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Technical Paper

Frequency-based substructuring for virtual prediction and uncertainty quantification of thin-walled vehicle seat structures

2024-06-12
2024-01-2946
Finite element simulation (FE) makes it possible to analyze the structural dynamic behavior of vehicle seat structures in early design phases to meet Noise-Vibration-Harshness (NVH) requirements. For this purpose, linear simulations are usually used, which neglect many nonlinear mechanical properties of the real structure. These models are trimmed to fit global vibration behavior based on the complex description of contact or jointed definitions. Targeted design is therefore only possible to a limited extent. The aim of this work is to characterize the entire seat structure and its sub-components in order to identify the main contributors using experimental and simulative data. The Lagrange Multiplier Frequency Based Substructuring (LM-FBS) method is used for this purpose. Therefore, the individual subsystems of seat frame, seat backrest and headrest are characterized under different conditions.
Technical Paper

Dummy Positioning at Reclined Seating Position before Impact Testing

2024-04-09
2024-01-2490
Alongside advancements in automated vehicle technologies, occupants within vehicle compartments are enjoying increased freedom to relax and enjoy their journeys. For instance, reclined seating postures have become more prevalent and comfortable compared to upright seating when Highly Automated Vehicles (HAVs) are introduced. Unfortunately, most Anthropomorphic Testing Devices (ATD) do not support reclined postures. THOR-AV 50M is a specially designed dummy for reclined postures. As a crucial tool for developing safety restraint systems to protect reclined occupants, the first question is how to position it correctly on a reclined seat before impact testing. In this study, classical zero gravity seats were selected. H-point coordinators of selected seat at 25°, 40° and 60° seatback angle were measured and compared by using H-point machine (HPM) even though current HPM was not designed for reclined seat.
Technical Paper

Unique curved based seat design for better ride comfort

2024-04-09
2024-01-2507
Designing an automotive seat, it is required to perform a detailed study of anthropometry, which deals with measurement of human individuals and understanding human physical variations. It also requires application-based movement study of driver’s hands, feet’s & overall body movement. It is very difficult to design seat curvatures based on any static manikin-based software. We at VECV, have developed a new concept using mixed reality VR technology to capture all body movements for designing best in class seat curvature to accommodate variety of drivers with different body types. We have designed a specialized static bunk, which has a wide range of seat, steering and ABC paddle adjustments, which are integrated with virtual data. We use to study and capture the data of driving position and other ergonomic postures of wide range of people with different body types on this static bunk according to their comfortable driving posture.
Technical Paper

Vehicle Seat Occupancy Detection and Classification Using Capacitive Sensing

2024-04-09
2024-01-2508
Improving passenger safety inside vehicle cabins requires continuously monitoring vehicle seat occupancy statuses. Monitoring a vehicle seat’s occupancy status includes detecting if the seat is occupied and classifying the seat’s occupancy type. This paper introduces an innovative non-intrusive technique that employs capacitive sensing and an occupancy classifier to monitor a vehicle seat’s occupancy status. Capacitive sensing is facilitated by a meticulously constructed capacitance-sensing mat that easily integrates with any vehicle seat. When a passenger or an inanimate object occupies a vehicle seat equipped with the mat, they will induce variations in the mat’s internal capacitances. The variations are, in turn, represented pictorially as grayscale capacitance-sensing images (CSI), which yield the feature vectors the classifier requires to classify the seat’s occupancy type.
Technical Paper

Comparison of the Responses of the Thorax and Pelvis of the GHBMC M50 -O Using Two Different Foam Materials in a High-Speed Rear Facing Frontal Impact Scenario

2024-04-09
2024-01-2647
Due to the lack of biofidelity seen in GHBMC M50-O in rear-facing impact simulations involving interaction with the seat back in an OEM seat, it is important to explore how the boundary conditions might be affecting the biofidelity and potentially formulate methods to improve biofidelity of different occupant models in the future while also maintaining seat validity. This study investigated the influence of one such boundary condition, which is the seat back foam material properties, on the thorax and pelvis kinematics and injury outcomes of the GHBMC 50th M50-O model in a high-speed rear-facing frontal impact scenario, which involves severe occupant loading of the seat back. Two different seat back foam materials were used – a stiff foam with high densification and a soft foam with low densification. The peak magnitudes of the T-spine resultant accelerations of the GHBMC M50-O increased with the use of soft foam as compared to stiff foam.
Technical Paper

Analysis of Occupants by Seating Location, Restraint Use and Injury Risk in Tow-Away Crashes

2024-04-09
2024-01-2752
This study was conducted to assess the occupant restraint use and injury risks by seating position. The results were used to discuss the merit of selected warning systems. The 1989-2015 NASS-CDS and 2017-2021 CISS data were analyzed for light vehicles in all, frontal and rear tow-away crashes. The differences in serious injury risk (MAIS 3+F) were determined for front and rear seating positions, including the right, middle and left second-row seats. Occupancy and restraint use were determined by model year groups. Occupancy relative to the driver was 27% in the right-front (RF) and 17% in the second row in all crashes. About 39% of second-row passengers were in the left seat, 15% in the center seat and 47% in the right seat. Restraint use was lower in the second row compared to front seats. It was 43% in the right-front and 32% in the second-row seats in all crashes involving serious injury. Restraint use increased with model year groups.
Technical Paper

Compatibility Between Vehicle Seating Environments and Load Legs on Child Restraint Systems (CRS)

2024-04-09
2024-01-2751
Load legs on child restraint systems (CRS) protect pediatric occupants by bracing the CRS against the floor of the vehicle. Load legs reduce forward motion and help manage the energy of the CRS during a crash. As more CRS manufacturers in the United States (US) consider incorporating these safety features into their products, benchmark data are needed to guide their design and usage. The objective of this study is to develop benchmark geometrical data from both CRS and vehicle environments to help manufacturers to incorporate compatible load legs into the US market. A sample of vehicle environments (n=104 seating positions from n=51 vehicles, model years 2015 to 2022) and CRS with load legs (n=10) were surveyed. Relevant measurements were taken from each sample set to compile benchmark datasets. Corresponding dimensions were compared to assess where incompatibilities might occur.
Technical Paper

An Assessment of the Tesla Model 3's Forward Collision Warning and Automatic Emergency Braking Systems against a Stationary Pedestrian Target

2024-04-09
2024-01-2482
A total of 93 tests were conducted in daytime conditions to evaluate the effect on the Time to Collision (TTC), emergency braking, and avoidance rates of the Forward Collision Warning (FCW) and Automatic Emergency Braking (AEB) provided by a 2022 Tesla Model 3 against a 4ActivePA adult static pedestrian target. Variables that were evaluated included the vehicle speed on approach, pedestrian offsets, pedestrian clothing, and user-selected FCW settings. As a part of the Tesla’s Collision Avoidance AssistTM, these user-selected FCW settings change the timing of the issuance of the visual and/or audible warning provided. This testing evaluated the Tesla at speeds of 25 and 35 miles per hour (mph) versus a stationary pedestrian target in early, medium, and late FCW settings. Testing was also conducted with a 50% pedestrian offset and 75% offset conditions relative to the right side of the Tesla.
Journal Article

Assessing the Impact of Rubberized Asphalt on Reducing Hip Fracture Risk in Elderly Populations Using Human Body Models

2024-04-08
Abstract Compared to other age groups, older adults are at more significant risk of hip fracture when they fall. In addition to the higher risk of falls for the elderly, fear of falls can reduce this population’s outdoor activity. Various preventive solutions have been proposed to reduce the risk of hip fractures ranging from wearable hip protectors to indoor flooring systems. A previously developed rubberized asphalt mixture demonstrated the potential to reduce the risk of head injury. In the current study, the capability of the rubberized asphalt sample was evaluated for the risk of hip fracture for an average elderly male and an average elderly female. A previously developed human body model was positioned in a fall configuration that would give the highest impact forces toward regular asphalt.
Standard

SAE Child Passenger Safety Glossary

2024-03-01
CURRENT
J2939_202403
To harmonize and define terminology associated with occupant protection for children for vehicle manufacturers and child restraint manufacturers in the United States and Canada.
Technical Paper

Evaluation of Lightweight Cotton Textiles for Durable and Comfortable Automotive Interior Applications

2024-02-06
2024-01-5015
In regions with hot and humid climatic conditions, lightweight cotton textiles such as lawns, are famous for clothing and being explored for use in automobile interiors. Specifically, there’s an interest in these fabrics for car seat covers, interior roof linings, and door trims. Textiles must balance weight and durability for automotive applications to ensure passenger comfort while withstanding regular wear and tear. This study assesses cotton fabrics’ wear and mechanical performance with densities between 40 and 60 g/m2, produced using yarn counts of 70, 60, and 40 Ne. The objective was to determine the optimal fabric parameters for creating automotive spare parts that are both durable and comfortable. Two production strategies were contrasted: coarser yarn counts with fewer warp and weft threads per inch and finer yarn counts with a higher thread density.
Technical Paper

Effect of Stacking Sequence on Mechanical Properties of Bamboo/Bagasse Composite Fiber for Automobile Seat Cushions and Upholstery Application

2024-02-06
2024-01-5013
Researchers have chosen to study natural fibers instead of synthetic fibers since low-cost and ecologically favorable materials are required. The present research concentrates on the mechanical characteristics of epoxy composites reinforced with bamboo and bagasse fibers. The hybrids were created using four different ratios of bamboo/bagasse fibers, then hand-laid up. The material characteristics of the generated composites, including tension, bending, impacts, and Shore D hardness measurements, were assessed. The scanning electron microscopy technique was used to study morphology. Three levels of bamboo and a core network of bamboo fibers in composites were assumed to generate superior qualities. The core layer of bamboo and an outer layer typically characterized by sugarcane composites have enhanced flexural strength and Shore D toughness because of the bamboo layer at the center.
Standard

Sensor Driven Restraint Systems

2024-01-26
WIP
AS7260
• AIRBAG COMPONENT MINIMUM PERFORMANCE REQUIREMENTS • AIRBAG INSTALLATION PERFORMANCE REQUIREMENT Current revision will only contain Part 25 and lapbelt installed airbags. Future revisions will expand to include Structural airbags, 3-point restraint airbag, pre-tensioner etc.
Technical Paper

Investigation of Mechanical and Thermal Properties of Bamboo Fiber Reinforced with Epoxidized Soybean Oil for Automotive Seat Bases

2024-01-22
2024-01-5009
Bamboo fibers were used as reinforcement in hardened epoxy mixes altered with ethoxylated soybean oil (ESO) to enhance the mechanical and thermal qualities. Compared to a bio-based epoxy mix, the tensile strength and modulus of the laminate with 20% bamboo fiber were higher. During thermogravity analysis (TGA) evaluation, it was discovered that the rate of deterioration peak had been moved to a warmer temperature, indicating improved thermal durability of the aggregate over the base material. The dynamic mechanical evaluation of the bio-based composite anticipated increased storage modulus and greater glass transition temperatures. High fiber–matrix adherence was visible in scanning electron morphology (SEM). Measurements of the interfacial adhesion demonstrate the hydrophilicity of the bio-based reinforced composites. The binding and effective insemination of fibers is responsible for the fiber-reinforced composite’s durability.
Standard

Ambulance Patient Compartment Seated Occupant Excursion Zone Evaluation

2024-01-19
CURRENT
J3059_202401
This SAE Information Report describes the testing and reporting procedures that may be used to evaluate and document the excursion of a worker or civilian when transported in a seated and restrained position in the patient compartment of a ground ambulance when exposed to a front, side, or rear impact. Its purpose is to provide seating and occupant restraint manufacturers, ambulance builders, and end-users with testing procedures and documentation methods needed to identify head travel paths in crash loading events. This is a component level test. The seating system is tested in free space to measure maximum head travel paths. The purpose is not to identify stay out zones. Rather, the goal is to provide ambulance manufacturers with the data needed to design safer and functionally sound workstations for Emergency Medical Service workers so that workers are better able to safely perform patient care tasks in a moving ambulance.
Technical Paper

Study and Analysis of Dynamic Seat Pressure Distribution by Human Subjects during Vehicle Running State on Test Tracks

2024-01-16
2024-26-0354
The purpose of this study is to conduct dynamic seat pressure mapping on vehicle seats during its operation on different test tracks under ambient environmental conditions for a defined speed. The test track comprises of pave roads, high frequency track, low frequency track and twist track. The variations in pressure distribution on seat during diverse road load inputs help to understand the seat cushion and back comfort for unique percentiles of human subjects ranging from 50th to 95th percentile population. For conducting the study, a sport utility vehicle (SUV) loaded with leatherette seats has chosen. Totally six participants (human subjects), five male and one female selected for the study based on their BMI (Body mass index) and body morphology. Pressure mats suitable for taking dynamic load inputs and able to log the data at a defined sampling rate mounted on seats and secured properly. The pressure mats should cover the seat cushion, bolster areas and back seat completely.
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