Validation Notes on PC-CRASH Simplified Momentum

General Questions related to the Momentum Based Analysis programs
#pc-crash #virtualcrash #crash
MSI
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Validation Notes on PC-CRASH Simplified Momentum

Post by MSI »

Feb 2022: The following was split from the topic More Discussion on issues with PC-CRASH type simplified momentum solutions from August 2020 to Dec 2020.
  • We are in the process of updating a discussion of What is Validation and so wanted this section with the reporting on validation results for pc-crash to be separate.
Below is a figure which demonstrates the arbitrary "Impact Point", Coefficient of Restitution" and "Contact Point Angle and MU"
  • First for the Validation Optimizations Paper 2001-01-0507
    • the input are listed and were set to ACHIEVE CORRELATION WITH KNOWN TEST RESULTS
      • Therefore they are Optimized as part of the Optimization "Validation".
    • What if you DO NOT KNOW the results you want/need?
      • how to you objectively set these input variables to approximate the 50-150 millisecond collision by an instantaneous point and angle?
      On their BEST validation (Table 8 from SAE 2001-01-0507..they STILL have high error percentages?
      pc-crash validation summary.jpg
      pc-crash validation summary.jpg (86.36 KiB) Viewed 4579 times
  • The second lists to right are from paper 2012-01-0604
    • Table 1 and the Table 2 list of variables which show they DO NOT include any test or variation on the sensitivity of the arbitrary and subjective "Impact Point",
      • They also do not list the vehicle fixed location on each vehicle for the 'point of momentum exchange'...it is a Space fixed listing
      • SO how do you determine how it compares to the area of the damage when listed as a space fixed point?
        Obviously if they provided the input and/or graphics of the impact (larger than the small pics in the report (see below)
    • Coefficient of Restitution"(it is listed but minor/no effect? (see figure below)) and "Contact Point Angle and MU (MU listed but minor/no effect? see figure below))".
    A step-by-step protocol needs to be established and published by pc-crash to allow for an objective and scientific determination of these highly subjective inputs.
Comparison of variables tested Ver2.jpg
Comparison of variables tested Ver2.jpg (436.42 KiB) Viewed 5732 times
The following is a comparson of the Global Variables tested in 2002-01-0604 vs those used in 2001-01-0507:
Comparison Global variables tested.jpg
Comparison Global variables tested.jpg (389.8 KiB) Viewed 5732 times
The following is a schematic of the pc-crash COLLISION MODEL with Friction Cone, Contact Plane & Crash Impact Vector displayed
PC-CRASH COLLISION MODEL.jpg
PC-CRASH COLLISION MODEL.jpg (94.29 KiB) Viewed 5735 times
The following is a comparison of Impact Friction and Restitution for Various Pc-Crash References
And note for 2012 reference little or no variation indicated
Comparison IMpact friction and EPS from various references for Validation tests.jpg
Comparison IMpact friction and EPS from various references for Validation tests.jpg (299.58 KiB) Viewed 5724 times
The following is from the 2012 refrence
restitution and impact friction variations.jpg
restitution and impact friction variations.jpg (64.93 KiB) Viewed 5724 times
Click here to return to the previous thread (from which this was separated)
ricsac 1-12 pc-crash validation s.jpg
ricsac 1-12 pc-crash validation s.jpg (288.47 KiB) Viewed 5113 times
Pc-crash Jari validation run displays.png
Pc-crash Jari validation run displays.png (549.84 KiB) Viewed 5113 times

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