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Communications in Information Science and Management Engineering DOI No.: 10.5963/CISME0110005

CISME Vol.1 No.10 2011 PP.22-26 www.jcisme.org C 2011 World Academic Publishing

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The Effects of Material Properties on Rebound

Characteristics of Deris in Automobile CrashZhan-yu Wang

1, Xue-jing Du

1, Hong-guo Xu

2

1College of Traffic, Northeast Forestry University, China

2College of Transportation, JiLin University, [email protected];[email protected];

[email protected]

Abstract-In order to study the effects of material

properties on rebound characteristics of debris in different

thrown condition, and promote the dynamic behavior

model of debris further in automobile crash, the dynamic

rule of elastic and elastic-plastics rebound parameters

vary with thrown condition are obtained by kinetic

simulation analysis. The rebound parameters indexes are

vertical rebound coefficient, horizontal rebound

coefficient, angle lost coefficient. The effects of rebound

characteristics on dynamic behavior after collision arediscovered. The trend curves of different material nature

varying with rebound parameters are given by combing

qualitative analysis with quantitative calculation. The

abnormal phenomena of debriss motion just like breaking

rebound, is expounded. The results of simulation tests

show that the rebound parameters of elastic-plastic debris

vary with thrown velocity and thrown angle in non-linear,

but in linear with thrown height. Sometimes the rebound

parameters of elastic-plastic debris are higher than 1.

Then, the rebound parameters of elastic debris vary with

thrown height in non-linear, and the change trends is

closed. The vertical rebound coefficient, the horizontal

rebound coefficient, and the rebound coefficient of elasticdebris vary with thrown angle upward with small change

ranges, but big change ranges in downward.

Keywords-automobile crash; thrown debris; rebound

character;dynamic simulation

I. INTRODUCTION

Debris in automobile crash implies much informationabout traffic accident. The rebound parameters indexes are

vertical rebound coefficient ne , horizontal rebound

coefficient te , angle lost coefficient af that can not only

connection collision velocity with collision deformation,

impact force, and energy loss but also reflect the internalrelation among factors in the process of traffic accident. Aswell as Rebound parameters are convenient to solve collision

parameters and are often used as the criterion of controllingand verifying for accident reconstruction [1]. The classicalcollision theory of Newton has laid foundation for collisionvelocitys solving [2]. With the constantly rising of trafficaccident rate and the improvement of technology requirementfor accident reconstruction, impact test of real car is taken asmethod to study rebound characteristics of automobile incrash [3]. However, experiment data obtained from real car

collision is limited by experiments quantity. At present, somemathematical models of collision are used to describe therelationship between rebound parameters, the value anddirection of relative velocity, as well as collision angle [4,5].But the effect of thrown condition on rebound characteristicsof debris in crash has no reported. Based on this status, therelationship between rebound characteristics and throwncondition is studied through the test performed by dynamicsimulation model built with Ansys/Ls-Dyna. Based on theresults of test, rebound parameters in different thrown

condition are calculated, trend curves of rebound parametersvarying with thrown condition are obtained by discovering therule of rebound characteristics of elastic-plastic debris, whichis significant for the better accuracy dynamic behavior modelof debris in automobile crashs establishing, and trafficaccidents reconstructing.

II. SIMULATION MODEL

A. Kinetic Simulation Model

At the moment of collision, debris dropped from vehiclehas independent motion each other. Based on this status,taking single independent elastic, elastic-plastic, plastic debrisas study object, which diameter is from 1.0 centimeter to 2.5

centimeter. The kinetic simulation model is established by themethod of transient dynamic analysis with Ansys/Ls-Dyna,which includes two parts. One is elastic-plastic debris left inautomobile crash made up of exhibition 3D Solid 164 inDYNA. The other is target surface, with which debris contactnon-line is rigid pavement. Figure 1 is kinetic simulationmodel of debris in automobile crash.

Figure 1. Kinetic Simulation Model of Debris

B. Model Reliability

The reliability of Ansys/Ls-Dyna models has been verifiedby real engineering cases before [6]. However,Ansys/Ls-Dyna model applied on analyzing dynamic

behavior has never been reported. Take massive consolidationclay given in the essay [7] as study object to verify theeffectiveness of kinetic simulation model of debris in
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0.89

elastic 0.191 0.842 0.628 4.870 3.060 43.130 12.011 0.279

elastic-

plastic0.424 0.704 0.575 4.948 2.845 46.320 32.210 0.695

0.10

elastic 0.435 0.873 0.809 3.344 2.706 25.740 13.492 0.524

elastic-plastic

0.308 0.685 0.508 5.016 2.549 48.590 27.010 0.556

0.11

elastic 0.497 0.930 0.913 2.640 2.412 13.006 7.028 0.540

elastic-plastic 1.875 0.834 0.977 2.700 2.638 17.660 35.590 2.015

0.15

elastic 0.107 0.785 0.544 3.939 2.142 46.682 8.241 0.177

elastic-

plastic0.359 0.603 0.447 5.335 2.386 56.580 42.090 0.744

0.20

elastic 0.486 0.492 0.487 5.658 2.757 62.251 61.946 0.995

elastic-plastic

0.220 0.577 0.333 5.647 1.879 62.130 35.820 0.577

TABLE 3. REBOUND PARAMETERS VARYING WITH THROWNANGLE OF ELASTIC AND ELASTIC-PLASTIC DEBRIS

/() material ne te e iV /

(ms-1)

rV /

(ms-1) /() /() f

70 elastic 6.679 1.001 6.621 4.758 31.505 82.388 88.853 1.079elastic-

plastic0.459 1.770 0.509 4.786 2.435 82.650 63.570 0.769

60

elastic 0.886 0.338 0.829 0.711 0.590 67.568 81.045 1.200

elastic-plastic

0.151 0.658 0.197 4.812 0.948 78.650 48.920 0.622

45

elastic 0.068 0.514 0.203 3.755 0.760 67.990 18.100 0.266

elastic-

plastic1.070 0.544 0.927 1.795 1.665 54.600 70.140 1.285

30

elastic 0.536 0.653 0.586 3.027 1.773 50.509 44.872 0.888

elastic-

plastic1.043 0.633 0.838 2.276 1.906 41.460 55.490 1.338

15

elastic 2.053 0.910 0.947 2.347 2.223 8.265 18.157 2.197

elastic-plastic

0.391 0.632 0.493 4.676 2.303 52.890 39.320 0.743

0

elastic 0.274 0.858 0.654 4.869 3.184 43.082 16.652 0.387

elastic-

plastic0.424 0.704 0.575 4.948 2.845 46.320 32.210 0.695

-15

elastic 0.085 0.979 0.971 3.246 3.150 7.636 0.669 0.088

elastic-plastic

0.440 0.710 0.589 5.308 3.124 45.520 32.250 0.709

-30

elastic 0.088 0.807 0.560 5.387 3.016 46.432 6.518 0.140

elastic-

plastic0.922 0.725 0.791 3.972 3.142 33.870 40.480 1.195

-45

elastic 0.133 0.737 0.491 4.472 2.197 49.252 11.811 0.240

elastic-

plastic 0.395 0.582 0.456 5.807 2.647 57.740 47.050 0.815

-60

elastic 0.080 0.699 0.423 2.952 1.248 53.277 8.656 0.163

elastic-plastic

0.459 0.368 0.447 5.933 2.650 67.540 71.650 1.061

-70

elastic 0.105 0.378 0.144 5.891 0.850 74.194 44.564 0.601

elastic-

plastic0.431 0.139 0.575 5.979 2.497 74.840 85.010 1.136

C. Results Analysis

From figure 3 to figure 14 are curves of reboundparameters varying with thrown condition.

Figure 3. Vertical rebound coefficient vary with

thrown velocity

0

0.1

0.2

0.3

0.4

0.5

8.92 9.64 9.67 10.3 10.8 11.5

Velocity/(ms-1)

Verticalrebound

coefficient

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

elastic-plastic

elastic

Figure 4. Horizontal rebound coefficient vary with

thrown velocity

0.84

0.85

0.86

0.87

0.88

0.89

0.9

0.91

0.92

0.93

8.92 9.64 9.67 10.3 10.8 11.5

Velocity/(ms-1)

Horizo

ntalrebound

co

efficient

elastic

elastic-plastic

Figure 5. Rebound coefficient vary with thrown

velocity

0.7

0.75

0.8

0.85

0.9

8.92 9.64 9.67 10.3 10.8 11.5

Velocity/(ms-1)

Reboundco

efficient

elastic

elastic-plastic

Figure 6. Angle lost coefficient vary with t hrown

velocity

0

0.05

0.1

0.15

0.2

0.25

8.92 9.64 9.67 10.3 10.8 11.5

Velocity/(ms-1)

Anglelostcoefficient

0

0.1

0.2

0.3

0.4

0.5

0.6

elastic-plastic

elastic

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thrown height

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

0.8 0.89 1 1.1 1.5 2

Height/(m)

Ver

ticalreboundcoefficient

elastic

elastic-plastic


thrown height

0.4

0.5

0.6

0.7

0.8

0.9

1

0.8 0.89 1 1.1 1.5 2

Height/(m)

Horizontalrebound

coefficient

elastic

elastic-plastic


height

0

0.2

0.4

0.6

0.8

1

1.2

0.8 0.89 1 1.1 1.5 2

Height/(m)

Rebound

coefficient

elastic

elastic-plastic

Figure 10. Angle lost coefficient vary with thrown

height

0

0.5

1

1.5

2

2.5

0.8 0.89 1 1.1 1.5 2

Height/(m)


elastic

elastic-plastic


thrown angle

0

1

2

3

4

5

6

7

70 60 45 30 15 0 -15 -30 -45 -60 -70

Angle/()

Ve

rticalreboundcoefficient

elastic

elastic-plastic


thrown angle

0

0.2

0.40.6

0.8

1

1.2

1.4

1.6

1.8

70 60 45 30 15 0 -15 -30 -45 -60 -70

Angle/()

Horizontalrebound

coefficient

elastic

elastic-plastic


angle

0

1

2

3

4

5

6

7

70 60 45 30 15 0 -15 -30 -45 -60 -70

Angle/()

Reboundc

oefficient

elastic

elastic-plastic

Figure 14. Angle lost coefficient vary with t hrown

angle

0

0.5

1

1.5

2

2.5

70 60 45 30 15 0 -15 -30 -45 -60 -70

Angle/()


elastic

elastic-plastic

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From figure 3 to figure 6 are curves of rebound parametersvarying with thrown velocity. It can be seen that the rebound

parameters of elastic-plastic debris vary with thrown velocityin non-linear, the trend curve and the value of vertical reboundcoefficient and angle lost coefficient are proximity about 0.2,the trend curve of horizontal rebound coefficient and reboundcoefficient is close, which illustrates that horizontal reboundcoefficient is the key factors affecting rebound coefficient.

However, the rebound parameters of elastic debris vary withvelocity in linear slowly. The vertical rebound coefficient islow in the scope of [0.1, 0.5]. The horizontal reboundcoefficient and the rebound coefficient change around 0.9.

From figure 7 to figure 10 are curves of reboundparameters varying with thrown height. It can be seen that therebound parameters of elastic-plastic debris are decreasedwith thrown height rising, angle lost coefficient trends to bestable range from 0.56 to 0.75. Dynamic behavior value is instatus of instability accompany breaking rebound. Then, therebound parameters of elastic debris vary with thrown heightin non-linear, and the change trends is closed. When thrownheight is 1.5m, the rebound parameters are in the lowest

value.From figure 11 to figure 14 are curves of rebound

parameters varying with thrown angle. It can be seen that therebound parameters of the elastic-plastic debris vary withthrown angle in non-linear. The change of vertical reboundcoefficient is the key factors affecting rebound parameters andangle lost coefficient. Sometimes angle lost coefficient ishigher than 1. The vertical rebound coefficient, the horizontalrebound coefficient, and the rebound coefficient of elasticdebris vary with thrown angle upward with small changeranges from o.1 to 1.0, but big change ranges in downward.The rebound parameters of elastic appear variation value,

when thrown angle is 15or 70.

IV. CONCLUSION

The rebound parameters of elastic and elastic-plasticdebris in automotive crash varying with thrown condition areanalyzed as followed:

(1) The rebound parameters of elastic-plastic debris varywith thrown velocity in non-linear, but in linear slowly ofelastic.

(2) The rebound parameters of the elastic-plastic debrisdecrease linearly with the increasing of thrown height.Sometimes the vertical rebound coefficient en and the anglelost coefficient fa are higher than 1. Then, the rebound

parameters of elastic debris vary with thrown height innon-linear, and the change trends is closed.

(3) The rebound parameters of elastic-plastic debris varywith thrown angle in non-linear. Sometimes angle lostcoefficient fa is higher than 1. The rebound velocity isconstant about 3.0 ms

-1. The vertical rebound coefficient, the

horizontal rebound coefficient, and the rebound coefficient ofelastic debris vary with thrown angle upward with smallchange ranges, but big change ranges in downward.

ACKNOWLEDGEMENT

This paper is supported by Natural Science Foundation ofHeilongjiang (Grant No. E200943) and National NaturalScience Foundation of China (Grant No. 51108068) and theS&T Plan Projects of Heilongjiang Provincial EducationDepartment (Grant No. 11553025).

REFERENCES

[1] Xu Hong-guo. Automobile Accident Project. BeiJing: ChinaCommunication Press, 2004.

[2] Goldsmith W. The Theory and Physical Behaviour of Colliding Solids.London: Edward Arnold, 1960.

[3] Vincent W. Antone. Estimating the Coefficient of Restitution of Vehicleto Vehicle Bumper Impacts, SAE1998-01-0553, 1998.

[4] Peter M. Burkhard. V, BEV and Coefficient of RestitutionRelationships as Applied to the Interpretation. SAE2001-01-0499, 2001.

[5] Joel W. Cannon. Dependence of a Coefficient of Restitution onGeometry for High Speed Vehicle Collisions. SAE2001-01-0892, 2001.

[6] Lei Zheng-bao, Zhong Zhi-hua, Li Guang-yao, et al. Finite elementmethod for the evaluation of dynamic effects of thin-walled structure inimpacting processes. Chinese Journal of Applied Mechanics. vol. 32, pp.70-77, January. 2000.

[7]

Lin Qing-feng. Dynamics simulations and experimental study of debrisin automotive crashes. Changchun: College of Automotive Engineering,Jilin University, 2006.

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CISME10154-20111223-083926-9941-288