Iron (Fe) nano-polycrystalline metal obtained by sintering reduced iron nanoparticles from iron oxide was applied to an axial flux generator. When the thickness of the core material is 1/10, it has ...the same ability of the power generation as when Fe bulk is used as the core. We can also reduce the iron loss (hysteresis loss and eddy current loss), which enables the construction of thin and axial flux generators with light weight. We investigated the magnetization property of the core inductor at the direct current and found that Fe nanoparticles were produced from iron oxide particles by high voltage pulse or laser ablation in liquids. Core inductors with these materials were fabricated. It has been clarified from measurements of the core inductor magnetization that the relative permeability of the sintered Fe nanopolycrystalline was one million.
This paper describes the reconstructions of pedestrian accidents colliding with the SUV (Sport Utility Vehicle) type vehicle. The finite element human model of American male 50 percentile is used to ...evaluate the kinematics and injuries of the lower leg. The finite element models of the frontal structures made of urethane blocks that have equivalent stiffness to the frontal structure of the SUV finite element model were established to conduct parametric studies of the frontal structure stiffness. The parametric studies show optimum stiffness distributions of the urethane blocks to help reduction of the knee-bending angle and injuries.
This paper describes the new finite element modelling method of aluminium honeycomb using shell elements. It is our new modelling method in which the cell size of the honeycomb structure is enlarged ...to increase minimum mesh size, and compressive strength is controlled by thickness of shell elements. New modelling was applied to an offset deformable barrier (ODB) model and a full vehicle crash analysis was performed. The result of offset frontal collision analysis with a new honeycomb model showed better correlation with the test result than the result of previous simulations.
Recent titanium oxide nanotube arrays have attracted attention for their applications. Titanium oxide nanotubes were prepared under potentiostat conditions (10 – 60 V) for various times (1 min – 3 ...hr). SEM observations revealed that the pore sizes of the nanotubes have a tendency to increase with an increase in the applied potential in the NH4F-glycerol-H2O electrolyte. Some corrosive pores were observed on the surface of titanium substrate at 40 V for 1 minute at 40°C. The pores covered the surface of the titanium substrate after 10 minutes, and some small pores were observed in the inner part of the pores, which should correspond to the combining of some small adjacent pores into a large one. The combining of the tubes were observed after 2 h and 3 h anodization times, and the nanotube arrays seem to be formed upward from the SEM side-views. The photocatalytic activity of the titanium oxide nanotubes was evaluated according to the JIS standard (JIS R 1703–2). The R factor of the titanium oxide nanotube arrays formed at 40 V and 40°C for a 3h the anodization time was 9.71 n mol/l·min, which was twice that of the titanium oxide thin film obtained by the rf-sputtering method.
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. Strain based indicators were used in the simulation model to estimate skeletal injury (bony fracture) and soft tissue (brain and internal organs) injury. The study results primarily showed that the injury risk became higher with the collision speed, but was also affected by the combination of the factors such as the pedestrian size and the impact location. The study also discussed the injury patterns and trends with respect to the factors examined. In all of the simulated conditions, the model did not predict any severe injury at a collision speed of 20 km/h.
This article describes the reconstructions of pedestrian accidents of several sizes and human genders colliding with sedan-type vehicles. Finite element (FE) human models of American male 50 ...percentile, American female 5 percentile, and 6-year old child are used to evaluate the lower leg kinematics and injuries to them. FE models of the frontal structures made of urethane blocks that have equivalent stiffness to the frontal structure of the sedan FE model were established to conduct parametric studies of frontal structure stiffness. The parametric studies show optimum stiffness distributions of urethane blocks to help reduce the knee-bending angle and injuries.
The WorldSID dummy can be equipped with both a pubic and a sacroiliac joint (S-I joint) loadcell. Although a pubic force criterion and the associated injury risk curve are currently available and ...used in regulation (ECE95, FMVSS214), as of today injury mechanisms, injury criteria, and injury assessment reference values are not available for the sacroiliac joint itself. The aim of this study was to investigate the sacroiliac joint injury mechanism. Three configurations were identified from full-scale car crashes conducted with the WorldSID 50th percentile male where the force passing through the pubis in all three tests was approximately 1500 N while the sacroiliac Fy/Mx peak values were 4500 N/50 Nm, 2400 N/130 Nm, and 5300 N/150 Nm, respectively. These tests were reproduced using a 150 kg guided probe impacting Post Mortem Human Subjects (PMHS) at 8 m/s, 5.4 m/s and 7.5 m/s. The shape and the orientation of the impacting face of the probe were selected to match the WorldSID pubic Fy and sacroiliac Fy/Mx loads of the three vehicle test configurations. Three PMHS were tested in each of the three configurations (nine PMHS in total).
In the first PMHS configuration, one specimen sustained an AIS 3 injury and one sustained an AIS 4 injury (an unstable pelvis with complete disruption of the posterior arch, a sacroiliac joint disruption associated with an iliac fracture, and a pubic symphysis separation). In the second configuration, all specimens sustained a fracture of the superior lateral iliac wing (AIS 2). In the third configuration, one specimen sustained a partial disruption of the anterior arch (AIS 2). Based on the data from strain gauges located on the pubic rami and near the sacroiliac joint, the pubic rami fractures were identified as occurring prior to the sacroiliac fractures.
Out of nine impactor tests performed, the PMHS S-I joint injuries were observed to consistently be associated with pelvic anterior arch fractures. In addition, from the injury sequences derived from strain gauges located on the specimen pelvises and on the injury assessments obtained by necropsy, the S-I joint fractures were observed to occur after the anterior arch fractures.
Objectives: The objective of this study is to examine the effectiveness of the active head restraint system in reducing neck injury risk of car occupants in low-speed rear impacts.
Methods: A human ...body FE model "THUMS" was used to simulate head and neck kinematics of the occupant and to evaluate loading to the neck. Joint capsule strain was calculated to predict neck injury risk as well as NIC. The validity of the model was confirmed comparing its mechanical responses to those in human subjects in the literatures. Seat FE models were also prepared representing one with a fixed head restraint and the other one with an active head restraint system. The active head restraint system was designed to move the head restraint forward and upward when the lower unit was lower unit was loaded by the pelvis. Rear impact simulations were performed assuming a triangular acceleration pulse at a delta-V of 25 km/h.
Results
: The model reproduced similar head and neck motions to those measured in the human volunteer test, except for active muscular responses. The calculated joint capsule strain also showed a good match with those of PMHS tests in the literature. A rear-impact simulation was conducted using the model with the fixed head restraint. The result revealed that NIC was strongly correlated with the relative acceleration between the head and the torso and that its maximum peak appeared when the head contacted the head restraint. It was also found that joint capsule strain grew in later timing synchronizing with the relative displacement. Another simulation with the active head restraint system showed that both NIC and joint capsule strain were lowered owing to the forward and upward motion of the head restraint. A close investigation of the vertebral motion indicated that the active head restraint reduced the magnitude of shear deformation in the facet joint, which contributed to the strain growth in the fixed head restraint case.
Conclusions: Rear-impact simulations were conducted using a human body FE model, THUMS, representing an average-size male occupant. The cervical system including the facet joint capsules was incorporated to the model. The validity of the model was examined comparing its mechanical responses to those in the literature such as the whole body motion of the volunteer subject and the vertebral motion in the PMHS tests. Rear-impact simulations were conducted using the validated THUMS model and two prototype seat models; one had a fixed head restraint and the other one was equipped with an active head restraint system. The active head restraint system works moving the head restraint forward and upward when the lower unit is loaded by the pelvis. The head and neck kinematics and responses were analyzed from the simulation results. The force and acceleration rose at the pelvis first, followed by T1 and the head. The early timing of force rise and its magnitude indicated that the pelvis force was a good trigger for the active head restraint system. The results showed that the head was supported earlier in a case with the active head restraint system, and both NIC and joint capsule strain were lowered. The study also analyzed the mechanism of strain growth in the joint capsules. Relatively greater strain was observed in the direction of the facet joint surface, which was around 45 degrees inclined to the spinal column. The forward and upward motion of the active head restraint were aligned with the direction of the joint deformation and contributed to lower strain in the joint capsules. The results indicated that the active head restraint could help reduce the neck injury risk not only by supporting the head at an early timing but also through its trajectory stopping the joint deformation.
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. Finite element simulations were conducted assuming a case where a passenger vehicle collides against a pole at 29km/h. Occupant kinematics, force-deformation responses and pressure levels were compared between cases with and without side airbag deployment. The results indicated that strain to the ribs and pressure to the organs was smaller with side airbag deployment. The side airbag widened the contact area at the torso, helping to distribute the force to the shoulder, arm and chest. Such distributed force helped generate relatively smaller deformation in the ribs. Furthermore, the side airbag deployment helped restrict the spine displacement. The smaller displacement contributed to lowering the magnitude of contact force between the torso and the door. The study also examined the correlations between the pressure levels in the internal organs, rib deflection, and V*C of chest. The study found that the V*C(t) peak appeared to be synchronized with the organ pressure peak, suggesting that the pressure level of the internal organs could be one possible indicator to estimate their injury risk.
