This paper deals the verification & Validation of passenger seat of buses for life cycle requirement. Through various methodologies adopted from Data collection, CAE verification and physical validation to verify the seat in virtual environment. Generally it is observed that in City Buses most of the time Passenger seat leg mounting area failures occurs in buses used for typically more than 3years. This fatigue failure doesn't get captured in either Anchorage test or limited vibration test. Passenger seats durability should be equal to vehicle life which is 10L or 12 Years of life span. Testing on Physical vibration (Rig) machine is time consuming and costly most of the time Machine availability for testing will be an issue to validate alternate seat proposals. There is need to establish a correlation between Physical testing and CAE simulation so that alternate proposals can be easily and quickly verified using CAE alone.
This SAE Recommended Practice describes two-dimensional 95th percentile truck driver side view, seated stomach contours for horizontally adjustable seats (see Figure 1). There is one contour and three locating lines to accommodate male-to-female ratios of 50:50, 75:25, and 90:10 to 95:5.
This SAE Recommended Practice describes two-dimensional, 95th percentile truck driver, side view, seated shin-knee contours for both the accelerator operating leg and the clutch operating leg for horizontally adjustable seats (see Figure 1). There is one contour for the clutch shin-knee and one contour for the accelerator shin-knee. There are three locating equations for each curve to accommodate male-to-female ratios of 50:50, 75:25, and 90:10 to 95:5.
This recommended practice is a source of information for body and trim engineers and represents existing technology in the field of on-highway vehicle seating systems. It provides a more uniform system of nomenclature, definitions of functional requirements, and testing methods of various material components of motor vehicle seating systems.
Define and develop test parameters, test methods, measurements, and acceptable performance criteria for composite aircraft seat structures.
2015 engines ride a technology tidal wave Powertrain engineers are diving deeper to find new ways to make light-duty power units more efficient without compromising performance. Connectivity for comfort Seat suppliers such as Continental, Johnson Controls, and Faurecia pursue 'networked' seats to enhance safety, personalization, and comfort. Assembling aluminum vehicles in volume Ford's 2015 F-150 pickup pioneers high-volume mass-production of lightweight aluminum car and truck structures.
This SAE Aerospace Recommended Practice (ARP) documents a common understanding of terms, compliance issues and occupant injury criteria to facilitate certification of oblique facing seat installations specific to Part 25 aircraft.
This SAE Recommended Practice specifies performance requirements and test procedures for the strength and location of seat belt assembly anchorages. It applies to seat belt anchorages attached to vehicle body structure or to seat assemblies in the vehicle. Design Considerations are specified in SAE J383.
Abstract The automotive industry needs sustainable seating products which offer good climate performance and superior seating comfort. The safety requirement is always a concern for current seating systems. The life of the present seating system is low and absorbs moisture over a period of time which affects seat performance (cushioning effect). Recycling is one of the major concerns as far as polyurethane (PU) is concerned. This paper presents the development of an alternative material which is eco-friendly and light in weight. Thermoplastic Polyolefin (PO) materials were tried in place PU for many good reasons. It is closed cell foam which has better tear and abrasion resistance. It doesn't absorb water and has excellent weathering resistance. Also it has a better cushioning effect and available in various colours. Because of superior tear resistance, it is possible to eliminate upholstery and would reduce system level cost.
This recommended practice describes boundaries of hand control locations that can be reached by a percentage of different driver populations in passenger cars, multi-purpose passenger vehicles, and light trucks (Class A vehicles). This practice is not applicable to heavy trucks (Class B vehicles).
Methods will be developed to characterize In Flight Entertainment (IFE) component impact performance separate from seat design. These methods will address both initial seat head impact criterion (HIC) testing and subsequent IFE component changes. Methods will evaluate head blunt trauma, post-impact sharp edges, and egress impediment. Criteria development will involve defining test methods, test parameters, measurements, and acceptance criteria. Particular emphasis on evaluating IFE changes that require coordination and evaluation per SAE ARP 6448, Appendix B.
This document provides informational background, rationale and a technical case to allow consideration of the removal of the magnesium alloy restriction in aircraft seat construction as contained in AS8049B. The foundation of this argument is flammability characterization work performed by the FAA at the William J. Hughes Technical Center (FAATC), Fire Safety Branch in Atlantic City, New Jersey, USA. The rationale and detailed testing results are presented along with flammability reports that have concluded that the use of specific types of magnesium alloys in aircraft seat construction does not increase the hazard level potential in the passenger cabin in a post-crash fire scenario. Further, the FAA has developed a lab scale test method, reference DOT/FAA/TC-13/52, to be used as a certification test, or method of compliance (MOC) to allow acceptability of the use of magnesium in the governing TSO-C127 and TSO-C39C.
This SAE Aerospace Recommended Practice (ARP) provides guidance for the design and location of flight attendant stations, including emergency equipment installations at or near such stations, so as to enable the flight attendant to function effectively in emergency situations, including emergency evacuations. Recommendations regarding design of flight attendant stations apply to all such stations; recommendations regarding location apply to those stations located near or adjacent to floor level exits.
This SAE Recommended Practice encompasses the significant factors which determine the effectiveness of a seat system in limiting spinal injury during vertical impacts between the rider and the snowmobile seat system. The document is intended to provide a tool for the development of safer snowmobile seats. It is recognized that the seat is only a portion of the entire vehicle protective suspension system. It is, however, usually required that the seat serve as added protection to the suspension system, since the latter may "bottom out" during a severe impact. The term "seat" refers to the occupant-supporting system not normally considered part of the vehicle suspension or frame system. In some cases, it may include more than the foam cushion.
Abstract Seating comfort is one of the most important indicators of the performance of automotive seats. The objective and subjective evaluation of seating comfort plays an important role in the development of seating systems. Objective methods are primarily based on evaluating the influence of vibrations on the driver's seat and assessing the seat pressure ratio. The primary goal of this study was to evaluate the comfort of two car seats (sedan and compact) by comparing a subjective technique with an objective technique like body pressure ratio for a sample of 12 subjects. The results show that the pressure ratio for IT (ischial tuberosity) and L4/L5 were significantly greater for the seat of a compact car than the seat of a sedan car. The subjective comfort was significantly greater for the seat of the sedan car and females than the seat of the compact car and males, respectively.
Abstract Vibration is both a source of discomfort and a possible risk to human health. There have been numerous studies and knowledge exists regarding the vibrational behavior of vehicle seats on adult human occupants. Children are more and more becoming regular passengers in the vehicle. However, very little knowledge available regarding the vibrational behavior of child safety seats for children. Therefore, the objective of this study was to measure the vibrations in three different baby car seats and to compare these to the vibrations at the interface between the driver and the automobile seat. The test was performed on the National road at the average speed of 70 km/h and acceleration levels were recorded for about 350 Sec (5.83 min). One male driver considered as an adult occupant and a dummy having a mass of 9 kg was representing one year old baby. Four accelerometers were used to measure the vibration. All measured accelerations were relative to the vertical direction.
A Consumer Utility Model of Automotive Seating Comfort: Discomfort, Comfort Character, and Expectations
Abstract Experience tells us that one can develop a technically comfortable seat where the seat fits and supports the occupant. The pressure distribution is optimized and the seat and packaging are such that a good posture is attainable by many. The dynamic characteristics of the seat and the vehicle are technically good. Despite all this the customer is not satisfied. Despite it being a technically comfortable seat, it does meet the customers' expectations and/or priorities and thus the comfort provided is lacking. This paper seeks to explore that gap between the seat and the user by modeling comfort using techniques similar to those found in the social sciences where models often focus on user or individual behavior. The model is built upon but diverges from the Cobb Douglas consumer utility model found in economics. It is presented as theory and presents a very different perspective on comfort.
Abstract Seat comfort is an important factor in the development of a vehicle; however, comfort can be measured in many ways. Many aspects of the experimental design such as the duration of the drive test, the questions asked, and the make-up of the test subjects are known to influence comfort results. This paper provides the background methodology and results of a Seat comfort study aimed at assessing long-term driving seat comfort.
Flexible polyurethane (PU) foam has been widely used for seat cushions in automotive passenger vehicles due to the excellent cushioning performance and the ability to shape mold. Originally introduced in the late 1950's, it has been used for more than 50 years. However, there is a limitation using polyurethane foam with efforts to reduce the weight and address ever increasing risks to environment. This paper provides information about a new automotive seat concept which does not use polyurethane foam at all. Expanded polyolefin foam is used for this application to replace polyurethane foam and achieve comparable cushioning performance. Other features of the material include 100% recyclability, and no VOC's. By replacing polyurethane foam with expanded thermoplastic foam, hazardous outgassing is eliminated during the seat cushion production, thus improving workplace environmental health and safety.
Abstract In terms of the responsive quality of cars, reducing the vibration of car seats is very important, as this vibration is transmitted directly to the driver. Here, a sensitivity analysis method was used to reasonably reduce the vibration of car seats at minimal cost. A laboratory test was conducted under two excitation conditions: first, vibration in idle state; second, random vibration not exceeding 100 Hz. To determine the reliability of the laboratory test, the actual vibration in idle state was simulated in a multi-axial simulation table for the idle excitation environment of cars that are sensitive to even the smallest changes in the environment. The frequencies of interest were selected by adding the sums of frequency response functions measured at the 24 nodal points of interest under the two excitation conditions.
In vehicle driving environment, the driver is subjected to the vibrations in horizontal, vertical, and fore-aft directions. The human body is very much sensitive to whole body vibration and this vibration transmission to the body depends upon various factors including road irregularities, vehicle suspension, vehicle dynamics, tires, seat design and the human body's properties. The seat design plays a vital role in the vibration isolation as it is directly in contact with human body. Vibration isolation properties of a seat depend upon its dynamic parameters which include spring stiffness and damping of seat suspension and cushion. In this paper, an optimization-based method is used to determine the optimal seat dynamic parameters for seat suspension, and cushion based on minimizing occupant's body fatigue (occupant body absorbed power). A 14-degree of freedom (DOF) multibody biodynamic human model in 2D is selected from literature to assess three types of seat arrangements.
Estimation of Nonlinear Viscoelastic Parameters from Estimated Linear Models of Behavior around Multiple Settling Points of a Foam-Mass System
Flexible polyurethane foam is the main cushioning element used in car seats. Optimization of an occupied seat's static and dynamic behavior requires models of foam that are accurate over a wide range of excitation and pre-compression conditions. In this research, a method is described to estimate the parameters of a global model of the foam behavior from data gathered in a series of impulse tests at different settling points. The estimated model is capable of describing the responses gathered from all the impulse tests using a unique set of parameters. The global model structure includes a nonlinear elastic term and a hereditary viscoelastic term. The model can be used to predict the settling point for each mass used and, by expanding the model about that settling point, local linear models of the response to impulsive excitation can be derived. From this analysis the relationship between the local linear model parameters and the global model parameters is defined.
Research on Driving Posture Comfort Based on Relation between Drivers' Joint Angles and Joint Torques
Driving comfort is one of the most important indexes for automobile comfort. Driving posture comfort is closely related to the drivers' joint angles and joint torques. In present research, a new method is proposed to identify the most comfortable driving posture based on studying the relation between drivers' joint angles and joint torques. In order to truly reflect a driving situation, the accurate human driving model of 50 percent of the size of Chinese male is established according to the human body database of RAMSIS firstly. Biomechanical model based on accurate human driving model is also developed to analyze and obtain dynamic equations of human driving model by employing Kane method. The joint torque-angle curves of drivers' upper and lower limbs during holding wheel or pedal operation can be obtained through dynamic simulation in the MATLAB. Through curve-fitting analysis, the minimum joint torque of a driver' limb and the optimal joint angel can be found.
The suspension system of a heavy truck's driver seat plays an important role to reduce the vibrations transmitted to the seat occupant from the cab floor. Air-spring is widely used in the seat suspension system, for the reason that its spring rate is variable and it can make the seat suspension system keep constant ‘tuned’ frequency compared to the conventional coil spring. In this paper, vibration differential equation of air-spring system with auxiliary volume is derived, according to the theory of thermodynamic, hydrodynamics. The deformation-load static characteristic curves of air-spring is obtained, by using a numerical solution method. Then, the ADAMS model of the heavy truck's driver seat suspension system is built up, based on the structure of the seat and parameters of the air-spring and the shock-absorber. At last, the model is validated by comparing the simulation results and the test results, considering the seat acceleration PSD and RMS value.
Comfort is a main factor in customer's decision when buying a car. The seat plays a very important role, as it is the interface between occupant and vehicle. Pressure distribution is today's most common approach to characterize seat comfort, but it shows limitations. Analysis of human inter-tissue stress tends to be relevant for an objective comfort assessment. This paper presents the construction and validation of a CAE human model, based on Magnetic Resonance Imaging scans and in-vivo tests data. Correlation between objective criteria and subjective evaluation will be investigated, comfort performance of a real seat will be predicted.
Vehicle floor vibration is the resultant of different road inputs damped through various transfer paths. Seat comfort, which depends on these floor vibrations, can be evaluated with a single input signal “Pink noise”; which constitutes various road inputs. Transmissibility of seat structure on a vibration shaker with pink noise input includes all possible responses of road inputs. Still, transmissibility profile at vehicle end and component level varies. This is due to the utilization of “dummy” on component level testing on vibration shaker, which acts as a dead weight with dissimilar damping characteristics of human. A transmissibility correlation between human and dummy is attained by replacing the dummy in place of human and actuating it to find the difference in contribution between them for different class of vehicles. This contribution extrapolation from the damping effects of human and dummy is applied on dummy transmissibility.
The Contribution of the Local Product Engineering in the Search for Innovative Modular Solutions: A Case Study of the Front Seat Structure
A frequent situation in the national automobile industry is the each time bigger rapidity that just-launched models are evolved (the so called face-lifts). Within this highly dynamic context, the solutions and technical proposals developed by the local product engineering have two main guidelines. The first one is to work on product evolutions which goal is to make the vehicles far more attractive and differentiated with respect to the competition and also to the previous model. The second one is to constantly search the standardization or the modularization of parts between the different models and versions of vehicles, thus reducing the costs of investments and providing scale profits.
Development of a Methodology Focused on the Improvement of Both: Ergonomics and Comfort of Commercial Vehicle Seats
Safety, Ergonomics and comfort are inseparable concepts and of greater relevance to the full exercise of professional drivers, being the seat, one of the most important components to be considered, when designing their workplace. This work presents initiatives taken by Mercedes-Benz do Brasil Ltda. (MBBras) in partnership with GRAMMER do Brasil Ltda. (Grammer) and Oficio Ergonomia e Design Ltda. concerning the improvement of a SAE Class 8 Heavy-truck Driver Seat. Proposals involved seat design improvement at driver reach and posture, design and constructive characteristics (seat-bottom foam and frame) Upholstery, seat-controls ergonomics and the vibration response, due to the introduction of independent shock-absorbers.
Seating solutions steer toward steel Zoomy-looking designs and alternative materials are eye-catching and save weight, but steel keeps getting lighter.
Seats and seating