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Cumulative Strain Damage Measure (CSDM)
Overview
The Cumulative Strain Damage Measure (CSDM) was developed by Takhounts et al, in 2003 to measure the strain experienced by the brain during an impact [1]. It captures the percent of the brain exceeding a specified maximum principal strain value. The most commonly used strain threshold for this metric is 0.25, which was originally correlated to diffuse axonal injury.
The required file can be found in the “instrumentation” folder where Metriks was installed, e.g.:
C:\Program Files (x86)\Metriks\instrumentation\M50-O\v6.0\GHBMC_M50-O_v6.0_CSDM.k
| Panel Descriptions | |
|---|---|
| 3D Visualization of Brain Elements included in CSDM Calculation | Summary Table with Risk of AIS 4+ Injury (DAI) and CSDM value |
| Summary Table of Brain Volume Injured and CSDM value | |
| Injury Risk Curves for CSDM [1] | |
Calculation Methods
1. A data structure containing the initial volume of each solid element of the brain (for each HBM) is stored in Metriks.
2. Calculate maximum principal strain histories for all brain elements throughout the simulation.
3. For each time point, identify all elements exceeding the strain threshold (can be modified in Calculation Settings; default=0.25).
4. Sum the volumes of elements exceeding the strain threshold at each time point.
5. Calculate instantaneous CSDM value at each time step as the volume of elements exceeding the strain threshold divided by the total volume of solid brain elements.
6. Metriks reports CSDM as the peak instantaneous CSDM value throughout the entirety of the simulation.
References
[1] Takhounts E.G, Eppinger R.H., Campbell J.Q., Tannou R.E., Power E.D., Shook L.S. (2003) On the Development of the SIMon Finite Element Head Model. Stapp Car Crash J.(47) pp. 107-133.