Browse Topic: Kinematics
Occupant Safety systems are usually developed using anthropomorphic test devices (ATDs), such as the Hybrid III, THOR-50M, ES-2, and WorldSID. However, in compliance with NCAP and regulatory guidelines, these ATDs are designed for specific crash scenarios, typically frontal and side impacts involving upright occupants. As vehicles evolve (e.g., autonomous layouts, diverse occupant populations), ATDs are proving increasingly inadequate for capturing real-world injury mechanisms. This has led to the adoption of computational Human Body Models (HBMs), such as the Global Human Body Models Consortium (GHBMC) and Total Human Model for Safety (THUMS), which offer superior anatomical fidelity, variable anthropometry, active muscle behaviour modelling, and improved postural flexibility. HBMs can predict internal injuries that ATDs cannot, making them valuable tools for future vehicle safety development. This study uses a sled CAE simulation environment to analyze the kinematics of the HBMs
Armored vehicles offer limited view to the driver and crew. Two-dimensional vision-based situational awareness (SA) systems provide the driver a view of the area around the vehicle. The addition of distance to objects can offer a more comprehensive understanding of the surroundings assisting the driver with the locations of obstacles and rollover hazards. Methods currently available or under development for depth perception have issues limiting their utility in the field.. Some interfere with crew operations, others are are too costly, are not covert or require excessive processing. We offer a low-cost and computationally efficient approach called Kinetically Enhanced Situational Awareness (KESA) that derives distance to objects using existing SA sensors and processors combined with a knowledge of vehicle kinematics. We demonstrate how range can be used to enhance and supplement AI based driver assistance and threat warnings.
Innovators at NASA Johnson Space Center have developed a programmable steering wheel called the Tri-Rotor, which allows an astronaut the ability to easily operate a vehicle on the surface of a planet or moon despite the limited dexterity of their spacesuit. This technology was originally conceived for the operation of a lunar terrain vehicle (LTV) to improve upon previous Apollo-era hand controllers. In re-evaluating the kinematics of the spacesuit, such as the rotatable wrist joint and the constant volume shoulder joint, engineers developed an enhanced and programmable hand controller that became the Tri-Rotor.
ABSTRACT This paper explores novel airfoils for rotorcraft applications using a gradient-free, multi-objective genetic algorithm with 2D URANS simulations. The study considers dynamic kinematics at a Reynolds number of 5×105 and a mean Mach number of 0.35. Two optimization scenarios are analyzed: 1) pre-stall kinematics (0° ≤α ≤10°) and 2) dynamic stall kinematics (0° ≤ α ≤ 20°). The paper compares two objective functions: f1, based on the cycle averaged lift, and ˜ f1, which modifies f1 by penalizing hysteresis in the lift coefficient. The effects of uniform vs. fluctuating freestream velocity and reduced frequency on optimal airfoils are also discussed. The proposed optimization approach has resulted in novel airfoil shapes that are characterized by a drooped nose, with a convex surface on the aft upper surface similar to a reflex camber in pre-stall kinematics and less unsteadiness in the air loads for the optimized airfoils under the dynamic stall kinematics.
Plasticized polyvinyl chloride (PVC) has many applications in automotive industry including electrical harnesses, door handles, seat and head rest covers, and instrument panel (IP) and other interior trim. In IP applications, the PVC skin plays a critical role in passenger airbag deployment (PAB) by tearing along the scored edge of the PAB door and allowing the door to open and the airbag to inflate to protect the occupant. As part of the IP, the PVC skin may be exposed to elevated temperatures and ultraviolet (UV) radiation during the years of the vehicle life cycle which can affect the PVC material properties over time and potentially influence the kinematics of the airbag deployment. Chemical and thermal aging of plasticized PVC materials have been studied in the past, yet no information is found on how the aging affects mechanical properties at high rates of loading typical for airbag deployment events. This paper compares mechanical properties of the virgin PVC-based IP skin
Ongoing research in simulated vehicle crash environments utilizes postmortem human subjects (PMHS) as the closest approximation to live human response. Lumbar spine injuries are common in vehicle crashes, necessitating accurate assessment methods of lumbar loads. This study evaluates the effectiveness of lumbar intervertebral disc (IVD) pressure sensors in detecting various loading conditions on component PMHS lumbar spines, aiming to develop a reliable insertion method and assess sensor performance under different loading scenarios. The pressure sensor insertion method development involved selecting a suitable sensor, using a customized needle-insertion technique, and precisely placing sensors into the center of lumbar IVDs. Computed tomography (CT) scans were utilized to determine insertion depth and location, ensuring minimal tissue disruption during sensor insertion. Tests were conducted on PMHS lumbar spines using a robotic test system for controlled loading in flexion
ABSTRACT Dynamic stall continues to be a limiting factor for rotorcraft performance in forward flight. The complex flow physics, resulting from blade kinematics, aeroelastic deformations, and blade-vortex interactions, makes this problem challenging. The availability of results from recent high-fidelity coupled computational aerodynamics-structural dynamics simulations provides an opportunity to gain new insights into the physics of dynamic stall on rotor blades in realistic operating conditions. Recent research efforts have also resulted in the identification of a leading-edge suction parameter (LESP), whose critical value has been shown to correlate with the flow events leading to dynamic stall. Critical LESP is largely independent of motion parameters, and is dependent mostly on the airfoil shape, Reynolds number, and Mach number. In this work, LESP variation along the blades of a UH-60A rotor in forward flight is extracted from high-fidelity computational results. The objective is
In the 1990s and early 2000s, the field of parallel kinematics was viewed as being potentially transformational in manufacturing, having multiple potential advantages over conventional serial machine tools and robots. Many prototypes were developed, and some reached commercial production and implementation in areas such as hard material machining and particularly in aerospace manufacturing and assembly. There is some activity limited to niche and specialist applications; however, the technology never quite achieved the market penetration and success envisaged. Yet, many of the inherent advantages still exist in terms of stiffness, force capability, and flexibility when compared to more conventional machine structures. This chapter will attempt to identify why parallel kinematic machines (PKMs) have not lived up to the original excitement and market interest and what needs to be done to rekindle that interest. In support of this, a number of key questions and issues have been identified
Items per page:
50
1 – 50 of 1070