Search Results

This paper presents a design method for continuous fiber composites in three-dimensional space with locally varying orientation distribution and their fabrication method. The design method is formulated based on topology optimization by augmented tensor field design variables. The fabrication method is based on Tailored Fiber Placement technology, whereby a CNC embroidery machine prepares the preform. The fiber path is generated from an optimized orientation distribution field. The preform is formed with vacuum-assisted resin transfer molding. The fabricated prototype weighs 120 g, a 70% weight reduction, achieving 3.5× mass-specific stiffness improvement.

Wireless Power Transfer (WPT) promises automated and highly efficient charging of electric and plug-in-hybrid vehicles. As commercial development proceeds forward, the technical challenges of efficiency, interoperability, interference and safety are a primary focus for this industry. The SAE Vehicle Wireless Power and Alignment Taskforce published the Recommended Practice J2954 to help harmonize the first phase of high-power WPT technology development. SAE J2954 uses a performance-based approach to standardizing WPT by specifying ground and vehicle assembly coils to be used in a test stand (per Z-class) to validate performance, interoperability and safety. The main goal of this SAE J2954 bench testing campaign was to prove interoperability between WPT systems utilizing different coil magnetic topologies. This type of testing had not been done before on such a scale with real automaker and supplier systems.

Petit et al. 2015 and Lebarbé et al. 2016 reported on two studies where the injury mechanism and threshold of the sacroiliac joint were investigated in two slightly oblique crash test conditions from 18 Post Mortem Human Subjects (PMHS) tests. They concluded that the sacroiliac joint fractures were associated with pubic rami fractures. These latter being reported to occur first in the time history. Therefore it was recommended not to define a criterion specific for the sacroiliac joint. In 2012, injury risk curves were published for the WorldSID dummy by Petitjean et al. For the pelvis, dummy and PMHS paired tests from six configurations were used (n = 55). All of these configurations were pure lateral impacts. In addition, the sacroiliac joint and femur neck loads were not recorded, and the dummy used was the first production version (WorldSID revision 1). Since that time, the WorldSID was updated several times, including changes in the pelvis area.

The purpose of this paper is to construct the thermal analysis model by measuring and estimating the temperature at the traction contact area. For measurement of temperature, we have used a thin-film temperature sensor. For estimation of temperature, we have composed the thermal analysis model. The thin-film temperature sensor was formed on the contact surface using a spattering device. The sensor is constituted of three layers (sensor layer, insulation layer and intermediate layer). Dimensions of the sensor were sufficiently smaller than the traction contact area. The sensor featured high specific pressure capacity and high speed responsiveness. The thermal analysis model was mainly composed of three equations: Carslaw & Jaeger equation, Rashid & Seireg equation and heat transfer equation of shear heating in oil film. The heat transfer equation involved two models (local shear heating model at middle plane, homogeneous shear heating model).

This paper proposes a theory to analyze the collision avoidance capability of automated driving technologies. The theory gives answers to a fundamental question whether automated vehicles fall into extreme conditions at all rather than another question how a vehicle reacts under extreme conditions (is it as safe as driver?). The theory clarifies the following matters: There are two types of hazards to cause collisions, cognitive hazards and behavioral hazards. Cognitive hazards are handled by controlling the upper limit speed of the automated vehicle including when stopped. There are two methods for handling behavioral hazards, preparation and response. The response known well is the coping method activated when the hazard is detected in the dynamic (operational) level. The preparation is the coping method operating at all time in the semantic (tactical) level.

In an evaluation of crashworthiness for the cars made of aluminum alloys, the evaluation considering fracture phenomenon comes to be needed because conventional aluminum alloys have low fracture strain (10-20%). In case of the development of a B-Pillar made by die cast, if crack occurrence, furthermore, separation of a part can be estimated by using CAE in crashworthiness evaluations, we can reduce the number of prototype makings and the cost of development using expensive dies. Therefore, we performed crashworthiness evaluations by CAE using some sort of a damage & fracture material model. It is known as “Orthotropic damage & fracture model”.

In order to achieve the Toyota Environmental Challenge of 2050 (zero CO2 emissions), we have developed an innovative coating system that achieves more than 95% transfer efficiency. In order to reduce paint loss in the painting process, it is necessary to eliminate overdust and bounce dust. The most important point is how to spray (atomization, particle flight, adhesion) without shaping air. We have developed a “super high transfer efficiency system” that eliminates the need for shaping air. We continue to challenge the development of innovative technologies to view the paint shop as clean and eco-friendly environment.

Compatibility in vehicles crashes has been studied worldwide in recent years. In cases where primary energy-absorbing structures such as front end members were bypassed in front-to-front collisions, energy-absorbing efficiency declined compared to cases when no such bypassing occurred. A bumper beam that connects the front end members in the transverse direction can help prevent bypassing of primary energy-absorbing structures. The strength balance between front end members and a bumper beam was studied in this paper. It was verified in front-to-front offset vehicle collision tests that crash energy can be efficiently absorbed by balancing the strength of the bumper beam with the compression strength of the front end members.

In the 1st generation Toyota "MIRAI" fuel cell stack, carbon protective surface coating is deposited after individual Ti bipolar plate being press-formed into the desired shape. Such a process has relatively low production speed, not ideal for large scale manufacturing. A new coating concept, consisting of a nanostructured composite layer of titanium oxide and carbon particles, was devised to enable the incorporation of both the surface treatment and the press processes into the roll-to-roll production line. The initial coating showed higher than expected contact resistance, of which the root cause was identified as nitrogen contamination during the annealing step that inhibited the formation of the composite film structure. Upon the implementation of a vacuum furnace chamber as the countermeasure, the issue was resolved, and the improved coating could meet all the requirements of productivity, conductivity, and durability for use in the newer generation of fuel cell stacks.

In this paper, we will introduce a stereo vision system developed as a sensor for a vehicle's front monitor. This system consists of three parts; namely, a stereo camera that collects video images of the forward view of the vehicle, a stereo ECU that processes its output image, and a near-infrared floodlight for illuminating the front at night. We were able to develop an obstacle detection function for the Pre-Crash Safety System and also a traffic lane detection function for a Lane-Keeping Assist System. Especially in regard to the obstacle detection function, we were able to achieve real-time processing of the disparity image calculations that had formerly required long processing times by using two types of recently developed LSIs.

Toyota Motor Corporation has mass-produced turbochargers with silicon nitride ceramic rotors since October, 1989. Those turbochargers have been introduced into Celica and MR-2 which are Toyota sporty-type passenger cars. The designing of ceramic rotor was carried out in order to ensure the strength and durability of the component as well as to obtain the same aerodynamic characteristics as in the metal rotor. A moment of inertia was reduced by 60% using ceramic rotor which improved turbocharger response. The ceramic rotor was joined to metal shaft by new method which compensated problems in both shrink fitting and active brazing methods. High temperature strength of silicon nitride material was improved by controlling the amount of sintering additives and sintering conditions. The ceramic injection moulding was employed to mass-produce rotors with complicated shape, applying optimun binder compositions and moulding conditions.

This paper describes a method for assisting pedestrians to cross a road. As motorization develops, pedestrian protection techniques are becoming more and more important. Advanced driving assistance systems (ADAS) are improving rapidly to provide even greater safety. However, since the accident risk of pedestrians remains high, the development of an advanced walking assistance system for pedestrian protection may be an effective means of reducing pedestrian accidents. Crossing a road is one of the highest risk events, and is a complex phenomenon that consists of many dynamically changing elements such as vehicles, traffic signals, bicycles, and the like. A road crossing assistance system requires three items: real-time situational recognition, a robust decision-making function, and reliable information transmission. Edge devices equipped with autonomous systems are one means of achieving these requirements.

Injuries in car to pedestrian collisions are affected by various factors such as the vehicle body type, pedestrian body size and impact location as well as the collision speed. This study aimed to investigate the influence of such factors taking a Finite Element (FE) approach. A total of 72 collision cases were simulated using three different vehicle FE models (Sedan, SUV, Mini-Van), three different pedestrian FE models (AM50, AF05, AM95), assuming two different impact locations (center and the corner of the bumper) and at four different collision speeds (20, 30, 40 and 50 km/h). The impact kinematics and the responses of the pedestrian model were validated against those in the literature prior to the simulations. The relationship between the collision speed and the predicted occurrence of head and chest injuries was examined for each case, analyzing the impact kinematics of the pedestrian against the vehicle body and resultant loading to the head and the chest.

This paper describes impact kinematics and injury values of Hybrid III AM50, THOR AM50 and THUMS AM50 in simulated oblique frontal impact conditions. A comparison was made among them in driver and passenger seat positions of a midsize sedan car finite element (FE) model. The simulation results indicated that the impact kinematics of THOR was close to that of THUMS compared to that of the Hybrid III. Both THOR and THUMS showed z-axis rotation of the rib cage, while Hybrid III did not. It was considered that the rib cage rotation was due primarily to the oblique impact but was allowed by flexibility of the lumbar spine in THOR and THUMS. Lateral head displacement observed in both THOR and THUMS was mostly induced by that rotation in both driver seat and passenger seat positions. The BrIC, thorax and abdominal injury values were close to each other between THOR and THUMS, while HIC15 and Acetabulum force values were different.

In the last decade, extensive efforts have been made to understand the physics of submarining and its consequences in terms of abdominal injuries. For that purpose, 27 Post Mortem Human Subject (PMHS) tests were performed in well controlled conditions on a sled and response corridors were provided to assess the biofidelity of dummies or human body models. All these efforts were based on the 50th percentile male. In parallel, efforts were initiated to transfer the understanding of submarining and the prediction criteria to the THOR dummies. Both the biofidelity targets and the criteria were scaled down from the 50th percentile male to the 5th percentile THOR female. The objective of this project was to run a set of reference PMHS tests in order to check the biofidelity of the THOR F05 in terms of submarining. Three series of tests were performed on nine PMHS, the first one was designed to avoid submarining, the second and third ones were designed to result in submarining.

Sled tests focused on pelvis behavior and submarining can be found in the literature. However, they were performed either with rigid seats or with commercial seats. The objective of this study was to get reference tests to assess the submarining ability of dummies in more realistic conditions than on rigid seat, but still in a repeatable and reproducible setup. For this purpose, a semi-rigid seat was developed, which mimics the behavior of real seats, although it is made of rigid plates and springs that are easy to reproduce and simulate with an FE model. In total, eight PMHS sled tests were performed on this semi-rigid seat to get data in two different configurations: first in a front seat configuration that was designed to prevent submarining, then in a rear seat configuration with adjusted spring stiffness to generate submarining. All subjects sustained extensive rib fractures from the shoulder belt loading.

Toyota Safety Sense is a safety system package developed to help drivers avoid accident types with a high frequency of occurrence. This paper deals with pre-collision system which forms the core of Toyota Safety Sense, especially Toyota Safety Sense P which uses a combined sensor configuration consisting of a monocular camera paired with millimeter wave radar, in order to achieve both high recognition performance and reliability. The use of a wide-angle monocular camera, millimeter wave radar integrated in the front grill emblem, and a collision determination algorithm for pedestrian targets enabled the development of a pre-collision system comprising detection capability of crossing pedestrians. Toyota has developed warning and pre-collision brake assist for driver to assist in avoiding a collision effectively; In addition, Pre-collision brake has achieved high level of performance for the drivers who cannot avoid a collision.

Many vehicles are currently equipped with active safety systems that can detect vulnerable road users like pedestrians and bicyclists, to mitigate associated conflicts with vehicles. With the advancements in technologies and algorithms, detailed motions of these targets, especially the limb motions, are being considered for improving the efficiency and reliability of object detection. Thus, it becomes important to understand these limb motions to support the design and evaluation of many vehicular safety systems. However in current literature, there is no agreement being reached on whether or not and how often these limbs move, especially at the most critical moments for potential crashes. In this study, a total of 832 pedestrian walking or cyclist biking cases were randomly selected from one large-scale naturalistic driving database containing 480,000 video segments with a total size of 94TB, and then the 832 video clips were analyzed focusing on their limb motions.

When a car collides against a pole-like obstacle, the deformation pattern of the vehicle body-side tends to extend to its upper region. A possible consequence is an increase of loading to the occupant thorax. Many studies have been conducted to understand human thoracic responses to lateral loading, and injury criteria have been developed based on the results. However, injury mechanisms, especially those of internal organs, are not well understood. A human body FE model was used in this study to simulate occupant kinematics in a pole side impact. Internal organ parts were introduced into the torso model, including their geometric features, material properties and connections with other tissues. The mechanical responses of the model were validated against PMHS data in the literature. Although injury criterion for each organ has not been established, pressure level and its changes can be estimated from the organ models.

Multi-dimensional code has been developed to simulate the effect of geometry on mass flow rate and flow pattern in the induction system of an internal combustion engine. The unsteady compressible Navier-Stokes equations in general curvilinear coordinates are solved by a new method of lines. In the method of lines, the governing equations are spatially discretized by a finite difference approximation and the resulting system of ordinary differential equations is integrated. As a time integration scheme, we newly propose to use the rational Runge-Kutta scheme in order to efficiently simulate the flows in the induction system. The domain-decomposition technique is introduced so that body-fitted structured grid can be easily generated for such complex geometry as a real intake port shape. The present code is applied to 2 and 3 dimensional steady flows in intake port/cylinder assembly with a valve.