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In this contribution, the extended Optimal Uncertainty Quantification framework is integrated within the context of reliability‐based design optimizations (RBDO). By that, all advantages the extended Optimal Uncertainty Quantification framework offers for the polymorphic uncertainty quantification, such as the ability to incorporate exact or bounded moment information on epistemic uncertainties without the requirement of the specification of an underlying probability distribution function, can be utilized in order to identify the mathematically sharpest bounds on probabilities as required in an RBDO‐context. The combined framework is tested by means of a numerical example, in which the production and a simple crash scenario of a car front bumper are investigated. Therein, the optimization objective is the maximization of the dissipated energy during the crash, whilst a predefined failure probability is not exceeded. [ABSTRACT FROM AUTHOR]

Evidence from Arrokoth and comets strongly suggests a very low density for this and similar small Kuiper belt objects. Plausible compositions imply high porosities, in excess of 70%, and low compaction crush strengths. If so, impact craters on Arrokoth (especially Sky, its largest) formed largely by compaction of pore space and material displacement. This is consistent with geological evidence from New Horizons imaging. High porosity reduces cratering efficiency in the gravity regime whereas compaction moves it toward crush strength scaling and increased efficiency. Compaction also guarantees that most impactor kinetic energy is taken up as waste heat near the impact point, with momentum transferred to the rest of the body by elastic waves only. Monte Carlo simulations of Sky‐forming conditions indicate that the momentum imparted likely separated Arrokoth's two lobes, but displacement was limited by dissipation at the neck between them. Unusual strength properties are not required to preserve Arrokoth's bilobate configuration. Plain Language Summary: It has become apparent over the last few years that small asteroids and comets are very underdense compared with the materials they are made of. This means that their total porosities are likely quite high, in excess of 70%, both as tiny voids within particles (so‐called microscopic porosity) and spaces between particles (macroscopic porosity). But none are likely as porous as the distant denizens of the Kuiper belt such as Arrokoth (visited by the New Horizons spacecraft in 2019). This paper concerns impact craters on Arrokoth and similar small bodies, and the rather unusual effects expected. Imagine a fluffy (fine powder) snowball striking a much larger fluffy snowball, only that the snow is not pure ice but a mixture of porous icy, rocky, and carbon‐rich particles. Even at high velocities (>100 s of m/s) craters should mostly form by compacting pore space and pushing material away from the impact point, not the traditional blasting of ejecta back into space. Similar to crush‐up of an automobile bumper, compaction helps to protect from the potentially catastrophic effects of large impacts, such as complete disruption of the target or breakup of bilobate bodies like Arrokoth, and should be incorporated in future collisional evolution studies. Key Points: Arrokoth is likely a low density, highly porous, contact binary planetesimalImpact craters on Arrokoth, and particularly its largest, likely formed as compaction craters, with modest or little ejectaHigh porosity acted to protect Arrokoth from catastrophic disruption, ejecta recoil, and lobe dislocation and rearrangement [ABSTRACT FROM AUTHOR]

There is an increasing demand for lightweight materials in the automobile industry. In this study, the crashworthiness and crash safety performance of automobile bumper beams made of long glass fiber‐reinforced polypropylene (LGFR‐PP) composites were evaluated. First, LGFR‐PP with the 40% glass fiber was prepared by the hot‐melt impregnation method, the mechanical properties and Poisson's ratio of the LGFR‐PP specimens were tested, which are essential for the finite element analysis. Then a finite element model of aluminum alloy and LGFR‐PP bumpers was established to obtain their peak collision force, maximum intrusion, and energy absorption values under longitudinal and angular low‐speed collision conditions. Subsequently, the multi‐objective optimization was generated using optimized Latin square sampling and response surface test design, and the section thickness of the bumper beams was optimized. The results showed that Swift and Hockett's hardening model is suitable for the LGFR‐PP material. Based on the principle of equal stiffness, the mass of the anti‐collision beams made of LGFR‐PP is reduced by 17.4%, the specific energy absorption (SEA) is increased by 6%, and the cost is reduced by 69%, and both the peak impact force and the amount of collision intrusion are reduced. The multi‐objective optimized Latin hypercube experimental showed that the continuously variable cross‐section beam based on the thickness optimization balanced the impact resistance especially SEA and lightweight performance very well. [ABSTRACT FROM AUTHOR]

Automotive head‐up displays (HUDs) use windshields as part of the display system and are used as partial reflectors for reflecting the images formed inside the dash board towards the driver. The locations of the aerial images are usually at the bumper of the vehicle and beyond, depending on the requirements. One of the major issues with such HUD system is the solar loading created by sunlight shining into the system through the image forming optics with focusing properties especially when the sun is shining into the HUD system in an off‐axis manner. This paper describes a HUD system where the imaging system uses a Micro‐Mirror Array Plate (MMAP) with an optical design that eliminates the issues associated with the off‐axis sunlight. Solar loading is an important design criterion as the HUD optics concentrate the sunlight to levels that can damage the display panel. Based on the aerial imaging properties of MMAP, this design would be applicable to the use of Dihedral Corner Reflector Array (DCRA), and Aerial Imaging by Retro‐Reflection (AIRR). Bench‐top system has been set up using MMAP from ASKA3D, Japan with the expected imaging properties. A complete prototype is being fabricated and will be reported. [ABSTRACT FROM AUTHOR]

Crash absorbers made of fibre-reinforced plastics becoming more and more popular to reduce the mass in the front section of cars. Various research projects analysed the high specific energy absorption and the stable crushing behaviour of this material, however without examining the connection to other car body components. This paper focuses on the connection of the crash absorbers to the bumper system, particularly regarding to the crushing behaviour. An initial step focused on the development of a crash absorber made of carbon-fibre-reinforced plastic, which shows similar energy absorption compared to absorbers made of aluminium. A following step investigated various connection concepts using a drop tower. These first connection concepts resulted in unstable crushing behaviour. The finite element simulation of the tests delivered additional information about the reasons for the insufficient crushing behaviour. Subsequently, a simulation of various connection concepts turned out suitable connection concepts. A final drop tower test investigated the best connection concept. The developed connection system shows similar to the unmodified crash absorber stable crushing behaviour. [ABSTRACT FROM AUTHOR]

Bumper stickers and other signs displayed on private motor vehicles are a ubiquitous part of modern mobile American society. Through this medium of expression, thousands of ideas, values, groups, witticisms and expressions of selfhood compete for public attention. The modern urban society is characterized by interactions among anonymous strangers and communications received through mass media sources. Bumper stickers and car signs provide opportunities to (a) interject one's own perspectives, values and statements into the environment of mass-mediated messages; (b) proclaim a unique personal identity through symbols and statements representing one's interests, affiliations, values and claims to glory, thus attempting to escape the anonymity which characterizes much of modern life; and (c) observe new, often creative messages, symbols and usages being introduced into the culture environment of ideas. This study was designed to determine what messages are being displayed on private passenger vehicles, their frequency and the kinds of vehicles most likely to use this medium for expression.

During wheel bumping caused by stochastic road excitation, the wheel performs rotational and translational movements. The bump and rebound wheel velocity leads to significant angular velocities based on the (elasto-)kinematics of the suspension system. Based on the gyroscopic effect, moments arise about the rotating wheel induced by the angular change while bumping. Therefore it leads to undesirable wheel changes and degrades the tire contact and finally decreases the driving stability. A flexible MBS-model of the five-link rear axle system that includes these effects has been built up to allow a detailed investigation of the gyroscopic effect. Using the simulation results, conclusions can be drawn for refining design criteria for the kinematics, elastokinematics and topology of the suspension system to increase the active safety of the vehicle. (© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Focuses on the inclusion of rubber balls in plastic car bumpers which can reduce deformation, according to materials scientist from Pennsylvania State University in University Park who presented the idea during the 2005 fall meeting of the American Chemical Society in Washington, D.C. Views of Tze-Chiang Chung, professor of materials science and engineering at the university, on plastics; Problems behind the combination of rubber with plastics; Key features of the elastomer rubber material.