Improving the validation of finite element models with quantitative full-field strain comparisons

Area of Science:

• Biomechanics
• Experimental Mechanics
• Computational Modeling

Background:

• Traditional finite element (FE) model validation relies on single-point strain gauge measurements, which have limitations in capturing full-field strain distribution and precise positioning.
• The 3D surface topography of bone complicates accurate strain gauge placement, further hindering traditional validation methods.

Purpose of the Study:

• To explore novel methods for quantifying and visualizing strain variations from digital speckle pattern interferometry (DSPI) measurements.
• To compare DSPI-derived strain data with finite element analysis (FEA) results for enhanced model validation.
• To assess the repeatability of DSPI measurements and the accuracy of FEA predictions.

Main Methods:

• Utilized digital speckle pattern interferometry (DSPI) for full-field strain measurement on bone surfaces.
• Developed new quantification and visualization techniques for analyzing strain magnitudes and orientations.
• Compared experimental strain data from DSPI with predictions from two finite element models (FEA).

Main Results:

• DSPI provides a more comprehensive and accurate validation of FE models compared to traditional methods.
• Measurement repeatability and correspondence between measured and predicted strains showed significant variation.
• FE models demonstrated good prediction of strain directions and magnitudes despite simplified material properties.

Conclusions:

• Full-field strain analysis using DSPI reveals discrepancies in FE models related to geometry and material property simplifications.
• Advanced validation techniques are crucial for accurately assessing the performance of biomechanical models.
• DSPI offers significant potential for improving the validation of finite element models in biomechanics.