured and charted
Data Source
AI summary
A force generator applying a force load against a facemask. A first load cell carrying a first portion of the facemask at an attachment point of the facemask where the facemask is attachable to a helmet. A second load cell carrying a second portion of the facemask at another attachment point of the facemask where the facemask is attachable to a helmet. A first attachment platform carrying the first load cell, wherein the first attachment platform is laterally movable in at least two degrees of freedom. A second attachment platform carrying the second load cell, wherein the second attachment platform is laterally movable in at least two degrees of freedom. The force generator directs the contact plate against the facemask to cause a horizontal deformation of the facemask and a lateral movement of the attachment platforms to allow for repeatable force load testing on a single facemask.