Energy – CRASH3 (CRUSH5 – DeltaV from Damage)

 

Overview:  Uses enhanced Crash3 Damage Analysis algorithms to compute collision data including Equivalent Barrier Speeds and the DeltaVs (change of velocities) for the collision.  If supplied with the collision angles (A2, A3, and A4) it will also compute the Impact and Post-Impact velocities (V1, V2, V3, and V4) for the collision. 

 

Entry into Module:

 

This module of the program is normally entered by clicking on the REC-TEC block in the upper left of the REC-TEC Window causing the drop-down menu to appear.  Place the cursor on the Energy block and click on CRASH3 (CRUSH5 – Delta V from Damage) on the sub-menu to initiate this module.

 

Under certain circumstances, the user may choose to use the Files block instead of the drop-down menu approach.  Selecting any file with a .CRS extension in the Dialog box accessed from either the Open Single File or Open Multiple Files block opens this module.

 

Selecting AutoLoad [ON] from either the Setup Menu or the AutoLoad Icon on the upper right side (third line) of the REC-TEC Window automatically loads the two-vehicle scenario that was on the screen when the module was closed, either individually, or when the program was closed.  With AutoLoad [OFF] on the main REC-TEC Window, modules will start without loading a file.  Use AutoLoad [OFF] and manually load the file if only one vehicle is involved.

 

Data Entry:

 

This module contains the following data entry blocks:

 

Crush5

 

·             Centroid:

o  RT – REC-TEC Equations for Centroid

o  PE – Parkka Equations for Centroid

o  ME – Mitchell Equations for Centroid

 

·             Vehicle:

o  Vehicle 1

o  Vehicle 2 (If second vehicle)

 

·             Description – Vehicle (N) Description (Optional)

 

·             Category

o  Default – Sets defaults for Entered Vehicle Category

o  Textbox – Entry of Category for Vehicle (Zero for no Category)

 

·             Weight – Weight of Vehicle

·             Damage Width – Width of Damage (L)

·             Damage Offset – CG is reference point.  If damage is forward or right, use a positive value; if rearward or left, use a negative value.

·             PDOF – 0 to +/- 180 degrees  0 = Front, 180 = Rear, -90 = Left, +90 = Right

·             Stiffness A – Stiffness Coefficient A

·             Stiffness B – Stiffness Coefficient B

·             Stiffness G – Computed

 

Surface (Damage)

·             Front

·             Rear

·             Right

·             Left

                 

·             Yaw Radius of Gyration – Blank to have program compute

·             Wheelbase – Front axle to Rear axle

·             CG – Front Axle – Distance from CG to Front Axle

·             CG – Front – Distance from CG to Front

·             Vehicle Length – Length of Vehicle

·             Vehicle Width – Width of Vehicle

 

Optional Inputs (COLM) – A1 assumed to be 0 degrees (LHCS/H)

 

Optional Data  (for Scale Diagram in Graphics only - does not enter computations)

·             Front Track

·             Rear Track

·             Tire Radius (F)

·             Tire Radius (R)

·             Tire Width (F)

·             Tire Width (R)

 

Crush Measurements (2 minimum / 20 maximum)

·             C01 to C20 - Use as required

·             L01 to L20 – Cumulative Distance from L01.  L01 is always Zero (0).

·             % (19) – Weight for Segment as percent (1 to 100) defined by adjacent “C” measurements

 

Non Linear Crush5 Functions (Check to Enable)

 

·             Percent of “C” Measurement

o  Zone (1 to 3) – Length of “C” enables defining three separate Zones

o  Percent  – Weight for Zone as percent (1 to 100) defined by length of “C” measurements

 

·             Inches of “C” Measurement

o  Zone (1 to 3) – Length of “C” enables defining three separate Zones

o  Percent  – Weight for Zone as percent (1 to 100) defined by length of “C” measurements

 

Test Collision Data (Used to compute A, B & G Stiffness Coefficients)

 

·             Crush Energy Equivalent Speed – Exemplar Vehicle in Test Crash

·             Maximum CEES without Permanent Damage

·             Average Crush – Enter 0 (Zero) to Compute

o  Number of “C” Measurements

o  Length of (Each) “C” Measurement

·             Test Vehicle Weight – Exemplar Vehicle in Test Crash

·             Test Vehicle Damage Width – Exemplar Vehicle in Test Crash

 

Collision Force Error

 

·             Two light yellow Command Buttons with the Collision Force for Vehicle 1 and Vehicle 2 appear in the Crush5 Analysis Output frame if there is an imbalance of the Collision Forces between the vehicles.  Click on the Collision Force to be changed to engage a frame that shows the information required to balance the Collision Forces of the vehicles

·             A light blue Command Button (=) allows the user to average the (Peak) Collision forces of the two vehicles and use this average Force to compute new A and B Stiffness values for the vehicles balancing the Collision forces..

 

Output:

 

Central Collision 

 

·             Crush Energy – Energy required for Damage

·             Equivalent Barrier Speed – Speed of Central Collision with Barrier required to cause damage.

·             Mass – Mass of vehicle

·             Yaw Raduis of Gyration – Computed or Supplied

·             Inertia Moment (Mass * Radius of Gyration) – Resistance to Rotation

·             CoD (X) – Depth – Depth measurement - Similar to “C” measurement

·             CoD (Y) – Width – Width measurement - Similar to “L” measurement

·             Damage Area – Computed area of Damage

·             Moment Arm (Length) – Lever Arm through which Force acts on CG

·             Gamma (Y) Value – Equivalent Mass

·             Linear Impulse – Equal Magnitude and Opposite Direction

·             Collision Force – Peak (See Collision Force Error above)

·             Energy - Dissipated – As Damage (Individual Vehicle)

·             Energy - Dissipated (Total) – As Damage for both vehicles combined

·             Energy - Maximum – Maximum Available for Damage, Rotation and Motion (Translational)

·             Delta T – Linear Impulse / Average Collision Force

·             G (Acceleration Factor) – Computed

·             Speed- Closure – Closing Speed of Vehicles

·             Speed – Equivalent Barrier – Reduced Mass (non-Central) Barrier Speed

 

Delta V

 

·             Delta V (Angular) – Angular Rotation – A negative number indicates a Counter-Clockwise rotation

·             Delta V (Angular) – Angular Rotation – A negative number indicates a Counter-Clockwise rotation

 

·             Delta V (Longitudinal) – Longitudinal Vector Change (Speed and/or Direction)

·             Delta V (Lateral) – Lateral Vector Change (Speed and/or Direction)

 

·             Delta V (Total) – Total Vector Change (Speed and/or Direction)

 

Impact and Post-Impact Speeds

 

Text files for CAD conversion to .dxf files:

 

·             Vehicle1.ASC and Vehicle2.ASC – These files are text files that most CAD programs can import and convert to .dxf files.  This will allow the user to export files with the damage profiles and vector data as they appear in this module for direct conversion to .dxf files.  If vehicle data from AutoStats or Autostats Lite is imported into CRUSH, those vehicles, drawn to scale with scale damage, can be exported and converted.  These files are created when the Graphics are displayed.

 

Options: 

 

Several Command Buttons appear in a frame located at the lower right corner of the module Window.  The Command Buttons allow the user to engage options including the option to Open and Save the data (for Vehicle 1 and Vehicle 2) required to generate the scenario shown on the screen at the time the file was saved. 

 

·             Open .CRS File – Calls up a Dialog box, which Opens any pre-existing .CRS file and displays the output results.

 

·             Save .CRS File – Calls up a Dialog box, which Saves data on the screen to files with any user-selectable filenames.  This is independent of the automatic saving as “LastFile.CRS” of the data at the close of this module or the close of the program.

 

·             Exemplar Test – Computes A, B, and G coefficients of Stiffness (see Inputs above)

 

·             Graphics Suite – Graphic display of each vehicle, both vehicles side-by-side and both vehicles positioned with the centroids overlapped. Vector lines show PDOF, moment arms and DeltaV direction.  If Angles are given the Graphics include a Momentum diagram that includes PDOF/DeltaV.  [Esc] to Exit

 

·             Formulae – Opens a word processor (set by the user in Setup) with a file showing the basic formulae use in this module of the program.  While the user may add to or modify the information in this file, it does not change the formulae imbedded into the program.

 

·             N – This button toggles a graphical number pad on the screen that can be used to enter data into the input boxes without using your keyboard number pad.  This may be useful for presentations as data entry can be accomplished using a wired/wireless mouse.

 

·             [> 360LM] – With the Speeds computed after the Angles have been input, the appropriate information can be transferred to the 360 Linear Momentum module using the [> 360LM] button.  CRUSH passes enough information to 360LM to process and send data to SMAC-RT with the information to position the collision interface.

 

Additional Information:

 

CRASH3 Technical Manual – Internet

 

IPTM Publications – The following publications are available from IPTM 1-904-620-4786  or  http://www.iptm.org and are recommended for further reading.

 

ANATOMY of a COLLISION by George M. Bonnett contains an article entitled Stiffness Coefficients – Energy and Damage, detailing this process.     

UNDERSTANDING   DELTAV   FROM   DAMAGE – Discussion includes Crash3 formulae and computations for non-equidistant "C" measurements.

BEYOND   CRASH3  --  DELTAV   FROM   DAMAGE - Discussion of depth "zones" for non-linear crush and modeling of bullet-shaped or curved vehicles.