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1. Morphing Capabilities and Safe Operation Zone of the Utility Truck Boom Equipment

   https://doi.org/10.1115/IMECE2020-24283  

   Patel, Parth Y. ; Happawana, Gemunu ; Vantsevich, Vladimir V. ; Boger, David ; Harned, Chris ( November 2020 , IMECE2020 Proceedings)

   Utility trucks are the first responders in extreme climate and severe weather situations, for saving people’s lives to restoring traffic on the roads. However, such trucks can create dangerous situations on the roads, and off-road conditions, while moving, and performing tasks. Trucks equipped with large booms for reaching elevated heights can become unstable due to their geometry change, which can cause a drastic variation of the truck-boom system’s moment of inertia, and the extreme weight re-distribution among the wheels. Morphing capabilities of the utility trucks need to be investigated together with the vehicle-road forces in order to hold the vehicle safe on the roads.

   In this research paper, static analysis and range of the normal reaction at the wheel of the utility truck is performed to characterize a safe working zone of the boom equipment when the truck is in the flat and titled surface. The analysis is performed for 5-degree of freedom boom equipment with revolute and translational joints in a complex constrained space given by the truck design using 3D moment and force-vector analysis. The possible morphing configuration of the boom equipment is examined in order to define static normal reactions at the wheel-road interaction.

   Further, themore »morphing of the boom equipment is investigated to determine limiting configurations that can be reached without rolling over the truck. In this analysis, it is assumed that the wheels provide enough friction between the tires and road so that tire slippage does not extensively occur, and the utility truck is assumed as a rigid body. In this study, utility truck equipped with boom equipment is utilized in this study for numerical illustration.

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2. Nonlinear finiteelementanalysisofliquidsloshingincomplex vehiclemotionscenarios

   https://doi.org/doi.org/10.1016/j.jsv.2017.05.021  

   Nicolsen, Nicolsen ; Wang, Liang ; Shabana, Ahmed ( October 2017 , Journal of sound and vibration)

   .The objective of this investigation is to develop a new total Lagrangian continuum-based liquid sloshing model that can be systematically integrated with multibody system (MBS) algorithms in order to allow for studying complex motion scenarios. The new approach allows for accurately capturing the effect of the sloshing forces during curve negotiation, rapid lane change, and accelerating and braking scenarios. In these motion scenarios, the liquid experiences large displacements and significant changes in shape that can be captured effectively using the finite element (FE) absolute nodal coordinate formulation (ANCF). ANCF elements are used in this investigation to describe complex mesh geometries, to capture the change in inertia due to the change in the fluid shape, and to accurately calculate the centrifugal forces, which for flexible bodies do not take the simple form used in rigid body dynamics. A penalty formulation is used to define the contact between the rigid tank walls and the fluid. A fully nonlinear MBS truck model that includes a suspension system and Pacejka’s brush tire model is developed. Specified motion trajectories are used to examine the vehicle dynamics in three different scenarios – deceleration during straight-line motion, rapid lane change, and curve negotiation. It is demonstrated thatmore »the liquid sloshing changes the contact forces between the tires and the ground – increasing the forces on certain wheels and decreasing the forces on other wheels. In cases of extreme sloshing, this dynamic behavior can negatively impact the vehicle stability by increasing the possibility of wheel lift and vehicle rollover.« less
3. Experimental Investigation of the Tractive Performance of Pneumatic Tires on Ice

   https://doi.org/10.2346/tire.18.460409  

   Jimenez, Emilio ; Sandu, Corina ( January 2020 , Tire Science and Technology)

   ABSTRACT This investigation was motivated by the need for performance improvement of pneumatic tires in icy conditions. Under normal operation, the pneumatic tire is the only force-transmitting component between the terrain and the vehicle. Therefore, it is critical to grasp the understanding of the contact mechanics at the contact patch under various surfaces and operating conditions. This article aims to enhance the understanding of the tire-ice contact interaction through experimental studies of pneumatic tires traversing over smooth ice. An experimental design has been formulated that provides insight into the effect of operational parameters, specifically general tire tread type, slip ratio, normal load, inflation pressure, ice surface temperature, and traction performance. The temperature distribution in the contact patch is recorded using a novel method based on thermocouples embedded in the contact patch. The drawbar pull is also measured at different conditions of normal load, inflation pressure, and ice temperatures. The measurements were conducted using the Terramechanics Rig at the Advanced Vehicle Dynamics Laboratory. This indoor single-wheel equipment allows repeatable testing under well-controlled conditions. The data measured indicates that, with the appropriate tread design, the wheel is able to provide a higher drawbar pull on smooth ice. With an increase in icemore »surface temperature, a wet film is observed, which ultimately leads to a significant decrease in traction performance.« less
4. Rolling-Type Isolation: An Experimental Characterization and Numerical Parametric Study

   https://doi.org/11244/53085  

   Casey, Corey ( December 2017 , The University of Oklahoma Libraries)

   Building contents and nonstructural components are known to be vulnerable during seismic events. Of particular concern is computer and network equipment that is critical in the post-earthquake recovery process. A solution for mitigating the seismic hazard to such systems is rolling-type isolation systems (RISs), but the characterization of RISs with realistic loading conditions and system setups is not well documented. An experimental parametric case study was performed varying the mass eccentricity, the number of cabinets, and the damping to simulate in-service conditions. A series of free response tests was performed using an abrupt shake table displacement (pulse) along with forced response tests utilizing the VERTEQ-II Zone-4 waveform. An array or string potentiometers and accelerometers measured the longitudinal, transverse, and rotational responses of the systems. Supplementally damped systems were found to have increased rotations when a mass eccentricity was present. The increase in system size and mass reduced the overall rotations due to an increased restoring moment arm and higher mass moment of inertia. Increased damping decreased the displacement demand on the isolator but increased the overall accelerations slightly. However, the systems without the supplemental damping had such large displacements that impacts were experienced causing excessively high accelerations. Durability was anmore »issue for lightly damped systems due to increased contact stress between the ball and concave rolling surface. A physics-based mathematical model was developed for the prediction of the response of multi-unit RIS arrays with mass eccentricity. The model was first calibrated to the experimental free response tests and then validated with the forced response tests. The validated model was then used to perform a numerical parametric case study. Configurations with one, two, four and eight cabinets were modeled, and the eccentricity was varied. The VERTEQ-II waveform was applied in both the front-to-back and side-to-side directions under varying ground motion scaling. Impacts are predicted at lower ground motion scaling with larger mass eccentricity due to the initiation of rotations. The ground motion scaling for which impacts occur is increased due to the systems higher resistance to rotations from increased number of isolated cabinets. Finally, capacity design curves for the impact point were determined, which can be used to establish the required configuration (number of cabinets and eccentricity) for a given ground motion intensity.« less
5. Vehicle Lateral Motion Stability Under Wheel Lockup Attacks

   Mohammadi, Alireza ; Malik, Hafiz ( January 2022 , Workshop on Automotive and Autonomous Vehicle Security (AutoSec) 2022)

   Motivated by ample evidence in the automotive cybersecurity literature that the car brake ECUs can be maliciously reprogrammed, it has been shown that an adversary who can directly control the frictional brake actuators can induce wheel lockup conditions despite having a limited knowledge of the tire-road interaction characteristics [1]. In this paper, we investigate the destabilizing effect of such wheel lockup attacks on the lateral motion stability of vehicles from a robust stability perspective. Furthermore, we propose a quadratic programming (QP) problem that the adversary can solve for finding the optimal destabilizing longitudinal slip reference values.