Anthropomorphic Dummy Finite Element Model Calibration
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Solution Overview
Problem
The variability in physical anthropomorphic test dummies leads to inconsistent simulation models, affecting the accuracy of crash test results, as different dummies of the same type can produce a range of responses due to inherent variability in mass, material properties, and assembly, which is not adequately accounted for in current finite element models.
Innovation Solution
An automated tool processes variability to create a finite element model of a specific anthropomorphic test dummy, incorporating a database of dummy models, software to read certification test results, an optimizer, and a GUI to automate the optimization process, identifying and minimizing sources of variation in dummy and test setups, and updating the model to improve predictive accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a finite element model uses a single response for a given input, then the model is simple and easy to implement, but it cannot account for dummy variability and produces inaccurate predictions compared to physical dummy ranges
Solution Approach 1:
The patent transforms the static finite element model into a dynamic system that adapts to individual dummy characteristics. The model dynamically adjusts material properties, mass distribution, and structural parameters based on measured data from physical dummies, allowing it to account for variability while maintaining a single unified modeling framework.
Solution Approach 2:
The patent systematically modifies multiple model parameters including material properties (elastic moduli, damping coefficients), geometric dimensions, mass distribution, and joint characteristics to match the specific characteristics of each physical dummy. This parameter customization enables the model to reflect individual dummy variability without requiring multiple separate models.
2Manufacturing precision
If dummy response corridors are widened to allow for manufacturing variation, then manufacturing precision requirements are reduced, but the measurement precision and reliability of test results deteriorate
Solution Approach 1:
The patent implements a feedback mechanism where measured response data from physical dummies is used to calibrate and refine the finite element model. This closed-loop approach allows the model to compensate for manufacturing variations by learning from actual dummy behavior, thereby maintaining measurement precision despite relaxed manufacturing tolerances.
Solution Approach 2:
The patent performs preliminary characterization of each physical dummy through measurement and testing before using it in simulations. By pre-capturing the specific characteristics of each dummy and incorporating them into the model beforehand, the system accounts for manufacturing variations in advance, ensuring accurate predictions without requiring tight manufacturing controls.
3Reliability
If multiple physical dummies are tested to account for variability, then the range of responses is captured, but the time and cost of testing increase significantly
Solution Approach 1:
The patent creates a virtual copy (finite element model) of the physical dummy that can be simulated repeatedly without additional physical testing. Once the model is calibrated using data from a limited number of physical dummies, it can predict responses for various test scenarios, eliminating the need for extensive physical testing while maintaining reliability.
Solution Approach 2:
The patent develops a universal finite element modeling framework that can accommodate multiple dummy types and configurations through parameter adjustment rather than requiring separate models for each case. This multi-functional approach allows the same base model to be adapted to different dummies, reducing the overall testing and modeling time across multiple applications.
Data Source
AI summary
A system and method for designing a crashworthiness system is taught. The system utilizes computer models of anthropomorphic dummies having material properties which change as a function of time.