Helical Multi-Core Optical Fiber for ATD Collision Strain Sensing
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Solution Overview
Problem
Current collision testing with anthropomorphic test devices (ATDs) faces challenges in accurately monitoring the position and orientation of body parts, especially internal organs and skeletal structures, due to obstructions and the need for precise repositioning for repeatable tests, leading to inconsistent results.
Innovation Solution
A multi-core optical fiber system is integrated into the ATD, featuring grating sensors along its length, which emits and detects light to measure strain, allowing for precise positioning and real-time measurement of stress, strain, and deformation, and can be routed through metal structures to provide comprehensive force analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional strain gauges and high speed cameras are used to monitor ATD body parts, then visual monitoring is possible, but measurement precision is insufficient for internal organs and skeletal structures
Solution Approach 1:
The optical fiber is divided into multiple cores, with each core containing grating sensors at specific locations. This segmentation allows simultaneous measurement of multiple parameters (strain, orientation, position) at different body part locations, improving measurement precision for internal organs and skeletal structures that were previously difficult to detect
Solution Approach 2:
Traditional mechanical strain gauges are replaced with optical fiber grating sensors. The optical fiber system uses light reflection and interference patterns to detect strain and deformation, eliminating the need for mechanical contact sensors that obstructed body parts and provided insufficient measurement precision for internal structures
2Adaptability or versatility
If the ATD is made highly adjustable to allow many different configurations, then adaptability is improved, but it becomes difficult to reposition the ATD into precisely the same position and orientation for subsequent tests
Solution Approach 1:
The optical fiber system provides real-time feedback on the ATD body parts' position and orientation through grating sensor measurements. This feedback enables precise repositioning by comparing current positions with target positions, ensuring repeatable test conditions while maintaining the ATD's adjustability for different test configurations
Solution Approach 2:
This principle does not apply to the patent. The patent uses optical feedback and measurement, not chemical oxidation processes.
3Ease of operation
If cameras are used to realign the ATD for subsequent tests, then positioning is possible, but there is less certainty that the position and orientation is the same, especially for internal body parts
Solution Approach 1:
Visual camera alignment is replaced with optical fiber grating sensor measurements for realignment. The grating sensors provide direct measurement of body part positions and orientations through light reflection patterns, offering superior precision for internal body parts compared to external camera visualization
Solution Approach 2:
The optical fiber system serves multiple functions: it measures strain, position, and orientation simultaneously, and provides data for both real-time monitoring and post-test analysis. This multi-functionality eliminates the need for separate camera systems and ensures consistent precision across all measurement types
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 optical fiber system enhances the biofidelity of ATDs by providing accurate, repeatable, and real-time measurements of structural strains and shapes, improving vehicle restraint evaluations and predicting potential injuries, while minimizing interference and electromagnetic noise.
Implementation Method 1
An emitter is in communication with the optical fiber for emitting a light having a predetermined band of wavelengths through the plurality of cores of the optical fiber that is reflected by the sensors
Implementation Method 2
an interrogator is in communication with the optical fiber for detecting the reflected light from the plurality of grating sensors such that changes to the reflected light indicate a strain on the optical fiber
Implementation Method 3
The plurality of cores are further defined as having at least one location along the respective length where the plurality of cores are helically wound about each other along the fiber axis
Data Source
AI summary
An optical fiber system for a body part of an anthropomorphic test device is disclosed that includes at least one body part and at least one optical fiber that has a plurality of cores in a spaced and helical relationship with one another that extend between ends of the optical fiber for sensing positions of the at least one body part. Each of the cores have a plurality of grating sensors disposed along a length thereof capable of determining a position and orientation of the body part.