scholarly journals Performance of Rear Under-Ride Protection Device (RUPD) During Car to Heavy Truck Rear Impact

2019 ◽  
Vol 8 (6) ◽  
pp. 3367-3375
Keyword(s):  
Experimental Tests ◽  
Structure Design ◽  
Design Stage ◽  
Protection Device ◽  
Heavy Vehicles ◽  
Passenger Vehicles ◽  
Rear Impact ◽  
Heavy Trucks ◽  
Heavy Truck ◽  
Crash Tests

Passenger vehicles crashes with Under-ride rear end of heavy vehicles result in fatal injuries due to sliding of passenger car beneath heavy trucks frames. This is related to an improper structure design of rear under-ride protection device (RUPD) that is mounted to the rear of the heavy vehicles. The design of effective RUPD must be taken into consideration during the design stage of truck chassis frame. There are two types of analyses used to investigate the performance of trucks RUPDs such as experimental tests and numerical analysis or simulation. This review aims to discuss the available research methods on the performance of RUPDs during car to heavy truck rear impact, and record their lack and potential areas. Moreover various crash velocities will be discussed for the car-to-heavy truck rear impact tests, as well as different scales of car frontal crash tests are included. Furthermore energy absorption capability of different truck RUPDs designs will be presented in this paper.

Potential Effects of Heavy Vehicles on Operations of Super 2 Highways

2017 ◽  
Vol 2638 (1) ◽  
pp. 10-17 ◽  
Author(s):  
Marcus A. Brewer ◽  
Kay Fitzpatrick
Keyword(s):  
Recent Literature ◽  
Design Guidelines ◽  
Proof Of Concept ◽  
Heavy Vehicles ◽  
Design Features ◽  
High Demand ◽  
Passenger Vehicles ◽  
Sight Distance ◽  
Operational Characteristics ◽  
Heavy Truck

Increasing volumes, specifically heavy truck volumes, have an increasingly greater effect on operations on the nation’s two-lane highways. Various strategies have been implemented to reduce delay and increase capacity, particularly the use of marked passing zones and the addition of periodic passing lanes to allow faster vehicles to pass slower vehicles and to disperse platoons. However, much existing guidance and previous research focused on those design features in the context of passenger vehicles. As the volume of heavy vehicles increases, particularly in high-demand corridors such as those related to energy exploration or manufacturing distribution, so does the number of individual trucks and truck convoys that can further erode operational characteristics on two-lane highways. This paper summarizes existing guidance and recent literature on passing treatments and design guidelines for passing sight distance, passing lanes, and passing zones. This paper also presents results from a proof-of-concept exercise to demonstrate potential effects of trucks on extending the lengths of passing sight distance for certain scenarios.

scholarly journals Is Acceleration a Valid Proxy for Injury Risk in Minimal Damage Traffic Crashes? A Comparative Review of Volunteer, ADL and Real-World Studies

2021 ◽  
Vol 18 (6) ◽  
pp. 2901
Author(s):  
Paul S. Nolet ◽  
Larry Nordhoff ◽  
Vicki L. Kristman ◽  
Arthur C. Croft ◽  
Maurice P. Zeegers ◽  
...  
Keyword(s):  
Real World ◽  
Injury Risk ◽  
Angular Acceleration ◽  
Traffic Crashes ◽  
Rear Impact ◽  
Comparative Review ◽  
Minimal Damage ◽  
Injury Causation ◽  
Crash Tests ◽  
Biomechanical Approach

Injury claims associated with minimal damage rear impact traffic crashes are often defended using a “biomechanical approach,” in which the occupant forces of the crash are compared to the forces of activities of daily living (ADLs), resulting in the conclusion that the risk of injury from the crash is the same as for ADLs. The purpose of the present investigation is to evaluate the scientific validity of the central operating premise of the biomechanical approach to injury causation; that occupant acceleration is a scientifically valid proxy for injury risk. Data were abstracted, pooled, and compared from three categories of published literature: (1) volunteer rear impact crash testing studies, (2) ADL studies, and (3) observational studies of real-world rear impacts. We compared the occupant accelerations of minimal or no damage (i.e., 3 to 11 kph speed change or “delta V”) rear impact crash tests to the accelerations described in 6 of the most commonly reported ADLs in the reviewed studies. As a final step, the injury risk observed in real world crashes was compared to the results of the pooled crash test and ADL analyses, controlling for delta V. The results of the analyses indicated that average peak linear and angular acceleration forces observed at the head during rear impact crash tests were typically at least several times greater than average forces observed during ADLs. In contrast, the injury risk of real-world minimal damage rear impact crashes was estimated to be at least 2000 times greater than for any ADL. The results of our analysis indicate that the principle underlying the biomechanical injury causation approach, that occupant acceleration is a proxy for injury risk, is scientifically invalid. The biomechanical approach to injury causation in minimal damage crashes invariably results in the vast underestimation of the actual risk of such crashes, and should be discontinued as it is a scientifically invalid practice.

Identification of Tire Model Parameters Through Full Vehicle Experimental Tests

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Francesco Braghin ◽  
Federico Cheli ◽  
Edoardo Sabbioni
Keyword(s):  
Laboratory Tests ◽  
Experimental Tests ◽  
Contact Forces ◽  
Lateral Acceleration ◽  
Design Stage ◽  
Model Parameters ◽  
Tire Model ◽  
Identification Procedure ◽  
Sideslip Angle ◽  
Tyre Model

Individual tire model parameters are traditionally derived from expensive component indoor laboratory tests as a result of an identification procedure minimizing the error with respect to force and slip measurements. These parameters are then transferred to vehicle models used at a design stage to simulate the vehicle handling behavior. A methodology aimed at identifying the Magic Formula-Tyre (MF-Tyre) model coefficients of each individual tire for pure cornering conditions based only on the measurements carried out on board vehicle (vehicle sideslip angle, yaw rate, lateral acceleration, speed and steer angle) during standard handling maneuvers (step-steers) is instead presented in this paper. The resulting tire model thus includes vertical load dependency and implicitly compensates for suspension geometry and compliance (i.e., scaling factors are included into the identified MF coefficients). The global number of tests (indoor and outdoor) needed for characterizing a tire for handling simulation purposes can thus be reduced. The proposed methodology is made in three subsequent steps. During the first phase, the average MF coefficients of the tires of an axle and the relaxation lengths are identified through an extended Kalman filter. Then the vertical loads and the slip angles at each tire are estimated. The results of these two steps are used as inputs to the last phase, where, the MF-Tyre model coefficients for each individual tire are identified through a constrained minimization approach. Results of the identification procedure have been compared with experimental data collected on a sport vehicle equipped with different tires for the front and the rear axles and instrumented with dynamometric hubs for tire contact forces measurement. Thus, a direct matching between the measured and the estimated contact forces could be performed, showing a successful tire model identification. As a further verification of the obtained results, the identified tire model has also been compared with laboratory tests on the same tire. A good agreement has been observed for the rear tire where suspension compliance is negligible, while front tire data are comparable only after including a suspension compliance compensation term into the identification procedure.

scholarly journals Reduction of Aerodynamic Drag of Heavy Vehicles using CFD

2021 ◽  
Vol 9 (8) ◽  
pp. 2670-2678
Author(s):  
Priyank Kothari
Keyword(s):  
Fuel Economy ◽  
Aerodynamic Drag ◽  
Fuel Efficiency ◽  
Heavy Vehicles ◽  
Heavy Trucks ◽  
Air Resistance

Abstract: Aerodynamic drag is the force that opposes an object’s motion. When a vehicle no matter the size, is designed to allow air to move fluidly over its body, aerodynamic drag will have less of an impact on its performance and fuel economy. Heavy trucks burn a significant amount of fuel as to overcome the air resistance. More than 50% of an 18-wheeler’s fuel is spent reducing aerodynamic drag on the highways. Keywords: Aerodynamics, Heavy vehicles, ANSYS, Aerodynamic Drag, Fuel efficiency.

Spring Load Restrictions in Finland: Current Policy and Research Implications

1998 ◽  
Vol 1615 (1) ◽  
pp. 29-31
Author(s):  
Jukka Isotalo
Keyword(s):  
Research Programme ◽  
Road Maintenance ◽  
Current Policy ◽  
Heavy Vehicles ◽  
Minimum Standard ◽  
Maximum Weight ◽  
Frost Action ◽  
Heavy Trucks ◽  
Restriction Policy ◽  
National Road

Roads in Finland are exposed to seasonal strength variation. Because of industrial policy, the maximum weight of heavy trucks is 60 metric tons all year. The policies applied by the Finnish National Road Administration (Finnra) to mitigate the effects of seasonal road strength variations on public roads, and the current research on the topic in Finland, are investigated. It has been estimated that the annual cost of road repairs because of spring damages is about $10 million under the present load restriction policy. The costs for road repairs would be $35 million without restrictions. The annual additional cost for all heavy transport is estimated at $15 million. An internal Finnra survey revealed that $80 million to $100 million is needed to repair all known frost-susceptible road sections. Finnra load restrictions are intended to prevent damage to roads by heavy vehicles during spring thaw. The restrictions will reduce and possibly eliminate increases in annual road maintenance costs. On the other hand, the restrictions will allow a minimum standard for vital transport. Finnra’s Road Structures Research Programme (TPPT) studies improvements in the durability, strength, and economy of road structures. A key part of the TPPT project concerns problems associated with frost, especially durability against frost action. The most important factors of frost action on roads are the freezing index, duration of frost and thaw seasons, surface temperature, and ground water level. Methods for testing and calculating frost effects are discussed, as are the questions that must be answered before more precise models can be published.

A Particle Filter Approach for Identifying Tire Model Parameters From Full-Scale Experimental Tests

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Edoardo Sabbioni ◽  
Ruixin Bao ◽  
Federico Cheli ◽  
Davide Tarsitano
Keyword(s):  
Particle Filtering ◽  
Experimental Tests ◽  
Lateral Acceleration ◽  
Design Stage ◽  
Model Parameters ◽  
Tire Model ◽  
Passenger Cars ◽  
Sideslip Angle ◽  
Lane Changes ◽  
Filter Approach

Mathematical models simulating the handling behavior of passenger cars are extensively used at a design stage for evaluating the effects of new structural solutions or control systems. The main source of uncertainty in these type of models lies in tire–road interaction, due to high nonlinearity. Proper estimation of tire model parameters is thus of utter importance to obtain reliable results. This paper presents a methodology aimed at identifying the magic formula-tire (MF-Tire) model coefficients of the tires of an axle only based on measurements carried out on board vehicle (vehicle sideslip angle, yaw rate, lateral acceleration, speed, and steer angle) during standard handling maneuvers (step-steers, double lane changes, etc.). The proposed methodology is based on particle filtering (PF) technique. PF may become a serious alternative to classic model-based techniques, such as Kalman filters. Results of the identification procedure were first checked through simulations. Then, PF was applied to experimental data collected using an instrumented passenger car.

Volumetric Changes of the UHPC Matrix and its Determination

2016 ◽  
Vol 827 ◽  
pp. 215-218 ◽  
Author(s):  
David Čítek ◽  
Milan Rydval ◽  
Jiří Kolísko
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
High Performance Concrete ◽  
Experimental Tests ◽  
Structure Design ◽  
Ultra High Performance Concrete ◽  
Fine Grained ◽  
Durability Properties ◽  
Shrinkage And Creep

Research in the Ultra-High Performance Concrete applications field is very important. Current experiences shows that the structure design should be optimize due to relatively new fine-grained cement-based Hi-Tech material with excellent mechanical and durability properties. It is not sure if some of the volumetric changes like creep or shrinkage has or has not an impact on an advantage for the construction and for the structure design. The effect of the shrinkage and creep of common used concretes are well known and well described at publications but the effect of volumetric changes of the UHPC is mostly unknown because of the fact that some of experimental tests are long term and the development of UHPC is still in its basics. A lot of works are focused on a basic mechanical properties and durability tests.

A Particle Filter Approach for Identifying Tyre Model Parameters From Full-Scale Experimental Tests

2015 ◽  
Author(s):  
Ruixin Bao ◽  
Francesco Braghin ◽  
Federico Cheli ◽  
Edoardo Sabbioni
Keyword(s):  
Particle Filtering ◽  
Experimental Tests ◽  
Lateral Acceleration ◽  
Design Stage ◽  
Model Parameters ◽  
Passenger Cars ◽  
Sideslip Angle ◽  
Tyre Model ◽  
Lane Changes ◽  
Filter Approach

Mathematical models simulating the handling behavior of passenger cars are extensively used at a design stage for evaluating the effects of new structural solutions or control systems. The main source of uncertainty in this type of models lies in the tyre-road interaction, due high nonlinearity. Proper estimation of tyre model parameters is thus of utter importance to obtain reliable results. A methodology aimed at identifying the Magic Formula-Tyre (MF-Tyre) model coefficients of the tyres of an axle based only on the measurements carried out on board vehicle (vehicle sideslip angle, yaw rate, lateral acceleration, speed and steer angle) during standard handling maneuvers (step-steers, double lane changes, etc.) is presented in this paper. The proposed methodology is based on Particle Filtering (PF) technique. PF may become a serious alternative to classic model-based techniques, such as Kalman filters. Results of the identification procedure were first checked through simulations. Then PF was applied to experimental data collected on an real instrumented passenger-car vehicles.

scholarly journals Using Connected Vehicle Data to Reassess Dilemma Zone Performance of Heavy Vehicles

2020 ◽  
Vol 2674 (5) ◽  
pp. 305-314
Author(s):  
Howell Li ◽  
Tom Platte ◽  
Jijo Mathew ◽  
W. Benjamin Smith ◽  
Enrique Saldivar-Carranza ◽  
...  
Keyword(s):  
Red Light ◽  
Field Tests ◽  
Connected Vehicle ◽  
Heavy Vehicles ◽  
Passenger Cars ◽  
Dilemma Zone ◽  
Passenger Vehicles ◽  
Vehicle Data ◽  
The Us ◽  
Position Data

The rate of fatalities at signalized intersections involving heavy vehicles is nearly five times higher than for passenger vehicles in the US. Previous studies in the US have found that heavy vehicles are twice as likely to violate a red light compared with passenger vehicles. Current technologies leverage setback detection to extend green time for a particular phase and are based upon typical deceleration rates for passenger cars. Furthermore, dilemma zone detectors are not effective when the max out time expires and forces the onset of yellow. This study proposes the use of connected vehicle (CV) technology to trigger force gap out (FGO) before a vehicle is expected to arrive within the dilemma zone limit at max out time. The method leverages position data from basic safety messages (BSMs) to map-match virtual waypoints located up to 1,050 ft in advance of the stop bar. For a 55 mph approach, field tests determined that using a 6 ft waypoint radius at 50 ft spacings would be sufficient to match 95% of BSM data within a 5% lag threshold of 0.59 s. The study estimates that FGOs reduce dilemma zone incursions by 34% for one approach and had no impact for the other. For both approaches, the total dilemma zone incursions decreased from 310 to 225. Although virtual waypoints were used for evaluating FGO, the study concludes by recommending that trajectory-based processing logic be incorporated into controllers for more robust support of dilemma zone and other emerging CV applications.

Investigation of Heavy Truck Restraint System Effectiveness Through Finite Element Computer Simulations in Frontal Crashes

2016 ◽  
Author(s):  
Nathan Schulz ◽  
Chiara Silvestri Dobrovolny ◽  
Abhinav Mohanakrishnan
Keyword(s):  
Finite Element ◽  
Injury Severity ◽  
Seat Belt ◽  
Restraint System ◽  
Rigid Barrier ◽  
Heavy Trucks ◽  
Ring Location ◽  
Heavy Truck ◽  
Frontal Crashes ◽  
Occupant Kinematics

Computer finite element simulations play an important role in reducing the cost and time taken for prediction of a crash scenario. While interior crash protection has received adequate attention for automobiles, very little is known for commercial vehicle such as heavy trucks. The understanding of injury types for heavy trucks occupants in relation to different crash scenarios would help mitigation of the injury severity. Finite element computer models of the heavy truck cabin structure, interior cabin components, anthropomorphic test device (ATD) (also called dummy) and passive restraint systems were developed and assembled to simulate head-on crash of a heavy truck into a rigid barrier. The researchers developed a computer simulation parametric evaluation with respect to specific seat belt restraint system parameters for a speed impact of 56.3 km/h (35 mph). Restraint parameter variations within this research study are seat belt load limiting characteristics, inclusion of seat belt pretensioner, and variation of seat belt D-ring location. Additionally an airbag was included to investigate another restraint system. For each simulated impact characteristic and restraint system variation, the occupant kinematics were observed and occupant risks were assessed. Within the approximations and assumptions included in this study, the results presented in this paper should be considered as preliminary guidance on the effectiveness of the use of seat belt as occupant injury mitigation system.

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