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85  After performing full-scale crash tests, it was necessary to validate the 1100C vehicle model used in the Chapter 2 computer simulations. This chapter details the efforts and methods used to validate the 1100C FE vehicle model. Development of Bridge Rail Models FE models of the two bridge rail systems crash tested in Chapter 3 were developed for impact simulations. The rails, posts, base plates, angle brackets, and connections were all representative of the physical installations. Figures 4.1 and 4.2 show the two computer bridge rail models. Initial simulations were performed with the small car vehicle model impacting the two bridge rail systems. The impact conditions were representative of the crash-test impact conditions. For the deck-mounted system, the small car vehicle model impacted the system at a speed of 63.2 mph and an angle of 24.2 degrees. The impact location was 3.4 ft. upstream of the centerline of post 3. For the curb-mounted system, the small car vehicle model impacted the system at a speed of 60.9 mph and an angle of 24.9 degrees. The impact location was 3.4 ft. upstream of the centerline of post 3. Figures 4.3 and 4.4 show the small car model during impact with the deck- mounted system and curb-mounted system, respectively. The behavior of the simulation vehicle was not comparable to the crash tests because the model did not allow for the front driver-side wheel to release during impact with the post. In both crash tests, the front driver-side wheel impacted the post and released. It was therefore necessary to modify the vehicle model to allow for the wheel to release during impact with the post. 1100C Vehicle Model Modifications The primary difference between the full-scale crash tests and the initial computer simulations was the release of the front left tire as it impacted the bridge rail post. Figure 4.5 shows the vehicle and front driver-side wheel after impacting the deck-mounted system. Figure 4.6 shows the vehicle and front driver-side wheel after impacting the curb-mounted system. Five main joints connect the wheel to the rest of the vehicle: two ball or spherical joints, two revolute joints, and the fifth joint uses bolted connections. As seen in the previous figures, most of these joints failed in both crash tests. For the fifth joint, the material around the bolted con- nections yielded and failed during both crash tests. Figures 4.7 and 4.8 show the vehicle model with the different joints. C H A P T E R 4 Validation of the Small Car Vehicle Model
86 Evaluation of Bridge Rail Systems to Confirm AASHTO MASH Compliance Figure 4.1. Bridge rail LS-DYNA model without curb. Figure 4.2. Bridge rail LS-DYNA model with curb. Figure 4.3. 1100C simulation vehicle impacting deck-mounted system. Figure 4.4. 1100C simulation vehicle impacting curb-mounted system.
Validation of the Small Car Vehicle Model 87  Figure 4.5. Vehicle and wheel damage after impact with deck-mounted system.
88 Evaluation of Bridge Rail Systems to Confirm AASHTO MASH Compliance Figure 4.6. Vehicle and wheel damage after impact with curb-mounted system. After reviewing the crash-test videos and photos, it was determined that each of the five joints failed in the deck-mounted crash test or in the curb-mounted crash test. Therefore, failure criteria need to be defined for each of these joints. The joint failure limiting forces were determined through iterative simulations using different joint failure values and selecting the one that caused the sus- pension to exhibit a failure pattern similar to the patterns observed in the tests. Figure 4.9 shows an example of the longitudinal forces in the wheel lower spherical joint. A peak force value of 200,000 N is observed at 0.1 s. A failure value was defined below this maximum 200,000 N value.
Validation of the Small Car Vehicle Model 89  0 0.2 0.4 0.6 0.8 Figure 4.9. Longitudinal forces in wheel lower spherical joint. Figure 4.7. Wheel joints. Figure 4.8. Lower control arm joints.
90 Evaluation of Bridge Rail Systems to Confirm AASHTO MASH Compliance This same procedure was applied for each joint. To allow failure of the connection to the shock absorber, plastic strain-based failure was added to allow failure of the material surrounding the bolted connections. Table 4.1 summarizes the failure criteria values for each joint. No other modifications were made to the 1100C vehicle model. The next sections summarize the validation and verification procedures for the two simulations incorporating this updated vehicle model. Validation of Deck-Mounted System A computer simulation was performed with the updated 1100C vehicle model impacting the deck-mounted bridge rail system. The impact conditions replicated the impact conditions from the full-scale crash test. Figures 4.10 and 4.11 show sequential comparisons between the computer simulation and full-scale crash test. The research team used the procedures developed in Ray et al. (13) to quantify and qualify the validity of the updated 1100C model. The procedures consist of three parts: 1. Solution verification 2. Quantitative evaluation 3. Validation of crash-specific phenomena The results for each part are provided here. Part IâSolution Verification The research team performed global checks of the analysis to verify that the numerical solution was stable and was producing physical results. Table 4.2 shows the global checks performed and the resulting evaluation. The numerical solution meets all the recommended global energy criteria and appears to achieve good numerical stability. Part IIâQuantitative Evaluation The RSVVP program developed in NCHRP 22-24 was used to compute the Sprague-Geers metrics and analysis-of-variance (ANOVA) metrics using time-history data from the full-scale crash test and simulation. Table 4.3 shows the results of the evaluation for the individual channels. Figures 4.12 through 4.17 show the time histories for each pair of data used to compute the metrics. Based on the Sprague-Geer metrics, x-acceleration and yaw rate from the numerical analysis were in good agreement with the crash test. The ANOVA metrics indicated the numerical analysis was in good agreement with the crash tests except for the yaw rate. Joint Failure Type Failure Value Wheel Lower Spherical Joint Force-Based 100,000 N Wheel Side Spherical Joint Force-Based 60,000 N Wheel to Shock Absorber Joint Strain-Based in Surrounding Material 0.2 (plastic strain) Lower Control Arm Left Joint Force-Based 60,000 N Lower Control Arm Right Joint Force-Based 60,000 N Table 4.1. Failure criteria for 1100C vehicle model wheel and suspension joints.
Validation of the Small Car Vehicle Model 91  Time 0.000 s 0.050 s 0.100 s 0.150 s Full-Scale Crash Test Computer Simulation Figure 4.10. Sequential comparison of full-scale crash test and simulation with deck-mounted system (gut view). (continued on next page)
92 Evaluation of Bridge Rail Systems to Confirm AASHTO MASH Compliance Full-Scale Crash Test Computer SimulationTime 0.200 s 0.250 s 0.300 s 0.350 s Figure 4.10. (Continued).
Full-Scale Crash TestTime 0.000 s 0.050 s 0.100 s 0.150 s Computer Simulation Figure 4.11. Sequential comparison of full-scale crash test and simulation with deck-mounted system (overhead view). (continued on next page)
94 Evaluation of Bridge Rail Systems to Confirm AASHTO MASH Compliance Full-Scale Crash TestTime 0.200 s 0.250 s 0.300 s 0.350 s Computer Simulation Figure 4.11. (Continued).
Validation of the Small Car Vehicle Model 95  Verification Evaluation Criteria Change (%) Pass? Total energy of the analysis solution (i.e., kinetic, potential, contact, etc.) must not vary more than 10% from the beginning of the run to the end of the run. 0.2 YES Hourglass energy of the analysis solution at the end of the run is less than 5% of the total initial energy at the beginning of the run. 4.2 YES Hourglass energy of the analysis solution at the end of the run is less than 10% of the total internal energy at the end of the run. 8.9 YES The part/material with the highest amount of hourglass energy at the end of the run is less than 10% of the total internal energy of the part/material at the end of the run. 2.3 YES Mass added to the total model is less than 5% of the total model mass at the beginning of the run. 0.4 YES The part/material with the most mass added had less than 10% of its initial mass added. 7.7 YES The moving parts/materials in the model have less than 5% of mass added to the initial moving mass of the model. 0.3 YES There are no shooting nodes in the solution? No YES There are no solid elements with negative volumes? No YES Table 4.2. Summary of global checks for deck-mounted system. Evaluation Criteria Time Interval (0 s; 0.8 s) O Sprague-Geers Metrics List all the data channels being compared. Calculate the M and P metrics using RSVVP and enter the results. Values less than or equal to 40 are acceptable. RSVVP Curve Preprocessing Options M P Pass? Filter Option Sync. Option Shift Drift True Curve Test Curve True Curve Test Curve X Acceleration CFC_180 N N N N N 7.9 30.4 Y Y Acceleration CFC_180 N N N N N 9.3 40.8 N Z Acceleration CFC_180 N N N N N 38.2 49.4 N Roll Rate CFC_180 N N N N N 28.7 51.7 N Pitch Rate CFC_180 N N N N N 77.1 49 N Yaw Rate CFC_180 N N N N N 19.9 12.6 Y P ANOVA Metrics List all the data channels being compared. Calculate the ANOVA metrics using RSVVP and enter the results. Both of the following criteria must be met: ⢠The mean residual error must be less than 5% of the peak acceleration (e 0.05 aPeak) ⢠The standard deviation of the residuals must be less than 35% of the peak acceleration ( 0.35 aPeak) M ea n R es id ua l St an da rd D ev ia tio n of R es id ua ls Pass? X Acceleration/Peak 0.01 0.12 Y Y Acceleration/Peak 0.01 0.15 Y Z Acceleration/Peak 0.01 0.24 Y Roll Rate 0.02 0.25 Y Pitch Rate 0.01 0.22 Y Yaw Rate 0.08 0.08 N Table 4.3. Roadside safety validation metricsâsingle channel.
96 Evaluation of Bridge Rail Systems to Confirm AASHTO MASH Compliance True and Test Curves (ChannelX loc) True and Test Curves Velocity (ChannelX) Figure 4.12. X-channel time-history data. True and Test Curves (ChannelY loc) True and Test Curves Velocity (ChannelY) Figure 4.13. Y-channel time-history data.
Validation of the Small Car Vehicle Model 97  True and Test Curves (ChannelZ loc) True and Test Curves Velocity (ChannelZ) Figure 4.14. Z-channel time-history data. True and Test Curves (Channelroll Rate loc) True and Test Curves Velocity (Channelroll Rate) Figure 4.15. X-channel roll time-history data.
98 Evaluation of Bridge Rail Systems to Confirm AASHTO MASH Compliance True and Test Curves (Channelpitch Rate loc) True and Test Curves Velocity (Channelpitch Rate) Figure 4.16. Y-channel pitch time-history data. True and Test Curves (Channelyaw Rate loc) True and Test Curves Velocity (Channelyaw Rate) Figure 4.17. Z-channel yaw time-history data.
Validation of the Small Car Vehicle Model 99  Since the metrics computed for the single channels did not all satisfy the acceptance criteria, the multichannel option in RSVVP was used to calculate the weighted Sprague-Geers and ANOVA metrics for the six channels of data. Table 4.4 shows the results from RSVVP for the multichannel option using the Area II method. The weighted metrics in RSVVP using the Area II method in the multichannel mode all satisfy the acceptance criteria. Therefore, the time-history comparison can be considered acceptable. Part IIIâValidation of Crash-Specific Phenomena The phenomena observed in both the crash tests and the numerical solution were com- pared. Table 4.5 shows a comparison of phenomena related to structural adequacy. Table 4.6 shows a comparison of phenomena related to occupant risk. Table 4.7 shows a comparison of phenomena related to vehicle trajectory. The comparison between all the structural adequacy phenomena was acceptable. Evaluation Criteria (Time Interval [0 s; 0.8 s]) Channels (Select Which Were Used) X Acceleration Y Acceleration Z Acceleration Roll Rate Pitch Rate Yaw Rate Multichannel Weights Area II Method X Channel: 0.214 Y Channel: 0.272 Z Channel: 0.014 Yaw Channel: 0.36 Roll Channel: 0.108 Pitch Channel: 0.030 O Sprague-Geer Metrics Values less than or equal to 40 are acceptable. M P Pass? 17.4 29.9 Y P ANOVA Metrics Both of the following criteria must be met: ⢠The mean residual error must be less than 5% of the peak acceleration (e 0.05 · aPeak) ⢠The standard deviation of the residuals must be less than 35% of the peak acceleration (s 0.35 · aPeak) M ea n R es id ua l St an da rd D ev ia tio n of R es id ua ls Pass? 0.03 0.13 Y Table 4.4. Roadside safety validation metricsâmultichannel. Evaluation Criteria Known Result Analysis Result Difference Relative/ Absolute Agree? St ru ct ur al A de qu ac y A A1 Test article should contain and redirect the vehicle; the vehicle should not penetrate, underride, or override the installation although controlled lateral deflection of the test article is acceptable. (Answer Yes or No) Yes Yes YES A2 Maximum dynamic deflection: ⢠Relative difference is less than 20% or ⢠Absolute difference is less than 0.15 m 0.0 0.0 0.0 YES A3 Length of vehicle-barrier contact: ⢠Relative difference is less than 20% or ⢠Absolute difference is less than 2 m 4.3 m 3.2 m 25% 1.1 m YES A4 Number of broken or significantly bent posts is less than 20%. 0 0 0 YES A5 Did the rail element rupture or tear? (Answer Yes or No) No No YES A6 Were there failures of connector elements? (Answer Yes or No) No No YES A7 Was there significant snagging between the vehicle wheels and barrier elements? (Answer Yes or No) Yes Yes YES A8 Was there significant snagging between vehicle body components and barrier elements? (Answer Yes or No) Yes Yes YES Table 4.5. Structural adequacy phenomena.
100 Evaluation of Bridge Rail Systems to Confirm AASHTO MASH Compliance Evaluation Criteria Known Result Analysis Result Difference Relative/ Absolute Agree? O cc up an t R is k D Detached elements, fragments, or other debris from the test article should not penetrate or show potential for penetrating the occupant compartment, or present an undue hazard to other traffic, pedestrians, or personnel in a work zone. (Answer Yes or No) Pass Pass YES F F1 The vehicle should remain upright during and after the collision although moderate roll; pitching and yawing are acceptable. (Answer Yes or No) Pass Pass YES F2 Maximum roll of the vehicle: ⢠Relative difference is less than 20% or ⢠Absolute difference is less than 5 degrees â16.6 â9.9 40.4% 6.7 deg NO F3 Maximum pitch of the vehicle is: ⢠Relative difference is less than 20% or ⢠Absolute difference is less than 5 degrees â4.8 â6.3 31.3% 1.5 deg YES F4 Maximum yaw of the vehicle is: ⢠Relative difference is less than 20% or ⢠Absolute difference is less than 5 degrees 48 29.9 37.7% 18.1 deg NO L L1 OIV: ⢠Relative difference is less than 20% or ⢠Absolute difference is less than 2 m/s ⢠Longitudinal OIV (m/s) 7.8 8.5 9.0 % 0.7 m/s YES ⢠Lateral OIV (m/s) â9.6 â8.5 11.5% 1.1 m/s YES ⢠THIV (theoretical head impact velocity; m/s) 12.4 11.5 7.3% 0.9 m/s YES L2 Occupant accelerations: ⢠Relative difference is less than 20% or ⢠Absolute difference is less than 4 gâs ⢠Longitudinal RDA â11.9 â7.0 33.6% 4.9 gâs NO ⢠Lateral RDA 14.4 9.6 33.3% 4.8 gâs NO ⢠PHD (post-impact head deceleration) 18.6 9.6 48.4% 9.0 gâs NO ⢠ASI (acceleration severity index) 2.27 2.21 2.6% 0.06 YES Table 4.6. Occupant risk phenomena. Evaluation Criteria Known Result Analysis Result Difference Relative/ Absolute Agree? V eh ic le T ra je ct or y M M1 The exit angle from the test article preferable should be less than 60% of test impact angle, measured at the time of vehicle loss of contact with test device. Yes 8.35 deg Yes 11.9 deg YES M2 Exit angle at loss of contact: ⢠Relative difference is less than 20% or ⢠Absolute difference is less than 5 degrees 8.35 deg 11.9 deg 42.5% 3.55 deg YES M3 Exit velocity at loss of contact: ⢠Relative difference is less than 20% or ⢠Absolute difference is less than 10 kmh 75.8 kmh 66.6 kmh 12.1% 9.2 kmh YES M4 One or more vehicle tires failed or de-beaded during the collision event. (Answer Yes or No) Yes Yes YES Table 4.7. Vehicle trajectory phenomena.
Validation of the Small Car Vehicle Model 101  The maximum roll and yaw angles were both less in the computer simulation than in the full- scale crash test. One factor that may have influenced the computer simulation roll and yaw angles was that the simulation vehicle rode over the released tire as it was exiting the system. This likely had a small effect on the vehicle angular values. In addition, the crash-test roll angle was relatively small in comparison to the MASH-2016 limit. Thus, it was not critical to achieve good correlation in the computer simulation. The occupant risk longitudinal and lateral OIV values were both in good comparison between the full-scale crash test and computer simulation. The longitudinal and lateral RDA values were both lower in the computer simulation than in the full-scale crash test. The absolute difference of about 5 gâs for both was still close to the 4 g criterion. Furthermore, the RDA values were below the MASH-2016 limit and below the MASH-2016 preferred limit. Thus, these values are not as critical because they are not likely to cause a failed MASH-2016 test or simulation. Overall, the computer simulation appears to agree with the full-scale crash tests, with the excep- tions noted. The key portion of the impact event is the impact with the first bridge rail post, for which the simulation appears to achieve good correlation with the full-scale crash test. The vehicle trajectory phenomena for the full-scale crash test and computer simulations were compared. All criteria were considered acceptable, and the numerical analysis was in good agreement with the crash test. In particular, the Criterion M4 comparison showed the front driver-side tire failing in both the full-scale crash tests and the computer simulation. Overall, the simulation reasonably agrees with the full-scale crash test besides the few excep- tions noted. Thus, the simulation can be considered validated. Validation of Curb-Mounted System A computer simulation was performed with the updated 1100C vehicle model impacting the curb-mounted bridge rail system. The impact conditions replicated the impact conditions from the full-scale crash test. Figures 4.18 and 4.19 show sequential comparisons between the computer simulation and full-scale crash test. The research team used the procedures developed in Ray et al. (13) to quantify and qualify the validity of the updated 1100C model. The procedures consist of three parts: 1. Solution verification 2. Quantitative evaluation 3. Validation of crash-specific phenomena The results for each part are provided here. Part IâSolution Verification The research team performed global checks of the analysis to verify that the numerical solu- tion was stable and was producing physical results. Table 4.8 shows some of the global checks performed and the resulting evaluation. The numerical solution meets all the recommended global energy criteria and appears to achieve good numerical stability. Part IIâQuantitative Evaluation Again, the RSVVP program was used to compute the Sprague-Geers and ANOVA metrics using time-history data from the full-scale crash test and simulation. Table 4.9 shows the results of the evaluation for the individual channels. Figures 4.20 through 4.25 show the time histories for each pair of data used to compute the metrics.
102 Evaluation of Bridge Rail Systems to Confirm AASHTO MASH Compliance Time Full-Scale Crash Test Computer Simulation 0.000 s 0.050 s 0.100 s 0.150 s Figure 4.18. Sequential comparison of full-scale crash test and simulation with curb-mounted system (gut view).
Validation of the Small Car Vehicle Model 103  Time Full-Scale Crash Test Computer Simulation 0.200 s 0.250 s 0.300 s 0.350 s Figure 4.18. (Continued).
104 Evaluation of Bridge Rail Systems to Confirm AASHTO MASH Compliance Time Full-Scale Crash Test Computer Simulation 0.000 s 0.050 s 0.100 s 0.150 s Figure 4.19. Sequential comparison of full-scale crash test and simulation with curb-mounted system (overhead view).
Validation of the Small Car Vehicle Model 105  Time Full-Scale Crash Test Computer Simulation 0.200 s 0.250 s 0.300 s 0.350 s Figure 4.19. (Continued).
106 Evaluation of Bridge Rail Systems to Confirm AASHTO MASH Compliance Verification Evaluation Criteria Change (%) Pass? Total energy of the analysis solution (i.e., kinetic, potential, contact, etc.) must not vary more than 10% from the beginning of the run to the end of the run. 0.5 YES Hourglass energy of the analysis solution at the end of the run is less than 5% of the total initial energy at the beginning of the run. 4.5 YES Hourglass energy of the analysis solution at the end of the run is less than 10% of the total internal energy at the end of the run. 9.0 YES The part/material with the highest amount of hourglass energy at the end of the run is less than 10% of the total internal energy of the part/material at the end of the run. 2.7 YES Mass added to the total model is less than 5% of the total model mass at the beginning of the run. 0.3 YES The part/material with the most mass added had less than 10% of its initial mass added. 7.7 YES The moving parts/materials in the model have less than 5% of mass added to the initial moving mass of the model. 0.3 YES There are no shooting nodes in the solution? No YES There are no solid elements with negative volumes? No YES Table 4.8. Summary of global checks for curb-mounted system. Evaluation Criteria Time interval (0 s; 0.8 s) O Sprague-Geers Metrics List all the data channels being compared. Calculate the M and P metrics using RSVVP and enter the results. Values less than or equal to 40 are acceptable. RSVVP Curve Preprocessing Options M P Pass?Filter Option Sync. Option Shift Drift True Curve Test Curve True Curve Test Curve X Acceleration CFC_180 N N N N N 2.5 26.8 Y Y Acceleration CFC_180 N N N N N 21.9 34.7 Y Z Acceleration CFC_180 N N N N N 8 44.5 N Roll Rate CFC_180 N N N N N 46.9 43.6 N Pitch Rate CFC_180 N N N N N 6.8 44.4 N Yaw Rate CFC_180 N N N N N 21.6 19.5 Y P ANOVA Metrics List all the data channels being compared. Calculate the ANOVA metrics using RSVVP and enter the results. Both of the following criteria must be met: ⢠The mean residual error must be less than 5% of the peak acceleration (e 0.05 · aPeak) ⢠The standard deviation of the residuals must be less than 35% of the peak acceleration ( 0.35 · aPeak) M ea n R es id ua l St an da rd D ev ia tio n of R es id ua ls Pass? X Acceleration/Peak 0.01 0.16 Y Y Acceleration/Peak 0.01 0.14 Y Z Acceleration/Peak 0.01 0.18 Y Roll Rate 0.01 0.17 Y Pitch Rate 0.01 0.18 Y Yaw Rate 0.04 0.12 Y Table 4.9. Roadside safety validation metricsâsingle channel.
Validation of the Small Car Vehicle Model 107  Figure 4.20. X-channel time-history data. True and Test Curves (ChannelX loc) True and Test Curves Velocity (ChannelX) Figure 4.21. Y-channel time-history data. True and Test Curves (ChannelY loc) True and Test Curves Velocity (ChannelY)
108 Evaluation of Bridge Rail Systems to Confirm AASHTO MASH Compliance Figure 4.22. Z-channel time-history data. True and Test Curves (ChannelZ loc) True and Test Curves Velocity (ChannelZ) Figure 4.23. X-channel roll time-history data. True and Test Curves (Channelroll Rate loc) True and Test Curves Velocity (Channelroll Rate)
Validation of the Small Car Vehicle Model 109  Figure 4.24. Y-channel pitch time-history data. True and Test Curves (Channelpitch Rate loc) True and Test Curves Velocity (Channelpitch Rate) Figure 4.25. Z-channel yaw time-history data. True and Test Curves (Channelyaw Rate loc) True and Test Curves Velocity (Channelyaw Rate)
110 Evaluation of Bridge Rail Systems to Confirm AASHTO MASH Compliance Based on the Sprague-Geer metrics, the x-acceleration, y-acceleration, and yaw rate from the numerical analysis were in good agreement with the crash test. The ANOVA metrics indicated that the numerical analysis was in good agreement with the crash test for all channels. Since the metrics computed for the single channels did not all satisfy the acceptance criteria, the multichannel option in RSVVP was used to calculate the weighted Sprague-Geers and ANOVA metrics for the six channels of data. Table 4.10 shows the results from RSVVP for the multichannel option using the Area II method. The weighted metrics in RSVVP using the Area II method in the multichannel mode all satisfy the acceptance criteria. Therefore, the time-history comparison can be considered acceptable. Part IIIâValidation of Crash-Specific Phenomena The phenomena observed in the crash tests and the numerical solution were compared. Table 4.11 shows a comparison of phenomena related to structural adequacy. Table 4.12 shows a comparison of phenomena related to occupant risk. Table 4.13 shows a comparison of phenomena related to vehicle trajectory. The comparison between all the structural adequacy phenomena was acceptable. A comparison of the simulation and full-scale crash test occupant risk phenomena resulted in good comparisons except the maximum yaw angle. The yaw angle in the computer simulation was less than the full-scale crash test by about 10 degrees. The yaw of the vehicle is not a critical criterion in terms of occupant risk and is relatively low overall. Thus, the research team concluded that the computer simulation achieved good correlation with the occupant risk phenomena. The vehicle trajectory phenomena for the full-scale crash test and computer simulations were compared. All criteria were considered acceptable, and the numerical analysis was in good agree- ment with the crash test. In particular, the Criterion M4 comparison showed the front driver- side tire failing in both the full-scale crash tests and computer simulation. Overall, the simulation reasonably agrees with the full-scale crash test besides the few excep- tions noted. Thus, the simulation can be considered validated. Table 4.10. Roadside safety validation metricsâmultichannel. Evaluation Criteria (time interval [0 s; 0.8 s]) Channels (Select Which Were Used) X Acceleration Y Acceleration Z Acceleration Roll Rate Pitch Rate Yaw Rate Multichannel Weights Area II Method X Channel: 0.346 Y Channel: 0.139 Z Channel: 0.014 Yaw Channel: 0.403 Roll Channel: 0.047 Pitch Channel: 0.051 O Sprague-Geer Metrics Values less than or equal to 40 are acceptable. M P Pass? 15 27 Y P ANOVA Metrics Both of the following criteria must be met: ⢠The mean residual error must be less than 5% of the peak acceleration (e 0.05 · aPeak) ⢠The standard deviation of the residuals must be less than 35% of the peak acceleration ( 0.35 · aPeak) M ea n R es id ua l St an da rd D ev ia tio n of R es id ua ls Pass? 0.02 0.14 Y
Table 4.11. Structural adequacy phenomena. Evaluation Criteria Known Result Analysis Result Difference Relative/ Absolute Agree? St ru ct ur al A de qu ac y A A1 Test article should contain and redirect the vehicle; the vehicle should not penetrate, underride, or override the installation although controlled lateral deflection of the test article is acceptable. (Answer Yes or No) Yes Yes YES A2 Maximum dynamic deflection: ⢠Relative difference is less than 20% or ⢠Absolute difference is less than 0.15 m 0.0 0.0 0.0 YES A3 Length of vehicle-barrier contact: ⢠Relative difference is less than 20% or ⢠Absolute difference is less than 2 m 4.8 m 3.8 m 20.8% 1.0 m YES A4 Number of broken or significantly bent posts is less than 20%. 0 0 0 YES A5 Did the rail element rupture or tear? (Answer Yes or No) No No YES A6 Were there failures of connector elements? (Answer Yes or No) No No YES A7 Was there significant snagging between the vehicle wheels and barrier elements? (Answer Yes or No) Yes Yes YES A8 Was there significant snagging between vehicle body components and barrier elements? (Answer Yes or No) Yes Yes YES Table 4.12. Occupant risk phenomena. Evaluation Criteria Known Result Analysis Result Difference Relative/ Absolute Agree? O cc up an t R is k D Detached elements, fragments, or other debris from the test article should not penetrate or show potential for penetrating the occupant compartment, or present an undue hazard to other traffic, pedestrians, or personnel in a work zone. (Answer Yes or No) Pass Pass YES F F1 The vehicle should remain upright during and after the collision although moderate roll, pitching, and yawing are acceptable. (Answer Yes or No) Pass Pass YES F2 Maximum roll of the vehicle: ⢠Relative difference is less than 20% or ⢠Absolute difference is less than 5 degrees â11.4 â10.5 7.9% 0.9 deg YES F3 Maximum pitch of the vehicle is: ⢠Relative difference is less than 20% or ⢠Absolute difference is less than 5 degrees â4.2 â5.5 31.0% 1.3 deg YES F4 Maximum yaw of the vehicle is: ⢠Relative difference is less than 20% or ⢠Absolute difference is less than 5 degrees 20.0 10.5 47.5% 9.5 deg NO L L1 OIV: ⢠Relative difference is less than 20% or ⢠Absolute difference is less than 2 m/s ⢠Longitudinal OIV (m/s) 9.8 11.3 15.3% 1.5 m/s YES ⢠Lateral OIV (m/s) â7.7 â7.7 0% 0 m/s YES ⢠THIV (m/s) 12.2 13.3 9.0% 1.1 m/s YES L2 Occupant accelerations: ⢠Relative difference is less than 20% or ⢠Absolute difference is less than 4 gâs ⢠Longitudinal RDA â12.5 â9.4 24.8% 3.1 gâs YES ⢠Lateral RDA 7.0 7.1 1.4% 0.1 gâs YES ⢠PHD 12.5 12.8 2.4% 0.3 gâs YES ⢠ASI 2.17 2.25 3.7% 0.08 YES
112 Evaluation of Bridge Rail Systems to Confirm AASHTO MASH Compliance Table 4.13. Vehicle trajectory phenomena. Evaluation Criteria Known Result Analysis Result Difference Relative/ Absolute Agree? V eh ic le T ra je ct or y M M1 The exit angle from the test article preferably should be less than 60% of test impact angle, measured at the time of vehicle loss of contact with test device. Yes 3.4 deg Yes 2.3 deg YES M2 Exit angle at loss of contact: ⢠Relative difference is less than 20% or ⢠Absolute difference is less than 5 degrees 3.4 deg 2.3 deg 32.4% 1.1 deg YES M3 Exit velocity at loss of contact: ⢠Relative difference is less than 20% or ⢠Absolute difference is less than 10 kmh 54.4 kmh 57.6 kmh 5.9% 3.2 kmh YES M4 One or more vehicle tires failed or de-beaded during the collision event. (Answer Yes or No) Yes Yes YES Summary Validation and verification procedures were completed for the 1100C vehicle model updated to account for tire and suspension failure capability. The updated vehicle model with wheel and suspension failure was considered acceptable for the deck-mounted full-scale crash test and the curb-mounted full-scale crash test. This vehicle model was used to rerun the earlier simulations shown in Chapter 2.
