wrex2000 motorcycle crash test paper for wrex2000

Copyright WREX2000

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Seventeen Motorcycle Crash Tests Held at WREX2000 Kelley S. Adamson, P.E., Unified Building Sciences & Engineering, Inc. Peter Alexander, Ph.D., Raymond P. Smith & Associates Ed L. Robinson, Ph.D., Robinson & Associates, LLC Claude I. Burkhead, III, P.E., Advanced Engineering Resources, P.A. John McMannus, P.E., Consulting Engineering Services Gregory C. Anderson, P.E., Scalia Safety Engineering Ralph Aronberg, P.E., Aronberg & Associates Consulting Engineering, Inc. J. Rolly Kinney, ScD., P.E., Kinney Engineering, Inc. David W. Sallmann, P.E., Rudny & Sallmann Engineering Ltd. Gary M. Johnson, Robinson & Associated, LLC Abstract

Organizers staged Seventeen collisions of Kawasaki KZ1000 motorcycles into a rigid, moveable block and mid-sized cars at impact speeds from 10 to 49 mph. The purpose was to characterize motorcycle to barrier and motorcycle to car impacts, crush and trajectories. The motorcycle crash tests will expand the available database.

The rest position, orientation, and attitude of the motorcycle relative to the car were documented and included in the analysis of the data. The motorcycle and vehicles were instrumented with tri-axial accelerometers to assist in the analysis of forces, delta V and post impact trajectories. Some of the tests were video taped with high-speed video and analysis was conducted for comparison and further analysis. This paper characterizes the data collection system, summarizes data collected and the collisions.

The deformation of the cars was dependent on the structure at the impact location. The results of the motorcycle crush indicate a variance in stiffness with respect to impacting object stiffness. Introduction

After the crash tests in 1997 (Crash 97’) several organizers agreed to contact other organizations and combine efforts to have a large accident reconstruction conference. Thanks impart to several individuals, the World Accident Reconstruction Exposition 2000 (WREX2000) was formed. Twenty-one organizations formed the WREX2000 conference. In the 1970's, Severy [1] crash tested seven motorcycles with wire spoke wheels into the sides of automobiles. He published a relationship between the impact speed and the change in motorcycle wheelbase. His motorcycles were all Hondas and ranged in size from 90 to 750 cc and in weight from 200 to 480 lbs. Impact speeds ranged from 20 to 40 mph and all impacts were to the front door or front fender of a 1964 Plymouth 4 door sedan. His results were not dependent on motorcycle weight or size and indicated that the impact speed was proportional to the change in wheelbase and is included in Figure 8. Severy’s motorcycles were nominally upright

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and aligned perpendicular to the side of the car at impact and carried a helmeted dummy.

Mr. Marc Decote, Mr. Paul Schubert and Mr. Mike Sunseri procured the motorcycles through The New Orleans Police department. The 20 donated Kawasaki KX1000 police motorcycles were used at the World Reconstruction Exposition 2000 (WREX2000) held at College Station, Texas September 25-30, 2000. The test area was one of the abandoned concrete runways at the Texas Transportation Institute facility. The cycles had been taken out of service but were generally complete with minimal damage and free movement of both wheels and the head bearing. The test series was developed and directed by Kelley Adamson and executed by a group of participants at the exposition. The authors appreciate the contributions of the following individuals in various aspects of the preparation, execution, and analysis of the tests:

• Mr. Albert G. Fonda, P.E. • Mr. Conrad Dippel • Mr. Joe Montgomery • Officer Mike Winborn • Mr. Marc Decote • Mr. Paul Schubert • Mr. Mike Sunseri • Mr. James Lock • Mr. Philip V. Hight, P.E. • Mr. John R. Smith, P.E.

• Also, the WREX2000 committee.

• The accelerometers and the DynaMax software program were provided by

Instrumented Sensor Technology. Mr. Dan Burk of IST was gracious enough to allow us four units for the tests.

• High-speed video and analysis software were provided by Photosonics & Instrument Marketing Corporation. Contact was Mr. Scott Welle.

The objective of the tests was to evaluate the collision characteristics of a single

model of heavy motorcycle for two stationary targets: a rigid heavy block and an automobile. The motorcycles were intended to be approximately upright and aligned perpendicular to the target surface. An array test matrix was chosen to vary the impact and speed. The impact speed was varied from 10 to 49 mph. The impact into the barrier was close to the center as possible. Impact locations on the car were to the bumper, door, fenders, and wheels.

Impact speed was based on a radar gun measurement of the tow vehicle speed,

the collision dynamics were recorded by an on-board three axis accelerometer system on both vehicles, and the collision consequences determined by inspection and dimensional measurement, and recorded with still and video imagery.

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Seven motorcycles were impacted on the rigid target that was 11,080 lbs. Ten

motorcycles were impacted at various locations on two 1989 Ford Thunderbird vehicles which were donated by TEEX and were complete but had moderate damage to the front bumper. The tests occurred on two days beginning in the morning and ending in late afternoon in full sunlight. The ambient temperature ranged from 42 to 72F. Motorcycles Table 1.

Speed WB

ChangeMC

WeightM/C No. Target Impact Location and Comments mph inches

1 Block Vertical face 42 11.75 606 2 Block Vertical face (M/C leaning left 30 deg at impact) 10 1.125 590 3 Block Vertical face 31 10.25 599 4 Block Vertical face 20 5.25 620 5 Block Vertical face 24 8.25 602 6 Block Vertical face 21 8 616 7 Block Vertical face 35 13 618 8 Car (M) Body between B-post and LR wheel well 46 10.75 615 9 Car (M) Body LR, between wheel well and bumper 39 7.63 620

10 Car (M) Rear bumper, 17 inches left of right end 34 8.25 608 11 Car (M) Right side, between front wheel well and door 25 5.63 611 12 Car (M) Right front wheel 30 3.25 631 13 Car (S) Right door, center 42 6.81 625 14 Car (M) Front bumper, 6 inches right of centerline 30 5.75 633 15 Car (S) No target impact -- 602 16 Car (S) Right front fender between wheel well and bumper 41 7.5 595 17 Car (S) No target impact -- 548 18 Car (S) Front bumper, right of center 45 8.81 610 19 Car (S) Body left rear fender, between wheel well and bumper 49 7.25 611

Targets:

Block Concrete block (See Figure 2) Car 1989 Ford Thunderbirds

(Tests 8-12 and 14, M = Maroon Thunderbird; 13 and 16-19, S = Silver Thunderbird)

Figure 1 shows a typical test motorcycle. Table 1 shows the test number, target, impact location, impact speed, wheelbase change and motorcycle weight. Some cycles had fiberglass fairings as noted in Figure 1, some had crash guard bars, and

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some had parts of saddlebags or a cargo box. The front tires were size 18 65H and were inflated to 28 psig prior to the test. The front wheels were 7 spoke, cast aluminum. Rear tires were inflated to 25 psi. The motorcycles were weighed to an accuracy of 0.1%. The VIN, initial wheelbase, dimensions and weight were recorded on attached data sheets.

Figure 1 Typical Test Motorcycle

The seat was removed and an Instrument System Technology (IST) self-

contained three-axis accelerometer data acquisition package attached to a steel plate and guard, was fastened to the motorcycle frame with U-bolts at the seat position. Figure 2 shows a typical IST installation. The center of the IST box was approximately 20 inches forward of the rear axle and 14 inches above a line between the axles.

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Figure 2 IST Instrumentation Installation

Target Rigid Block

Figure 3 shows the rigid target block. Its dimensions were 120 inches wide, 39 inches high, and 24 inches deep. It was mostly cast concrete with some steel included. The block was weighted and drug with a load cell. Its weight was 11,080 lbs. The load cell reading was used to determine the force to start and maintain movement of the block. The force reading divided by the weigh gave the static and dynamic coefficients of friction. The bottom surface was steel. The coefficient of friction for steel on a similar concrete test surface was measured to be 0.40 dynamic and 0.46 static.

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Figure 3 Concrete Barrier Target Cars

The vehicles were donated by Texas Engineering Extension Service (TEEX). The maroon vehicle was used first and the silver was used second. The Maroon vehicle weight was 3590 lb with 2052 lb on the front and 1538 lb rear. The silver vehicle weight was 3576 lb and 2031 lb on the front and 1545 lb rear. The attached Table 4 shows the nominal specifications for the two 1989 Ford Thunderbirds. All the tires were inflated before the collisions. An IST three-axis data acquisition package was fastened to the steel tunnel between the front seats centered approximately 50 inches forward of the rear axle and 20 inches above the pavement. Motorcycle Delivery System

Figure 4 shows the motorcycles delivery system. After testing different mechanisms to tow the motorcycles, and some adjustments, the tow system was chosen. A fixture welded to a trailer in which a boom protruded that enabled the motorcycle to be held upright from this boom. The boom was comprised of 2 X 2 steel tubing. A wooden 2 X 2 was then inserted into the steel tubing and protruded out approximately 3 feet. Adjustable straps were then attached to the top of the skid bar and

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run vertically to the wooden 2 X 2. The straps were adjusted just enough tension to support the motorcycle upright. The motorcycles were towed to the target and released by fracture of the tow arm during the early phase of the collision. It was found that at speeds below 10 to 15 MPH the motorcycles were unstable. Above that speed the gyroscopic precession helped stabilized the motorcycles.

The motorcycle was towed by an outrigger arm from the left front of a two-axle

flatbed trailer. The outrigger height was sufficient to clear the tops of the car and the target block, and the arm extended about 7 feet beyond to trailer side. A length of wooden 2x2 was inserted into horizontal square steel tube welded to the outrigger arm and it extended beyond the steel outrigger about 20 inches. Two nylon straps looped around the 2x2 and were looped around the fork assembly on the motorcycle to support, guide and tow the cycle. A portion of the motorcycle weight was supported by the outrigger so the forks were extended about 2 inches more than normal. None of the cycles carried rider ballast and none were braked so the fork extension was greater than would be found in most highway collisions.

Figure 4 Motorcycle Tow System

The trailer was towed by a Ford Explorer and the motorcycle was manually stabilized until it was moving somewhat. At impact, the tow strap forces fractured the wooden 2x2 and released the motorcycle. The wooden 2x2 was standard and better

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quality lumber, chemically treated for moisture contact. The impulse contributed by the wooden 2x2 fracture minimal.

The tow arrangement permitted impact locations up to about 8 ½ feet from the

vehicle end, that is, from the middle of the door aft along the left side and from the middle of the door forward along the right side. Two motorcycles had stiff head bearings and were unstable when towed. Data Acquisition System and Data Processing

Four IST systems were used and sequentially installed on the test vehicles. The system contained identical X, Y and Z piezoelectric accelerometers. Output from the accelerometers 12 bit digital signal ranged up to 60 g’s full range deflection, sampled at 3200 per second, and stored in memory each time the trigger level was reached. The trigger levels were set at 3 g’s for 10 ms on the motorcycles and 0.3 seconds of data were stored, beginning 300 ms before the trigger. The car trigger was at ½ to 1 g for 10 ms and 6400 ms were stored. On all vehicles, +X was forward, +Y to the left, and +Z upward. After each collision the IST system memory was copied to a hard drive file and the memory cleared.

The data system had a low pass filter and a typical impact X pulse is shown in Figure 5. Subsequently, the data were passed through an 180Hz. filter and Figure 6 through 10 show X, Y, and Z for a typical impact. The impact acceleration pulse was defined as the interval from the motorcycle X-axis accelerometer record to be from an initial 1 g level of the final filtered signal to 180Hz. The pulse integrals and pulse duration were taken for that interval. The Delta V was computed from the pulse integral using the DynaMax software. It is possible to import the converted text data files into any spread sheet program and compete the same analysis.

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Figure 5 IST Data Plot - Non-Filtered

Figure 6 IST Data Plot - Filtered

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Impact Speed

The tow vehicle speed was measured with a hand-held Stalker model radar gun in the right front seat of the tow vehicle and the impact speed visually judged by the operator. High-speed video was used to confirm impact speeds. Two tests were compared which indicates an accuracy of +/- 1.6 mph. The larger error was found on the slower impact due to the angle of the gun to target relative to the speed. Position Measurements and Motorcycle & Vehicle Weights

Rest positions were measured relative to the original position of the target with a steel tape, plumb bob, and chalk marks. Vehicle dimensions were measured by steel tape. The 95% confidence uncertainty for dimensions is +/- ½ inch.

Vehicle Weights and Balance

Vehicle weights were measured with four electronic scales with 99.9% accuracy. However, the flatness of the surface between the scales was not measured. As a result, the lateral load balance values on the cars may not accurately represent the mass center location. Test Procedure

The motorcycles, barrier and vehicles were prepared for the tests. The motorcycle were weighed and measured by the team of Ralph Aronberg, Gregory Anderson, Claude Burkhead and Albert Fonda. The target was moved to position the desired target impact area in the towpath on an unmarked pavement area and the target initial position was marked on the pavement. The motorcycle was strapped to the tow bar and towed nominally along a straight path to the impact area. The motorcycle path was perpendicular to the face to be struck. Multiple video and still cameras recorded the collision from the sides and rear. The motorcycle preparation and delivery team consisted of John McMannus, Claude Burkhead and James Lock. Some other unidentified participants volunteered and their participation is greatly appreciated.

Immediately after impact, the overall scene was photographed. Then the positions of the target and motorcycle were measured by one team and a second team measured the deformation of the vehicles. The rest positions were measured relative to the original target position. The collision accelerometer pulse was recorded by the onboard IST system. The accelerometer data was down loaded to a computer hard drive.

The scene was cleared of all debris, motorcycle was removed and the block was

repositioned and marked for the next test. The next motorcycle was prepared by the team of Peter Alexander and Rolly Kinney. The motorcycle was moved to the tow start

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point located several hundred feet from the target.

Crash Tests After each test, the barrier and motorcycle measurements were made by the

team consisting of Ralph Aronberg, David Sallmann, Claude Burkhead, Gregory Anderson and Albert Fonda. Data extraction was performed by Peter Alexander and Rolly Kinney. Video and photography were preformed by Kelley Adamson and Claude Burkhead.

Tests 1 thru 7 were of the motorcycles impacting the concrete barrier at 90 degrees. The barrier displacement was recorded and is indicated in the drawings of each test. The motorcycles all rebounded backwards and in general upright with exception for Test 2. In Test 2, the motorcycle impact speed was slow and at impact the motorcycle was leaning approximately 30 degrees left. As a results, the motorcycle fell over more quickly. It was noted in the high-speed video footage that the kickstand and center stand would drop down. In Test 5 the motorcycle came to rest on its kickstand. Impact and rest position drawings were provided by Mr. Ralph Aronberg and Mr. Kelley Adamson. The impacts to the barrier are shown in subfolder Impact Drawings of the CD. In Tests 8 through 19, with the exception of Tests 15 and 17, the motorcycle path was perpendicular to the contact face. The vehicles were impacted into different locations on different sides. The impacts to the vehicle are shown in subfolder Impact Drawings of the CD. The drawings were provided by Mr. Ralph Aronberg and Mr. Kelley Adamson. After each test, the vehicle damage was measured and recorded. The vehicle damage measurements and drawings were provided by Dr. Ed Robinson & Mr. Gary Johnson. The raw measurements are attached to this report. The drawings can be found in the subfolder MC Crash Test Vehicle Diagrams. Test Results

Table 1 shows the test conditions and results. Figure 7 shows the relationship between impact speed and the change in wheelbase and rim radius change. Figure 8 shows the wheelbase change for the barrier and vehicle for the impact speed. Severy’s data is also included.

High-speed video was recorded and analyzed for Test 3 and 4. The results of the

analysis are shown in Table 2. The Phantom, demo version, software was used for the analysis. The program requires an initial scaling of the image from which further analysis is completed. Distances and velocities can be determined from the scaling and frame rate.

The high-speed video allowed the study of the motion and crushing of the

motorcycle. It was noted that the front suspension compressed fully before deformation

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of the front axle began. The front wheel also would climb the barrier slightly. After the collision, the front wheel was locked. Table 2 Radar Speed (MPH)

Video Speed (MPH)

Dynamic Crush (inches)

Static Crush (inches)

Time to Zero Velocity (ms)

Post Impact Rebound Speed (MPH)

31 31.1 15 10.25 40 5.2 20 21.6 7.9 5.7 55 6.1

Figure 7 Discussion of Results

The acceleration data recorded in the barrier tests was used to determine the collision impulse time and the change in speed (Delta V). This data is summarized in Table 3 including the barrier CG displacement.

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Table 3

M/C No.

Target Impact Speed

(m.p.h.) Collision Impulse

Duration (sec.) Delta-V (mph)

Barrier CG Displacement

(ft)

1 Concrete

Block 42 0.054 47.7* 0.83

2 Concrete

Block 10 0.125 15.5 0.0

3 Concrete

Block 31 0.073 36.3* 0.23

4 Concrete

Block 21.6 No data 27.7** 0.11

5 Concrete

Block 24 0.065 30.6* 0.08

6 Concrete

Block 21 0.080 24.7 0.46

7 Concrete

Block 35 0.063 38.5* 0.42

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• * The accelerometer briefly saturated above the 60 g’s limit. The values shown were determined from the integration of the post impact pulse and the addition of the radar gun impact speed.

• ** Pre & post impact and rebound speed was determined through high-speed video analysis.

The wheelbase change, Figure 8, was approximately linear but stiffer than the relationship shown by Severy. In figure 9, the relationship of the wheelbase change (stiffness) can be seen for Delta V speed into the barrier and vehicles. It must be noted that Severy measured the impact speed of the motorcycle and did not take into account Delta V speeds.

The coefficient of restitution values was determined through the Delta V derived

for each tests. To determine the rebound speed of the motorcycle, time integration of the acceleration pulse or high-speed analysis was used. Figure 10 shows the difference in Restitution between the barrier and the vehicle impact for Delta V. Certain tests restitution values were not included in Figure 10 due to vehicle rotation.

The correlation between the motorcycle wheelbase change and the impact speed

measured for the KZ1000 motorcycles impacting both the barriers and the 1989 Ford Thunderbirds is shown in Figure 8. The scatter of the points indicates the variability of the crush for the motorcycle impacting varying objects. The scatter of the impact with the barrier shows approximately a +/- 5 mph variance and the vehicle shows approximately a +/- 9 mph variance.

The accuracy of the restitution values is subject to the accuracy of the Delta V

values. The Delta V values were determined through the integration of the accelerometer data except as noted. The motorcycles were not instrumented with rate gyros and therefore the pitch effect on the X-axis was not able to be determined. The barriers were not instrumented with accelerometers so the exact displacement (kinetic) energy is not known. Through the comparison of the accelerometer data and the high-speed analysis, the effect was small. Also a comparison of the motorcycle and vehicle impact was compared and the correlation was consistent.

Other affects that could cause the variance;

• The point of impact was aligned with a spoke or between the spokes, • The tire remained inflated (e.g., after on of the higher speed impacts, it was

noted that the tire remained inflated and the wheelbase was not shortened as much)

• The cast aluminum wheel rim fractured • Energy dissipation of the struck objects and differences in post impact movement

(e.g., post impact movement of the barrier was not consistent with impact

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speeds) • At the higher speeds, the wheelbase reduction was effected by the reduction of

the rim diameter. The maximum wheelbase reduction was limited by the front wheel rim contact with the engine block.

Observation of the rim deformation and fracture indicate that the rim bending or

fractured with the barrier at the direct contact point. In the tests with the vehicles, the rim bending or fracture indicated fracture with the engine block.

Figure 8

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Figure 9

Figure 10

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DATA All written and computer data, diagrams, images, video and report is copyrighted by WREX2000. No part of the written data sheets, computer data, diagrams and report may by reproduction in any form, in an electronic retrieval system or otherwise, without the prior written permission of the WREX2000 organizers. The raw data was recorded from the IST instrumentation and downloaded to a hard drive. The data was then analyzed with the DynaMax software. The data was also converted to text format. Survey of the scene and vehicle were provided by the AIRP group in the form of data sheets and AutoCAD drawing files. The data is contained on the CD under IST DATA motorcycle-barrier and IST DATA motorcycle-vehicle subfolder. The IST program creates a filename.udf file. The udf file has been converted into text file with each test subfolder. The data consists of four columns of time, X, Y and Z-axis acceleration pulse. Any text program and/or spreadsheet program can be used to open the file. All available photographs and recorded data is included on the CD. Recorded testing data was converted to jpg image format. Diagrams of the DynaMax analysis are included in the subfolder Accel Diagrams. Acceleration diagrams were provided by Dr. Peter Alexander. Record data during testing are included in the subfolder MC Crash Data Sheets. Conclusions The Ford Thunderbird crush and Kawasaki KZ1000 wheelbase reduction presented in this paper may help in motorcycle accident reconstructions. The 1990’s model Kawasaki KZ 1000 motorcycles are stiffer than that of the 1970’s Honda motorcycles tested by Severy. Motorcycle wheelbase reduction was dependent upon the stiffness/heavier object struck. In these tests, the same model motorcycle was used and yet the wheelbase reduction varied more than that of the tests conducted by Severy. This could be due to varying impact conditions, impacted object stiffness and/or variability of the mode of failure of the motorcycle components and structure. References 1 Severy, Brink, and Blaisdell, Motorcycle Collision Experiments, 14th Stapp Car

Crash Conference, 1970, SAE 700897

wrex2000 motorcycle crash test paper for wrex2000

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