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2016-04-15
Technical Paper
2015-01-9020
Emre Sert, Pinar Boyraz
Abstract Studies have shown that the number of road accidents caused by rollover both in Europe and in Turkey is increasing [1]. Therefore, rollover related accidents became the new target of the studies in the field of vehicle dynamics research aiming for both active and passive safety systems. This paper presents a method for optimizing the rear suspension geometry using design of experiment and multibody simulation in order to reduce the risk of rollover. One of the major differences of this study from previous work is that it includes statistical Taguchi method in order to increase the safety margin. Other difference of this study from literature is that it includes all design tools such as model validation, optimization and full vehicle handling and ride comfort tests. Rollover angle of the vehicle was selected as the cost function in the optimization algorithm that also contains roll stiffness and height of the roll center.
2016-04-05
Technical Paper
2016-01-0436
Bolin Zhao, Chen Lv, Junzhi Zhang, Theo Hofman, Maarten Steinbuch
Distinguished from the conventional internal combustion engine vehicles, most of the pure electric vehicles are equipped with only a fixed-ratio reduction gear, because of the wide speed range of the electric motor. For most of the vehicle’s speed and acceleration requirements, they can be satisfied through application of only a fixed-ratio reduction gear. However, within some speed range, the operation efficiency of the electric motor is relatively low, which affects the overall energy efficiency of the electric vehicle. Thus, application of a two-speed gearbox is able to remain the electric motor working within high-efficiency range during the whole operation conditions, which has a good potential to further improve the electric vehicle’s energy economy. Based on the above analysis, in this paper, gear ratios of a two-speed transmission system are optimized for an electric passenger car.
2016-04-05
Technical Paper
2016-01-1531
Dale E. Halloway
Occupant Kinematics in Distinct Types of Far-side Impacts Objective: Occupant contacts not on a trajectory not in line with a response to the resultant impact vector are seen as the consequence of post-impact vehicle rotation. This analysis evaluates field data for indications the trajectory occupant contacts indicate in far-side impacts is affected by the acceleration of the vehicle. Methods: Using the WinSMASH calculated moment arm a classification scheme was devised. WinSMASH calculates and reports moment arm length and sign. Moment arm length was used to classify impacts as ‘centric’ or ‘eccentric’ relative to the vehicle center of gravity. A query was made for far-side impacts in CIREN. 111 cases were reviewed and WinSMASH re-run. The results were used to classify impacts by the crush profile center-of-damage and principal direction of force. All AIS 2+ injuries were located on whole body and specific anatomic region mannequins.
2016-04-05
Technical Paper
2016-01-0427
Chang Qi, XiaoLong Feng, Yu du, Shu Yang, Da-Zhi wang
Large rear-dump mining trucks often suffer from rock impacts which cause adverse vibration during loading operation, resulting in structural damage and deteriorated fatigue life of the body. To decrease the body vibration under heavy rocks’ impact loading, an innovative active suspension system concept was put forward for the rear-dump mining trucks in this work. The new system was developed using simulation methods in three steps. Firstly, a simplified multi-body system dynamic model of a 360t load capacity rear-dump mining truck under rock impact was built in ADAMS as a base model. Secondly, by using the joint simulation method, the base model was translated into a system function module in MATLAB, and an active PID control system to adjust the suspension force was designed base on the modules in SIMULINK. Finally, parameter optimization was conducted to guarantee the proposed control system a better damping performance during the loading process.
2016-04-05
Technical Paper
2016-01-0435
Lirong Wang
Speed bumps are a common traffic calming device that uses vertical deflection to slow motor-vehicle traffic in order to improve traffic safety conditions. Such vertical raising of road pavement had been studied and commonly used as a passive method to reduce the speed of vehicle. Speed bumps generally slow vehicle speed to 5–10 mph (8.0–16.1 km/h), and some to 10–20 mph (16–32 km/h). On one side, speed bumps/humps effectively calm traffic speed to protect pedestrians. On the other side, it may cause vehicle damage and passenger discomfort. In Sweden, an evaluation of spinal stress in bus drivers against ISO 2631-5 required that a driver shall encounter less than 150 bumps in a day at the maximum acceptable speed 10 km/h. When a vehicle touches a speed bump, the speed bump receives the energy transferred by the weight and velocity of the vehicle. Harvesting the vibration energy from speed bump becomes a valid solution in areas where grid electricity is economically available.
2016-04-05
Technical Paper
2016-01-1470
Nathan A. Rose, Neal Carter, Gray Beauchamp
Calculating the speed of a yawing and braked vehicle often requires an estimate of the rate at which the vehicle decelerated over the course of its trajectory. During a steering induced yaw, the rotational velocity of the vehicle will typically be small enough that it will not make up a significant portion of the vehicle energy. However, when a yaw is impact induced and the resulting yaw velocity is high, the rotational component of the vehicle’s kinetic energy can be significant relative to the translational component. In such cases, the rotational velocity can have a meaningful effect on the rate at which the vehicle decelerates. In addition to the effects of rotational energy on the deceleration rate, high yaw velocities can also cause steering angles to develop at the front tires because the frictional forces between the tires and ground cause the yaw rotation of the tires to lag behind the yaw rotation of the vehicle.
2016-04-05
Technical Paper
2016-01-1462
Louis R. Peck, Mu-Hua Cheng
Three targeted vehicles of varying size were measured using an optimized, practical photogrammetry technique and the results were compared to measurements acquired via total station. The photogrammetry method included the use of a field-calibrated DSLR camera equipped with a fixed 20mm lens, retro-reflective targets sized for vehicular modeling, and a CNC-machined scale bar. Eight photographs were taken from proper angles and processed using a commercially available photogrammetry package, and that data was merged with the total station data using a cloud-to-cloud registration process for point-to-point comparison of positional data. The average residual between corresponding photogrammetry and total station points was 1.7 mm (N 258, SD = 0.8 mm) with a 95% confidence level of 3.3 mm. Considering this low residual, one of the sample vehicles was re-measured using a high accuracy FARO Arm for comparison to the photogrammetry technique.
2016-04-05
Technical Paper
2016-01-1480
Jakub Zebala, Wojciech Wach, Piotr Ciępka, Robert Janczur
This article presents the results of an analysis of the yaw marks left by a car with nominal pressure in all tires and with zero pressure in one rear tire. The analysis is a continuation of research on influence of reduced tire pressure on car lateral dynamics in a passing maneuver, discussed at the SAE Congress in 2014. Preliminary analysis of yaw marks has shown, that a wheel with zero pressure deposits a yaw mark whose geometry differs from the yaw mark made by a wheel with nominal pressure based on which we could calculate: critical speed, slip angle and longitudinal wheel slip. The aim of the presented research was to analyze the yaw marks left by car with zero pressure in one rear wheel in order to check the possibility of determining the vehicle critical speed, slip angle and longitudinal wheel. It was reached by performing bench and road tests during which the vehicle motion parameters were recorded using GPS Data Logging System.
2016-04-05
Technical Paper
2016-01-1461
William T. Neale, David Danaher, Sean McDonough, Tomas owens
Many of the smart phone devices widely available on the market today have built in functionality and equipment that may prove useful in certain procedures of accident reconstruction testing and analysis. Two technologies found on many of the devices include accelerometers and GPS tracking. Being capable of tracking the position, speed and acceleration of a vehicle being tested is obviously useful, but can a smart phone, enabled with this technology, provide veritable data for use in accident reconstruction? And what factors would affect the accuracy? This paper presents on this topic in three segments. First, the paper provides an overview of the accelerometer and GPS technology that is built in to smart phone devices. Second, this paper evaluates several versions of smart phones and related software that allows a user to track speed, position, acceleration, temperature, and elevation. The smart phones are tested in scenarios simulating walking, running, biking, and driving.
2016-04-05
Technical Paper
2016-01-1483
The objective of this study is to assess the accuracy of using high impact speed frontal barrier crash tests to predict the deformation energy for a lower impact speed frontal barrier crash. To make this prediction, two key assumptions were made: the frontal barrier crash tests are repeatable for the same model vehicle, and the rebound phase in the force vs deflection curve is similar for the same vehicle model regardless of impact speed. For each vehicle to barrier test, the vehicle’s force vs. deflection curve will be created by synchronizing the barrier’s load cell data with a double integration of the vehicle’s accelerometer data. The deformation energy dissipated during each barrier impact will be calculated by integrating the corresponding force vs. deflection curve. To verify that all deformation energy was accounted for in the test data, the deformation energy will be used to calculate the test EBS.
2016-04-05
Technical Paper
2016-01-1530
Yury Chudnovsky, Justin Stocks-Smith, Jeya Padmanaban, Joe Marsh
A comprehensive review of technical literature addressing injury risk in near- and far-side impacts was performed, and NASS/CDS data (1998-2013) was examined to address serious injury rates, sources, and nature for belted drivers in side impacts. Frequency and severity of near- and far-side impacts by crash severity (delta-V) were compared for older (1994 – 2007 MY) and newer vehicles (2008+ MY). For 2008 MY, individual cases were examined for serious injury factors in far-side impacts. Near- and far-side impacts were identified using principal direction of force and general area of damage. Results show that about 90% of NASS/CDS side impacts have a delta-V under 15 mph for both older and newer cars. The serious injury rate for belted drivers in older cars is 5.5% for near-side crashes and 1.2% for far-side crashes. For newer models, the serious injury rate for belted drivers is 2.5% near-side and 0.5% far-side.
2016-04-05
Technical Paper
2016-01-1532
Kyoungtaek Kwak, Seungwoo SEO, Randi Potekin, Antoine Blanchard, Alexander Vakakis, Donald McFarland, Lawrence Bergman
In order to secure the safety of the passengers, the door should be kept closed during side impact crash and many car makers conduct a various research on this area. Typically, there are two major factors that affect the opening of door during side impact crash tests. One is a physical failure such as the damage of linkage of door locking system, which can be intuitively analyzed and resolved. The other is the inertia effect due to the instantaneous impact and deformation between a barrier and door outer panel. In case that the door opening is, however, resulted from the inertia effect, it is difficult to be intuitively resolved because it takes extremely short time less than 30ms for a whole phenomenon to come out. Also, because the randomly deformed outer panel due to the crash generates not only translational but also angular accelerations that more complicatedly affect dynamic behavior of door handle.
2016-04-05
Technical Paper
2016-01-1477
The ability to accurately calculate a snowmobile’s speed based on measured track marks in the snow is important when assessing a snowmobile accident. The characteristics and length of visible snowmobile track marks were documented for 41 locked-track braking tests and 38 rolldown tests using four modern snowmobiles on a groomed/packed snow surface. The documented track mark lengths were used to quantify the uncertainty associated with using track mark length to estimate initial speed. Regression models were developed for both data sets. The regression model of the locked-track tests revealed that using an average deceleration of 0.36g over the length of the locked track mark provides a good estimate of the best-fit line through the data, with the upper and lower 95th percentile prediction interval bounds best represented by using deceleration rates of 0.23g and 0.52g respectively.
2016-04-05
Technical Paper
2016-01-0432
Xincheng Liang
Vibration energy may cause thermal failure of shock absorber when vehicles are driving on the terrible roads. If the energy can be regenerated, the thermal failure is eliminated entirely and the driving range is enhanced a lot for electric vehicles. Hence, a system of recycling vibration is proposed, and some curves, including force-displacement and rotating speed of the motor, are also got in the paper. In order to validate the credibility of simulations, a test bench is built and concerned data have been collected. In addition, some factors, which are closely related to the performance of riding comfort, are analyzed. Simulation and experiment results indicate bubbles in the oil are vital to the reliability of recycling system, and the damping resistance should be in the more appropriate scope. So the structure of recycling vibration system must be optimized, and the more excellent feature of recycling system is expected.
2016-04-05
Technical Paper
2016-01-0149
Mehdi Jalalmaab, Mohammad Pirani
This paper presents a multi-agent estimation approach to identify unknown parameters of autonomous vehicle environment in presence of communication fault in vehicular network. For some application, e.g. look-ahead road condition estimation, it is required for an agent to have access to other agents’ measurements, particularly frontal vehicles to predict the upcoming situations. By taking the advantage of the hybrid nature of the cooperative estimation problem, short time scale for V2V communication and longer time scale for single agent estimation convergence, the authors provide a multi agent consensus estimation, with an observer to access other agents’ measurements even for out of range agents in faulty network. Furthermore, the described estimation strategy is implemented in an adaptive model predictive collision avoidance policy for unknown road condition driving situation to demonstrate the application of proposed cooperative estimation.
2016-04-05
Technical Paper
2016-01-1472
Dietmar Otte, Martin Urban lng, Heiko Johannsen PhD
This paper shows a new method for generating pre-crash scenarios directly from the reconstruction of the accident by using the software PC-Crash . The new method has been developed by the Medical University Hannover and the Fraunhofer Institute for Transportation Dresden based on transferring all information (participant-, vehicle-, environment- and motion-data) from the reconstruction file of in-depth-data into a scenario-database. In order to analyse boundary conditions (e.g. introduction of certain active safety systems), a so-called Pre Crash Matrix (PCM) of time related parameter of the pre crash phase was developed by the Dresden Accident Research Team (VUFO) in 2008 . By using the PCM and including 5 seconds before the crash, the driving behaviours of the vehicles is digitalized out of PC-Crash data and the scenarios are analysed, whether or not a sensor system would have been able to recognise the dangerous situation in time to avoid or mitigate the accident.
2016-04-05
Technical Paper
2016-01-1484
Terry D. Day
This paper presents the application of simulation software to reconstruct the famous car chase scene from the 1968 movie “Bullit.” In this car chase, a 1968 Ford Mustang, driven by Lt. Frank Bullit of the San Francisco Police Department, is chasing a criminal driving a 1968 Dodge Charger through the hilly streets of the Russian Hill district of San Francisco. The purpose of the simulation was to reconstruct the chase scene to determine the level of realism. To produce the simulation, several city blocks of the pertinent area of the city were surveyed and exemplar vehicles were measured and inspected. 3-dimensional computer models of the scene and vehicles were built. The movie footage was analyzed to determine driver inputs and vehicle speeds. The event was then simulated using 3-dimensional simulation software. The results of the simulation confirmed the vehicles could not have navigated through the course at the speeds shown in the movie.
2016-04-05
Technical Paper
2016-01-1482
Paul Montalbano, Daniel Melcher, Rachel Keller, Thomas Rush, Jay Przybyla
There have been a number of methods presented previously in the literature that attempt to address the challenging process of determining the actual impact speed of a motorcycle at its point of contact with another, typically larger and heavier, vehicle or object. Published works specifically addressing the impact speed portion of the event have included the utilization of the conservation of rotational momentum, the use of crush-based methodologies utilizing the damage profiles of both the motorcycle and the struck vehicle, the application of the conservation of linear momentum, or computer simulation modeling. However, all of the introduced methods to date have known limitations and challenges in gathering adequate data. Unlike passenger vehicles and commercial vehicles, most motorcycles and scooters carry no on-board electronic data recorders to provide insight into the impact phase of the collision.
2016-04-05
Technical Paper
2016-01-1370
Vali Farahani, Salamah Maaita, Aditya Jayanthi
During the course of automobile Instrument Panel (IP) design development, the occupant head impact CAE simulation on IP are routinely performed to validate FMVSS201 requirements. Based on FMVSS201 requirements, the potential head impact zones on the IP are first identified. Then, the head impact zones are used to locate the various target points that must be impacted on IP. Once the critical target locations on IP are chosen, there are several computational steps that are required to calculate impact angles and head form (HF) center of rotation in reference to target points. Then, CAE engineer performs a repetitive process that involves positioning each individual HF with proper impact angle, assigning initial velocity to HF, and defining surface contacts within the finite element model (FEM). To simplify these lengthy manual steps, a commercially available CAE software tool is used to automate these steps.
2016-04-05
Technical Paper
2016-01-1517
Cole R. Young PE, David J. King, James V. Bertoch
The purpose of this study was to characterize the kinematics of four Chevrolet Tracker rollover tests and to determine their average and intermediate deceleration rates while traveling on concrete and dirt. Single vehicle rollover tests were performed using four 2001 Chevrolet Trackers fitted with six degree of freedom kinematic sensors. Tests were conducted using a rollover test device (RTD) in accordance with SAE J2114. The test dolly was modified (resting height of the vehicle wheels was raised) between tests 1, 2, and 3. The RTD was accelerated to 15.6 m/s (35 mph) and then decelerated rapidly by an energy absorbing crash cushion (EA) to cause the vehicle to launch and roll. The vehicles initially rolled on a smooth concrete surface and continued into loose dirt. This paper adds to the body of work identifying phases of constant deceleration during staged RTD tests and compares these phases to the overall deceleration rate.
2016-04-05
Technical Paper
2016-01-1467
Improvements in computer image processing and identification capability have led to programs that can rapidly perform calculations and model the three-dimensional spatial characteristics of objects simply from photographs or video frames. This process, known as structure-from-motion or image based scanning, is a photogrammetric technique that analyzes features of photographs or video frames from multiple angles to create dense surface models or point clouds. Concurrently, unmanned aircraft systems have gained widespread popularity due to their reliability, low-cost, and relative ease of use. These aircraft systems allow for the capture of video or still photographic footage of subjects from unique perspectives. This paper explores the efficacy of using a point cloud created from unmanned aerial vehicle video footage with traditional single-image photogrammetry methods to recreate physical evidence at a crash scene.
2016-04-05
Technical Paper
2016-01-1536
Chung-Kyu Park, Cing-Dao Kan
The vehicle crash pulse severity is a measure of how severely the vehicle crash pulse has an effect on the occupant injury. The objective of this research is to evaluate the assessability of vehicle crash pulse severity in frontal New Car Assessment Program (NCAP) tests. In this study, the existing metrics derived from vehicle crash pulse in the frontal impact are reviewed and categorized into 4 groups in the way of how occupant responses are considered. Then the severity of vehicle crash pulses of the frontal NCAP tests was evaluated by existing metrics. A total of 60 frontal NCAP test data collected from the MY 2012 vehicle test program are analyzed. The linear regression analyses and sled test simulations are conducted to identify their correlation to other metrics and dummy injuries. The results show that some of existing metrics are able to assess crash pulse severity in frontal NCAP tests.
2016-04-05
Technical Paper
2016-01-1475
Toby Terpstra, Tilo Voitel, Alireza Hashemian
Video and photo based photogrammetry software has been utilized in the accident reconstruction community for decades. It has continued to develop in its ease of use, cost, and effectiveness in determining three dimensional data points from two dimensional photographs. Contemporary photogrammetry software packages offer an automated solution capable of generating dense point clouds with millions of 3D data points from multiple images. While alternative modern documentation methods exist, including LiDAR technologies such as 3D scanning, which provide the ability to collect millions of highly accurate points in just a few minutes, the appeal of automated photogrammetry software as a tool for collecting dimensional data is the minimal equipment and ease of use. This research, evaluates the accuracy and capabilities of four automated photogrammetry based software programs to accurately obtain 3D point clouds, by comparing the results to the more established method of 3D scanning.
2016-04-05
Technical Paper
2016-01-1512
Jeya Padmanaban, Roger Burnett, Andrew Levitt
This paper updates the findings of prior research addressing the relationship between seatback strength and likelihood of serious injury/fatality to belted drivers and belted rear seat occupants in rear-impact crashes. Statistical analyses were performed using 1995-2014 CY police-reported crash data from fifteen states. Seatback strength for over 100 vehicle models (model years 1996-2013) was included in the analysis. Seatback strength is measured in terms of the maximum moment that results in 10 inches of seat displacement. These measurements range from 5,989 in-lbs to 39,918 in-lbs, resulting in a wide range of seatback strengths. Additional analysis was done to see whether Seat Integrated Restraint Systems (SIRS) perform better than conventional belts in reducing driver and rear seat occupant injury in rear impacts. Field data shows the injury rate for belted drivers and belted rear seat occupants in rear-impact crashes is less than 1%.
2016-04-05
Technical Paper
2016-01-1464
Jorge Martins, Ricardo Ribeiro, Pedro Neves, F. P. Brito
The process for accident reconstruction may be very complex and there are various studies and methodologies to analyse collisions and reconstruct the accident. CRASH 3 is one of such methodologies for accident reconstruction. This program is comprised of two distinct and independent modules, one for the trajectory analysis and the other one for damage analysis. This paper will focus on the latter part, damage analysis. The main interest of the research is the ability to create a database based on crash-test data and use it in an already existing model for damage evaluation. This model calculates the dissipated energy associated to the damaged area of the vehicle during the accident. Various organizations over the world perform crash-tests of vehicles, but the major databases are those kept by the NHTSA (of the USA) and Euro NCAP (of Europe).
2016-04-05
Technical Paper
2016-01-1540
Timothy Keon
The National Highway Traffic Safety Administration (NHTSA) has performed prior research investigating THOR 50th male (THOR-50M) response in Oblique crash tests. This research is being expanded to investigate THOR-50M in the driver position in a 56 kph frontal rigid barrier crash event. In addition, Hybrid III 5th adult female (AF05) ATDs are used in this testing to evaluate the RibEye Deflection Measurement System. The AF05 ATDs are positioned in the right front passenger and right rear passenger seating positions. For the right front position, the NCAP seating procedure was used with the seat fore-aft position set to mid-track. For the right rear position, the seating procedure used was from the FMVSS 214 Side Impact TP. The NCAP Frontal Impact Testing test procedure was followed for test setup and execution. Some additional instrumentation on the vehicle as well as some additional measurements was added to this test setup.
2016-04-05
Technical Paper
2016-01-1473
Orion P. Keifer, Bradley Reckamp, Charles Moody, Anthony Timpanaro
Evaluation of the severity of low speed motor vehicle crashes have been the subject of significant research for more than 20 years. These crashes typically involve no or very minor damage to the vehicles involved and therefore the ability to determine the threshold of damage would be very useful in analysis of such cases. One such threshold, which has been used by accident reconstructionist, is the manufacturer’s published bumper rating in compliance with Federal Motor Vehicle Safety Standards (FMVSS) for Vehicle Bumpers. The rationale is that if there is any damage to the bumper system of the vehicle in question, the impact must have had a change in velocity greater than the bumper rating. While attractive, due to its simplicity, the rational is not supported by the data.
2016-04-05
Technical Paper
2016-01-1466
Bradley C. Reckamp, Charles Moody, Anthony Timpanaro, Orion Keifer
A common low speed motor vehicle collision scenario occurs in heavy traffic situations between two or more vehicles which were stopped in traffic prior to the collision. While information regarding the pre-collision spacing of the involved vehicles can be very useful to an accident reconstructionist, witness perceptions and statements regarding the distance between the stopped vehicles, prior to the collision, can be remarkably inaccurate. Physical evidence regarding pre-collision spacing is also unavailable in most cases. A study was conducted of several selected intersections in four major metropolitan areas in the United States of America (Washington, District of Columbia; Jacksonville, Florida; Chicago, Illinois; and Los Angeles, California). Publicly available aerial photography, rectified and scaled, was used to perform a statistical analysis of the distance between stopped passenger vehicles at busy traffic signalized intersections.
2016-04-05
Technical Paper
2016-01-1485
Noritoshi Atsumi, Yuko Nakahira, Masami Iwamoto, Satoko Hirabayashi, Eiichi Tanaka
The reduction of higher brain dysfunction due to traumatic brain injury (TBI) caused by head rotational impact in traffic accidents is needed. However, the injury mechanism still remains unclear. Brain parenchyma of the head finite element (FE) model has been generally modeled as simple isotropic viscoelastic materials in past analyses. In this study, we developed a new constitutive model describing most of the mechanical properties in brain parenchyma such as anisotropy in white matter, strain rate dependency, and the characteristics in unloading process for further understanding of TBI mechanism. The validation of the constitutive model were performed against several material test data from the literature by using simple one element model. The model was also introduced into the human head FE model of THUMS v4.02 and then validated against post mortem human subjects (PMHS) test data about brain tissue displacements under rotational impacts.
2016-04-05
Technical Paper
2016-01-1486
Qi Zhang, Bronislaw Gepner, Jacek Toczyski, Jason Kerrigan
While over 30% of US occupant fatalities occur in rollover crashes, no dummy has been developed for such a condition. Currently, an efficient, cost-effective methodology is being implemented to develop a biofidelic rollover dummy. Instead of designing a rollover dummy from scratch, this methodology identifies a baseline dummy and modifies it to improve its response in rollover. Using computational models of the baseline dummy (both multibody and FE), the dummy’s structure was continually modified until its response was aligned (using BioRank metric) with biofidelity targets. A previous study (Part I) identified the THOR dummy as a suitable baseline dummy by comparing the kinematic responses of six existing dummies with PMHS response corridors through laboratory rollover testing. In this study (Part II), the whole-body kinematic response of THOR multibody and FE models were validated with responses of the physical THOR dummy in experiments that simulated rollover conditions.
Viewing 1 to 30 of 3211

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