Crash Data Presentation Texas Association of Accident ...tucrrc.utulsa.edu/members/Inline - Sebring...

Crash Data Presentation Texas Association of Accident Reconstruction

Specialists Conference

2014

Consortium Website

All data from crash testing and this presentation will be available at

http://tucrrc.utulsa.edu

Credentials

User: TUCRRCmember Password: TUCRRCpassword

TAARS 2014 http://tucrrc.utulsa.edu 2

http://tucrrc.utulsa.edu/

Running into Trailers

Common theme for crash testing

IPTM 2004

IPTM 2012

IATAI 2013

Tennessee 2014

TAARS 2014

Common occurrence on highways and interstates.


Order of Presentation

Crash Test Videos

Crash Testing Setup and Instrumentation

Rotational Mechanics Analysis

Restitution Analysis

Aggregated Crash Test Analysis


Tennessee 2014


IPTM Special Problems


IPTM Special Project


TAARS 2014

Open Quicktime to watch videos


TAARS 2014 Summary

Crash 1

2005 Chrysler Sebring

Weight: 3395

Impact Speed

Vbox 3i: 46.11

Video Vbox: 45.66 mph

eGPS-200: 45.86

Crash 2

2004 Mercury Sable

Weight: 3043 lb

Impact Speed

Vbox 3i: 45.98

Rear Dual Displacement 13.5 ft

Angle of trailer rotation: ~24.5 deg


DATA ACQUISITION SYSTEMS AND SETUP


Racelogic VBox 3i

100Hz GPS system

Serial (CAN) communication

Compact flash logging

Brake trigger

Inertial Measurement Unit

Tri-axial accelerometer

Tri-axial gyroscope


Racelogic Video VBox

10Hz/20Hz GPS system

4 Cameras

Microphone

Compact flash logging


eDAQ Data Acquisition

Rugged system designed for use in harsh environments

Enables simultaneous and synchronous recording of multiple channels with different types of instruments

Convenient data recording modes

Proprietary interface

Infield Software http://www.hbm.com/en/menu/support/software-firmware-downloads/data-acquisition-systems/somat/#c33997


http://www.hbm.com/en/menu/support/software-firmware-downloads/data-acquisition-systems/somat/#c33997










eDAQ


4 Layers

DIO

Digital I/O

HLS

High level analog

ECOM

Vehicle network communications

Instruments


eGPS-200Plus Combines data from 2 GPS antennas and IMU to

provide several kinematic measurements at 200Hz

Measurements Acceleration (All 3 axis)

Angular velocity (All 3 Axis)

Speed

Heading, altitude, longitude

Slip angle

Instruments

Gyroscope Tri-axial measurements

±600 deg/s rates

400 Hz bandwidth


Accelerometer Tri-axial measurements

±250gs

5,000 Hz bandwidth

eDAQ Data Recording Modes

Time history

Records continuously

Burst history

Buffer data

Records data in a

predefined interval

Simplifies data

processing


Interface (Web)


Limited access

Manage networked cameras

Quick test startup

VC4000DAQ


10Hz GPS

Brake pedal sensor

Tri-axial accelerometer

Used to determine drag coefficient

Attaching Accelerometer


SAE Sign Convention

MATAI 2014 http://tucrrc.utulsa.edu 22

INLINE IMPACT CHRYSLER SEBRING INTO TRAILER

Crash Test 1 Data


System Momentum

System Momentum In + External Impulse = System Momentum Out

Planar components: X, Y, and q.

A system is defined as something you can define a boundary with.

Consistent boundary (Eularian system)

Consistent Objects (Lagrangian system)

Forces act on boundaries.


Inline system

System defined as the two vehicles where the interaction boundary is the road surface.

External impulses occur at the boundary.

Don’t need to include collision forces

Can also define the boundaries around each vehicle.

Need to include both collision forces and road forces.


Foundations

Work and Energy: Kinetic Energy In = Damage Energy + Kinetic

Energy Out

Impulse and Momentum Momentum In + External Impulse = Momentum Out

External Impulse can be from collision forces and friction

Kinematics Speed in + Delta V = Speed Out

Restitution = (V1,in – V2,in)/(V2,out – V1,out)


DATA FROM INSTRUMENTS

Inline Crash


Vbox 3i Data


eDAQ Synchronized Data


eDAQlite_Data_Crash1_TX2014.sif - eGPS@speed_3d.RN_1

spee

d_3d

(km

/h)

01020304050607080

eDAQlite_Data_Crash1_TX2014.sif - [email protected]_1

VB

Vel

ocity

(kno

ts)

0

10

20

30

40

50

eDAQlite_Data_Crash1_TX2014.sif - IMU@accel_x_05.RN_1

Time(secs)

90 92 94 96 98 100 102

acce

l_x_

05(g

)

-120-100-80-60-40-200

2040

Impact Speeds


eDAQlite_Data_Crash1_TX2014.sif - eGPS@speed_3d.RN_1

spee

d_3d

(km

/h)

01020304050607080

eDAQlite_Data_Crash1_TX2014.sif - [email protected]_1

VB

Vel

ocity

(kno

ts)

0

10

20

30

40

50


Time(secs)

101.0 101.2 101.4 101.6 101.8

acce

l_x_

05(g

)

-120-100-80-60-40-200

2040

x:101.185 y:73.8 n:4942

x:101.18 y:40.17 n:2470

x:101.1842 y:0.257583 n:198546

45.86 mph

46.22 mph

Crash Pulse from Chrysler



Time(secs)

101.20 101.25 101.30 101.35 101.40 101.45

acce

l_x_

05(g

)

-120

-100

-80

-60

-40

-20

0

20

40x:101.185 y:0.322577 n:198550 x:101.3286 y:0.0347443 dx:0.1436 dy:-0.287833

Chrysler Delta V in X


Calculator_00220.sif - Computed from X Accelerometer

Time(secs)

101.1 101.2 101.3 101.4 101.5 101.6

Del

ta V

(mph

)

-50

-40

-30

-20

-10

0

10x:101.186 y:-0.0167915 n:256 x:101.3254 y:-49.5999 dx:0.1394 dy:-49.5831

Delta V = -49.6 mph

Delta T = 139 msec

Separation after impact


Relative Accelerations


eDAQ_Data_crash1_TX2014.sie - IMU_data@Accel_X_06.RN_1

Acc

el_X

_06(

g)

-200-150-100-500

50100150


Acc

el_X

_43(

g)

-8-6-4-202468

10

eDAQ_Data_crash1_TX2014.sie - GPS@accel_x.RN_1

Time(secs)

402.0 402.5 403.0 403.5 404.0 404.5

acce

l_x(

G)

-3-2-101234

Near Impact

Middle of Trailer

Tractor Platform

Same Scale (X Direction)



Acc

el_X

_06(

g)

-40

-20

0

20

40


Acc

el_X

_43(

g)

-40

-20

0

20

40

eDAQ_Data_crash1_TX2014.sie - GPS@accel_x.RN_1

Time(secs)

402.4 402.6 402.8 403.0 403.2 403.4 403.6 403.8

acce

l_x(

G)

-40

-20

0

20

40

Y Axis Accelerations


eDAQ_Data_crash1_TX2014.sie - IMU_data@Accel_Y_06.RN_1

Time(secs)

402.4 402.6 402.8 403.0 403.2 403.4 403.6

Acc

el_Y

_06(

g)

-36

-12

12

36


eDAQ_Data_crash1_TX2014.sie - GPS@accel_y.RN_1

Z- Axis Accelerations


eDAQ_Data_crash1_TX2014.sie - IMU_data@Accel_Z_06.RN_1

Time(secs)

402.5 403.0 403.5 404.0

Acc

el_Z

_06(

g)

-40

-20

0

20

40

eDAQ_Data_crash1_TX2014.sie - IMU_data@Accel_Z_43.RN_1

eDAQ_Data_crash1_TX2014.sie - GPS@accel_z.RN_1

Delta-V in X from all Accels


Rear X Accel.

Time(secs)

402.0 402.5 403.0 403.5 404.0 404.5 405.0 405.5

Del

ta V

(mph

)

-3

-2

-1

0

1

2

3

4

5

Middle X Accel.

Tractor Accel (e-GPS)

x:402.3874 y:0.010843 n:441

x:402.3874 y:0.00528648 n:616

x:402.385 y:0.008784 n:72

x:402.5234 y:4.31572 dx:0.136 dy:4.30488

x:402.5234 y:4.30905 dx:0.136 dy:4.30377

x:402.525 y:4.09444 dx:0.14 dy:4.08566

Zoomed in on Delta-V (4.3 mph in 115 msec)


Rear X Accel.

Time(secs)

402.30 402.35 402.40 402.45 402.50 402.55 402.60 402.65

Del

ta V

(mph

)

-1

0

1

2

3

4

5

Middle X Accel.

Tractor Accel (e-GPS)

x:402.4026 y:0.0406617 n:517

x:402.4026 y:-0.000231389 n:692

x:402.405 y:-0.001098 n:76

x:402.5176 y:4.29468 dx:0.115 dy:4.25402

x:402.5176 y:4.36877 dx:0.115 dy:4.369

x:402.52 y:4.15373 dx:0.115 dy:4.15483

Observations

Rigid body assumption:

Common delta-V values for the whole rig

Common times

Confidence of measurements

Acceleration data shows shock attenuation

150 g’s near impact

4 g’s at cab

eGPS accelerometer has too much damping (not great for shock events)


Restitution

Impact speed of car: 46 mph

Delta V of Car: 49.6 mph

Post impact Speed of car: -3.6 mph (~0)

Impact Speed of Trailer: 0 mph

Post Impact Speed (Delta V) of Trailer: 4.3 mph

𝑒 =𝑉1,𝑜𝑢𝑡−𝑉2,𝑜𝑢𝑡

𝑉2,𝑖𝑛−𝑉1,𝑖𝑛=−3.6−4.3

0−46= 0.172


Reconstruction Strategy

Assume known speed of tractor-trailer

If not an underride: Calculate Delta V from Crush

Assume restitution of 0.1-0.2 for impact speed

If underride: Look for EDR data…

Crush analysis doesn’t account for some energies.

50% low estimate on impact speed for Chrysler in this case.

Closing speeds are almost always low.


SABLE INTO TRAILER DUALS AT 90 DEGREES

TAARS 2014 Crash #2:


Crash 2 Video


Fundamentals of Crash Reconstruction

Chapter 9: Rotational Mechanics


Tractor Trailer Axle Data

Weights


Tractor Trailer Weights (lb)

Left Front Right

4820 |- -| 4480

2900 |- -| 3320

2320 |- -| 2180

2040 |- -| 1750

2300 |- -| 2300

Axle Weights (lb)

Left Front Right

4820 |- Steer -| 4480

2900 |- Drive 1 -| 3320

2320 |- Drive 2 -| 2180

2040 |- Trailer 1 -| 1750

2300 |- Trailer 2 -| 2300

Total: 28,410 lb

Portable Scales

Weights from Wrecker

Box Van Landing gear: 4640 lb

Box Van Rear Axles: 7800 lb

Volvo Steer Axle: 8200 lb

Volvo Drive Axles: 7240 lb

Total Combined Weight: 27,880 lb Compared to 28,410 lb from other scales (2%

difference)

Mercury Sable: 2968 + 75 = 3043 lb

Chrysler Sebring: 3320 + 75 = 3395 lb


Mercury Impact Speed ~46 mph (Crash 2)


Delta V: ~38 mph


Rear Dual Displacement


Angle of Rotation


24.6 Deg

What About Trailer Rotation?

Assume the Trailer is a Rigid Body rotating around the king pin

Tractor did move a little

Trailer had rolling motion

Angular quantities are the same everywhere

Acceleration of Rigid Body 𝑎 𝑃 = 𝑎 𝑂 + 𝛼 × 𝑟 𝑃/𝑂 + 𝜔 × (𝜔 × 𝑟 𝑃/𝑂)

Y direction accel. depends on lever arm


𝜔 × (𝜔 × 𝑟 𝑃/𝑂)

Graphic of Rotation


x

y

+q 𝑟

𝛼 × 𝑟 𝑃/𝑂

Y Axis Accelerations



Time(secs)

784.0 784.5 785.0

Acc

el_Y

_06(

g)

-150

-100

-50

0

50

100

150


eDAQ_Data_crash2_TX2014.sie - GPS@accel_y.RN_1

Note: Middle Accelerometer

(blue) was mounted with z axis

up and y axis out driver’s side

(opposite SAE).

Zoomed on Y Accelerations


Rear Trailler Accelerometer (Y)

Time(secs)

783.70 783.75 783.80 783.85 783.90 783.95 784.00

Acc

eler

atio

n (g

)

-100

-67

-33

0

33

67

100

Middle Accelerometer (Y)

Tractor Accelerometer (Y)

Delta V in Y for Tractor


Tractor Accelerometer in Y

Time(secs)

782 784 786 788 790 792 794

Del

ta V

(m

ph)

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0x:793.056 y:No Data n:No Data

Delta V in Y for Trailer Middle


Calculator_00248.sif - Calculated from Middle Y Accel

Time(secs)

783 784 785 786 787 788 789 790

Del

ta V

(mph

)

-10

-8

-6

-4

-2

0

2

Delta V in Y near Impact


Calculated from Y Accel near impact

Time(secs)

783.5 784.0 784.5 785.0 785.5 786.0 786.5 787.0 787.5

Del

ta V

(m

ph)

-20

-15

-10

-5

0

5

Delta V Comparison


Calculator_00239.sif - Tractor Y Accel

Time(secs)

784.0 784.5 785.0 785.5 786.0

Del

ta V

(m

ph)

-20

-15

-10

-5

0

5

Calculator_00247.sif - Impact Y Accel

Calculator_00248.sif - Middle Y Accel

Trailer Crash Pulse


Calculator_00239.sif - Tractor Y Accel

Time(secs)

783.70 783.75 783.80 783.85 783.90

Del

ta V

(m

ph)

-20

-15

-10

-5

0

5

Calculator_00247.sif - Impact Y Accel

Calculator_00248.sif - Middle Y Accel

x:783.7 y:-0.000373315 n:32

x:783.699 y:-0.106395 n:648

x:783.699 y:-0.020098 n:555

x:783.79 y:0.206446 dx:0.09 dy:0.206819

x:783.7876 y:-17.6722 dx:0.0886 dy:-17.5658

x:783.7876 y:-8.25392 dx:0.0886 dy:-8.23382

88 ms

-8.23 mph

-17.55 mph

Yaw and Roll Rate of Trailer


eDAQ_Data_crash2_TX2014.sie - IMU_data@Yaw_48.RN_1

Yaw

_48(

deg/

sec)

-150-100-500

50100150200

eDAQ_Data_crash2_TX2014.sie - IMU_data@Roll_48.RN_1

Rol

l_48

(deg

/sec

)

-150-100-500

50100150200250


Time(secs)

784.0 784.5 785.0 785.5 786.0 786.5

Acc

el_Y

_43(

g)

-30

-20

-10

0

10

20

30

Trailer to Truck Yaw Rate Comparison


eDAQ_Data_crash2_TX2014.sie - IMU_data@Yaw_48.RN_1

Time(secs)

784.0 784.5 785.0 785.5 786.0

Yaw

_48(

deg/

sec)

-150

-100

-50

0

50

100

150

200eDAQ_Data_crash2_TX2014.sie - GPS@yaw_rate.RN_1

Yaw and Roll Rate


eDAQ_Data_crash2_TX2014.sie - IMU_data@Roll_48.RN_1

Time(secs)

784.0 784.5 785.0 785.5 786.0 786.5 787.0

Rol

l_48

(deg

/sec

)

-150

-100

-50

0

50

100

150

200

250eDAQ_Data_crash2_TX2014.sie - IMU_data@Yaw_48.RN_1

Restitution


Yaw and Roll Angle


Calculator_00251.sif - Yaw Angle

Time(secs)

783.0 783.5 784.0 784.5 785.0 785.5 786.0 786.5 787.0 787.5

Ang

le(d

eg)

-15

-10

-5

0

5

10

15

20

25Calculator_00252.sif - Roll Angle

Estimate Initial average Angular Velocity


Calculator_00251.sif - Yaw Angle

Time(secs)

784.0 784.5 785.0 785.5

Ang

le(d

eg)

-15

-10

-5

0

5

10

15

20

25Calculator_00252.sif - Roll Angle

x:783.7794 y:2.19715 n:1254

x:783.7794 y:3.67005 n:1579

x:783.8794 y:5.98207 dx:0.1 dy:3.78492

x:783.8794 y:6.14531 dx:0.1 dy:2.47526

Slope = 37.84 deg/s

Mercury Speed


Restitution Estimation

Mercury Impact Speed: 46 mph

Mercury Post Impact Speed: ~8 mph

Post Impact Point Velocity: ~16 mph

𝑒 =𝑉1,𝑜𝑢𝑡 − 𝑉2,𝑜𝑢𝑡𝑉2,𝑖𝑛 − 𝑉1,𝑖𝑛

≈8 − 16

0 − 46= 0.17


Inertial Properties of Trailer

http://deepblue.lib.umich.edu/handle/2027.42/118

Moment of Inertia

945,019 in-lb-sec2


Page 148

Actual Crash Weight: 12,440 lb


Center of Mass Location


TENNESSEE CONFERENCE 2014

Comparison to other Crashes


Tennessee 2014


Mapping data


EDR DATA FROM UNDERRIDES


GMC Envoy Crash Video


No Air Bag Deployment


Photo of Non-deployment


GMC Envoy Pre-Crash Data


GMC Envoy ABS and Δv Crash Data


GMC Envoy EDR Δv


-45

-40

-35

-30

-25

-20

-15

-10

-5

0

0 100 200 300 400

Δv (

mph)

Time (ms)

GMC Envoy Δv vs. Time CDR

Accuracy of EDR Data


To test accuracy of EDR Data a reference accelerometer was mounted behind the passenger seat of the crash vehicle

GMC Envoy Crash Acceleration Impulse


-100

-80

-60

-40

-20

0

20

40

60

80

0 50 100 150 200 250

Acc

ele

ration (

g)

Time (ms)

Crash Impulse Acceleration Accelerometer

GMC Envoy Δv comparison


-45

-40

-35

-30

-25

-20

-15

-10

-5

0

0 50 100 150 200 250 300 350 400

Δv (

mph)

Time (ms)

GMC Envoy Δv vs. Time Accelerometer CDR

Maximum

recorded

velocity

change

Chevy S10 Δv comparison


-45

-40

-35

-30

-25

-20

-15

-10

-5

0

0 50 100 150 200 250

Δv (

mph)

Time (ms)

Chevy S10 Δv vs. Time Accelerometer CDR

Accuracy of EDR Data

Based on the data provided by the reference accelerometer, the EDR Δv is accurate

Similar shape in Δv vs. time graphs validate EDR data

Trend line can be used to extrapolate data past the 150ms memory threshold


When do air bags deploy?

At the onset of an event, the ACM detects acceleration sufficient to wakeup the crash sensing / decision making algorithm

Based on an evaluation of the sensed acceleration, potentially along information from auxiliary sensors, the ACM makes a decision to Deploy or Not Deploy the supplemental restraints


Predictive Decision Making

The ACM decision is anticipatory based on pre-programmed criteria

“Jerk” and other criteria are evaluated as long as the crash sensing algorithm is awake

It does not / can not wait for some minimum delta-v threshold to be met

Deployment decision has to be made early to allow time for airbag inflation


Ideal Airbag Deployment Timing

It is generally held the ideal decision window is ~15-50ms to allow for airbag inflation before occupant contact


Deployment Timing Example


Less than ideal timeline


When air bags may not deploy


THP 2014 - Crash #1


Leica ScanStation Data


THP 2014 - Crash #1


THP 2014 - Crash #2


Chevy S10 Crash Video


Displacement Angle


King-pin

Rear axle

37.6

θ

7.8

𝜃 = 𝑡𝑎𝑛−17.8

37.6= 0.204 𝑟𝑎𝑑 = 11.72°

(Top View)

7.8

37.6

θ

Chevy S10 Pre-Crash Data


Chevy S10 ABS and Δv Crash Data


Chevy S10 EDR Δv


-45

-40

-35

-30

-25

-20

-15

-10

-5

0

0 20 40 60 80 100 120

Δv (

mph)

Time (ms)

Chevy S10 Δv vs. Time CDR

Combined EDR Δv


-45

-40

-35

-30

-25

-20

-15

-10

-5

0

0 50 100 150 200 250 300 350 400

Δv (

mph)

Time (ms)

Chevy S10 and GMC Envoy Δv vs. Time

GMC Envoy Chevy S10

Jerk Defined

In physics:

also known as jolt, surge, or lurch

Jerk = the rate of change of acceleration

the derivative of acceleration with respect to time

the second derivative of velocity

the third derivative of position.


Jerk – Related to Airbag Deployment Decision Making


DETROIT DIESEL ECM DATA AND NETWORK TRAFFIC

Jeremy Daily on


DDEC Reports


Graph Data


Table Data


Detroit Diesel Diagnostic Link DDDL

Compare ECM Time Clock


Speed Record Comparison


Remarks

Impulse and Momentum data is insufficient to calculate speeds

DeltaV from hvEDR data is not resolved well

Vehicle Network speed has more samples, thus making it a candidate for data, if available.

hvEDR follows the J1587 Road Speed Data.


ROTATIONAL MECHANICS ANALYSIS FOR RIGHT ANGLE IMPACT


S-10 Crash Analysis


• Location of Center of Mass of Trailer • Mass Moment of Inertia of Trailer • Lateral Displacement of Trailer

(Displacement Angle) • Angular Velocity of Trailer • Calculating S-10 delta-V • Calculating pre-impact velocity of S-10 • Accuracy of Calculations vs.

Equipment Data

Determining the location of Center of Mass (C.M.) using Static Analysis


WRA1 WRA2 WLG

W Location Left Right

LG Landing Gear 3800 4400

RA1 Rear Axle 2600 1800

RA2 Front Axle 2200 1900

Total Trailer Weight (Wtotal) =

16,700 lb.

WTOTAL



50.3 ft.

9.6

13.6

38

47.2

d1

d2

d3

d4



WRA1 WRA2 WLG

WTOTAL O x

y

𝑀𝑂 = 0

x

d1

d2

d3

𝑊𝑅𝐴1(𝑑1) +𝑊𝑅𝐴2(𝑑2) −𝑊𝑇𝑂𝑇𝐴𝐿(𝑋) +𝑊𝐿𝐺(𝑑3) = 0



WRA1 WRA2 WLG

WTOTAL O x

y

x

d1

d2

d3

𝑋 =𝑊𝑅𝐴1(𝑑1) +𝑊𝑅𝐴2(𝑑2) +𝑊𝐿𝐺(𝑑3)

𝑊𝑇𝑂𝑇𝐴𝐿

Location of C.M.

from the rear of the

trailer.



WRA1 WRA2 WLG

WTOTAL O x

y

24.5

d1

d2

d3

𝑋 = 24.5 𝑓𝑡 Location of C.M.

from the rear of the

trailer.

Displacement Angle


37.6

θ

7.8

7.75ft

Rotational Mechanics- Mass Moment of Inertia


• Def: Measure of a body’s

resistance to rotational

acceleration about a

specified axis of rotation.

• Depends on geometry and

location of axis of rotation.

• If axis of rotation is NOT

through center of mass,

then Parallel Axis Theorem

must be used.

Rotational Mechanics- Mass Moment of Inertia (Yaw)


𝐼𝑧 =1

12𝑚(𝑏2 + 𝐿2)

m…mass

b…width of trailer

L…length of trailer

Units: lb-ft-s2 , slug-ft2

𝐼𝑧,𝐶𝑀 =1

12(16700

32.2)(8.52 + 50.32)

𝐼𝑧,𝐶𝑀 = 112,471.73 𝑙𝑏 ∙ 𝑓𝑡 ∙ 𝑠2

Rotational Mechanics- Parallel Axis Theorem


King-pin

d=22.6

𝐼𝑧,𝐾𝑃 = 𝐼𝑧,𝐾𝑃 +𝑚𝑑2

𝐼𝑧,𝐾𝑃 = 112,471.73 + (16700

32.2)(22.62)

𝐼𝑧,𝐾𝑃 = 378,308.8 𝑙𝑏 ∙ 𝑓𝑡 ∙ 𝑠2

Rotational Mechanics- Angular Velocity


King-pin

PDOF

(Center of Axle

Assy.)

h = 35.3

Assumptions:

-50/50 Left/Right Weight Distribution

-Fully rigid king-pin

-Estimate drag-factor (f)

𝜔 = 2𝑤𝑓ℎ𝜃

𝐼𝑧,𝑘𝑝 (eq. 9.67)

f…estimated drag factor (0.6-0.7)

w…weight

h…KP to LOI θ…displacement angle I…mass moment of inertia about the King-pin

Rotational Mechanics- Angular Velocity


King-pin

PDOF

(Center of Axle

Assy.)

h = 35.3

𝜔 = 2(0.7)(16700)(35.3)(0.204)

378308.8

𝜔 = 0.534857 rad/sec

𝜔

Plug in numbers…

Delta-V of S-10


King-pin

PDOF

(Center of Axle

Assy.)

h = 35.3

∆𝑣 =𝐼𝑧,𝑘𝑝𝜔

𝑚ℎ

∆𝑣 =(378,308.8)(0.535)

(343032.2)(35.3)

∆𝑣 = 53.9𝑓𝑡

𝑠= 36.7 𝑚𝑝ℎ

(eq. 9.60)

Pre-Impact Velocity of S-10 (v1)


𝑣1 =𝑣4 + ∆𝑣

1 + 𝑒

𝑣4 = ℎ𝜔

𝑣1 =35.3 0.535 + 53.9

1 + 0

(eq. 9.72)

…linear post-impact velocity of trailer

𝑣1 = 72.7 𝑓𝑡/ sec = 49.62 𝑚𝑝ℎ

𝑣1 𝑣4

𝑒 …Coefficient of restitution (typically 0 - 0.15).

Ratio of speeds after and before impact. 1 –

elastic & 0 – perfectly inelastic.

Calculations vs. Instrument Data


Calculated Radar eGPS-200 VBOX 3i VVBOX Lite

49.62 48.7 48.72 49.04 48.75

f v1

0.6 45.94

0.65 47.81

0.7 49.62

Calculated Instruments

[mph]

This demonstrates that the principles based on Newtonian

physics hold true with a small margin of error. Often times,

this is all we have to rely on when no other facts/data are

available.

Consortium Website

All data from crash testing and this presentation will be available at

http://tucrrc.utulsa.edu

Credentials

User: TUCRRCmember Password: TUCRRCpassword


http://tucrrc.utulsa.edu/

THANK YOU

Safe Travels.


Crash Data Presentation Texas Association of Accident ...tucrrc.utulsa.edu/members/Inline - Sebring...

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