Seat Back Research Articles

Design for Headrest Including Guides Slot to Reduce the Neck Force in Rear End Impact

Whiplash injuries are one of the most common injuries reported in automotive rear end collisions. Automobile seat back and head restraints play a role in reducing neck injuries during low speed rear end collisions. Currently, many studies are being conducted on ways to reduce neck injuries. These deal with the design parameters that cause neck injuries and do not address the design of the head restraint connection structure. In this paper, we analyze the various trajectories of the headrest and propose a new design for a connection structure that can move along the corresponding trajectory. We model the headrest connection mechanism as a virtual link using kinematic modeling and perform trajectory analysis. Using the trajectory of motion, we select an oblong shape for the guide slot by fitting it with the equation of an ellipse and propose a new headrest connection mechanism. To evaluate the design of the proposed mechanism, we model the shape of the mechanism and test it using dynamic simulation under collision conditions. In addition, we design a prototype for the proposed guide, conduct a sled test, and confirm that the neck force is reduced by the proposed connection structure. In the proposed structure, the values of maximum upper neck shear and tension decreased by more than 20 % compared to existing headrest.

Driver head locations: Considerations for head restraint design

Objective: U.S. FMVSS 202a requires that a vehicle head restraint lie within a specified distance (55 mm) from the physical headform on the head restraint measurement device (HRMD). Smaller values of this distance, known as backset, are frequently associated with improved protection against neck injury in rear impact. In some vehicles, small backsets are also associated with complaints of head restraint interference with drivers’ preferred head positions. The objective of this study is to examine head/head restraint distances using data from a lab study of driving posture to provide guidance for safe and comfortable head restraint design.Methods: Head positions were measured for 88 U.S. drivers in a laboratory mockup using a seat from a mid-size sedan. The head restraint was removed to allow measurement of drivers’ preferred head locations without interference from the head restraint. Rates of disaccommodation, defined as interference between predicted possible head restraint locations and drivers’ preferred head locations, were analyzed at HRMD-referenced backsets of 25, 50, 75, and 100 mm measured at 22° and 25° seat back angles.Results: With HRMD-referenced backsets of 25 mm and 50 mm measured at 25°, the head restraint intersected the preferred head locations of 17.9 and 5.2% of the drivers, respectively. An HRMD-referenced backset measured at 22° produced larger accommodation rates than the same backset measured at 25°.Conclusions: The reported distribution of occupant head positions and the resulting restrictions on comfortable head restraint position at various HRMD-referenced backsets and seat back angles help provide guidance for head restraint design. Knowing the actual mean driver-selected seat back angle for a particular vehicle seat and the model presented in this work, a manufacturer can choose a head restraint location that will have a high likelihood of complying with FMVSS backset requirements while also achieving minimal disaccommodation. The findings in this study support the flexibility in the current FMVSS 202a that permits testing at more upright seat back angles than the 25° originally proposed.

Effects of seat parameters and sitters’ anthropometric dimensions on seat profile and optimal compressed seat pan surface

Designing one seat for multi-sitters and multi-activities is challenging especially in a very restrained aircraft economy class cabin. In this paper, the effects of seat parameters and sitters' anthropometric dimensions on seat profile and optimal compressed seat pan surface were studied using a newly built multi-adjustable experimental seat. The ‘optimal’ seat pan contact surface was obtained by controlling the height of 52 cylinders so that the normal contact force was distributed to all cylinders as evenly as possible. With 13 other motorized adjustments controllable by a computer, individual seat profile in the symmetry plane such as seat height, seat pan length, seat pan angle, lumbar protrusion and headrest position were also studied. Data were collected from 36 men and women of varying body size testing 40 seat configurations. Parametric models were obtained for predicting seat profile and optimal compressed seat pan seat surface in function of seat pan and back rest angles for two sitting postures. It is expected that the proposed parametric models provide necessary reference values in seat development for a better fit of a target population of sitters with large varying body size.

Occupant injury risk assessment and protective measures in frontal collision of a bus

ABSTRACTA significant issue worldwide is a bus frontal collision which can result in more than 10 fatalities per incident. The study aims to develop recommendations on injury risk reduction in such frontal collisions. A LS-DYNA and MADYMO coupling method as well as sled tests were employed to investigate the effect of seat layout variables including seat pitch, height difference and back inclination angle on occupant injury to different body parts, protection measures were subsequently developed to minimise occupant injury risk. The results show that secondary collision with the front seat back can cause severe head and neck injuries.Although the lap belt can restrict the movement of the pelvis and lower limbs, the collision and relative slippage between the head and the front seat back still cause a high neck bending moment. The study further reveals that seat layout variables should be design-specified to optimal values that minimise such injuries.

Effect of stacking sequence on properties of coconut leaf sheath/jute/E-glass reinforced phenol formaldehyde hybrid composites

In the present study, the effect of stacking sequence on mechanical, physical, and biodegradability properties of treated coconut leaf sheath/jute/glass fabric reinforced phenol formaldehyde hybrid composites were studied. The hybrid composite laminates were fabricated by using hand lay-up technique. The specimen preparation and testing were conducted as per ASTM standards. Obtained results indicated that the incorporation of coconut leaf sheath with glass fiber of hybrid composites has greater effect on tensile and hardness properties. Coconut leaf sheath fibers treated with NaOH solution shows significant improvement for adhesion between fiber and matrix. Water absorption plots for different periods of immersion indicated that coconut leaf sheath with glass hybrid composites offer better resistance to water absorption than pure natural fiber reinforced composites. Thickness swelling of the hybrid composites increases due to increase in the percentage of water absorption of the composites. From SEM analysis of the tensile fractured surface of hybrid composites, it is found that the failure of composite is due to poor interfacial bonding between fiber and matrix. An overall comparison of all the laminates revealed that the hybrid laminates of coconut leaf sheath with extreme glass fibers plies as skin layer is the optimum combination with a good balance between the properties. So they may be suited in manufacturing of car doors, car interiors, dash boards, headliners, decking, parcel shelves, pallets, spare tyre covers, spare-wheel pan, seat backs, etc.

Evaluation of ozone risk under different air-supply mode in aircraft cabins

PurposeThe purpose of this paper is to evaluate the ozone risk introduced by the mixing air-supply mode, displacement air-supply mode and personalized air-supply mode, respectively, in commercial aircraft cabins.Design/methodology/approachIn this study, a computational fluid dynamics (CFD) model of aircraft cabin has been built to study the distribution of ozone mass fraction and the ozone surface deposition rate on passenger’s face and clothes under the three different air-supply modes, respectively. The distribution of ozone mass fraction has been obtained by calculating the mass concentration of ozone in different location. The ozone surface deposition rate on passenger’s face and clothes has been calculated according to the mechanism of the reactions between ozone and squalene, which is the primary reactant in human sebum.FindingsBy comparing the three air-supply modes, it was considered that the mixing air-supply mode made lower ozone concentration and ozone surface deposition risk in most area, but this was because of the thin air distribution in cabin. The displacement air-supply mode made an uneven distribution of ozone concentration and increased absorbing ozone risk in the breathing zone. The personalized air-supply mode was proper for avoiding ozone harm and making a comfortable air environment. The air supply from the inlet on seat back could not increase the ozone surface deposition risk on passenger’s face.Originality/valueThis paper provides the qualitative and quantitative analysis for ozone risk to the passengers under the different air-supply modes. Findings can provide some suggestions for the designers to optimize the air-supply mode of air distribution system for reducing passengers’ discomfort caused by high-altitude ozone introduction, such as breathing in too much ozone.

Automated recognition of rear seat occupants' head position using Kinect™ 3D point cloud

IntroductionChild occupant safety in motor-vehicle crashes is evaluated using Anthropomorphic Test Devices (ATD) seated in optimal positions. However, child occupants often assume suboptimal positions during real-world driving trips. Head impact to the seat back has been identified as one important injury causation scenario for seat belt restrained, head-injured children (Bohman et al., 2011). There is therefore a need to understand the interaction of children with the Child Restraint System to optimize protection. MethodNaturalistic driving studies (NDS) will improve understanding of out-of-position (OOP) trends. To quantify OOP positions, an NDS was conducted. Families used a study vehicle for two weeks during their everyday driving trips. The positions of rear-seated child occupants, representing 22 families, were evaluated. The study vehicle – instrumented with data acquisition systems, including Microsoft Kinect™ V1 – recorded rear seat occupants in 1120 driving 26 trips. Three novel analytical methods were used to analyze data. To assess skeletal tracking accuracy, analysts recorded occurrences where Kinect™ exhibited invalid head recognition among a randomly-selected subset (81 trips). Errors included incorrect target detection (e.g., vehicle headrest) or environmental interference (e.g., sunlight). When head data was present, Kinect™ was correct 41% of the time; two other algorithms – filtering for extreme motion, and background subtraction/head-based depth detection are described in this paper and preliminary results are presented. Accuracy estimates were not possible because of their experimental nature and the difficulty to use a ground truth for this large database. This NDS tested methods to quantify the frequency and magnitude of head positions for rear-seated child occupants utilizing Kinect™ motion-tracking. ResultsThis study's results informed recent ATD sled tests that replicated observed positions (most common and most extreme), and assessed the validity of child occupant protection on these typical CRS uses. SummaryOptimal protection in vehicles requires an understanding of how child occupants use the rear seat space. This study explored the feasibility of using Kinect™ to log positions of rear seated child occupants. Initial analysis used the Kinect™ system’s skeleton recognition and two novel analytical algorithms to log head location. Practical applicationsThis research will lead to further analysis leveraging Kinect™ raw data – and other NDS data – to quantify the frequency/magnitude of OOP situations, ATD sled tests that replicate observed positions, and advances in the design and testing of child occupant protection technology.

Evaluation of Structural Strength Characteristics According to Cross-sectional Shape of Lightweight Seat Frame

In the present study, FE analysis was performed for characterising structural strength of a seat frame w.r.t. varying sectional shapes as well as different materials of the seat back frame based on the FMVSS 207 regulation in order to obtain the design outline of a lightweight seat frane structure. Four types of materials, i.e., SAPH440, Al7021, Al6082 and carbon/epoxy composites were applied to the seat back frame type beams and their bending behaviours were compared by three point bending FE analysis. Consequently, the lightweight structure of seat back frame with the equivalent strength characteristics of conventional frame was suggested.

A Study on Laser Welding of the Seat Back Frame Applied by High Strength Steels

A Study on Laser Welding of the Seat Back Frame Applied by High Strength Steels

Comparing spatially static and dynamic vibrotactile take-over requests in the driver seat

Vibrotactile stimuli can be effective as warning signals, but their effectiveness as directional take-over requests in automated driving is yet unknown. This study aimed to investigate the correct response rate, reaction times, and eye and head orientation for static versus dynamic directional take-over requests presented via vibrating motors in the driver seat. In a driving simulator, eighteen participants performed three sessions: 1) a session involving no driving (Baseline), 2) driving a highly automated car without additional task (HAD), and 3) driving a highly automated car while performing a mentally demanding task (N-Back). Per session, participants received four directional static (in the left or right part of the seat) and four dynamic (moving from one side towards the opposite left or right of the seat) take-over requests via two 6×4 motor matrices embedded in the seat back and bottom. In the Baseline condition, participants reported whether the cue was left or right, and in the HAD and N-Back conditions participants had to change lanes to the left or to the right according to the directional cue. The correct response rate was operationalized as the accuracy of the self-reported direction (Baseline session) and the accuracy of the lane change direction (HAD & N-Back sessions). The results showed that the correct response rate ranged between 94% for static patterns in the Baseline session and 74% for dynamic patterns in the N-Back session, although these effects were not statistically significant. Steering wheel touch and steering input reaction times were approximately 200ms faster for static patterns than for dynamic ones. Eye tracking results revealed a correspondence between head/eye-gaze direction and lane change direction, and showed that head and eye-gaze movements where initiated faster for static vibrations than for dynamic ones. In conclusion, vibrotactile stimuli presented via the driver seat are effective as warnings, but their effectiveness as directional take-over requests may be limited. The present study may encourage further investigation into how to get drivers safely back into the loop.

Interrater reliability of Algo used by non-occupational therapist members of homecare interdisciplinary teams

Purpose: To determine if non-occupational therapists (non-OTs) with different job titles using Algo, a clinical algorithm for recommending bathroom modifications (e.g., bath seat) for community-dwelling elders in “straightforward” situations, will make clinically equivalent recommendations for standardized clients. Method: Eight non-OTs (three social workers, two physical rehabilitation therapists, two homecare aides and one auxiliary nurse) were trained on Algo and used it with six standardized clients. Bathroom adaptations recommended (one of nine options) by non-OTs were compared to assess interrater agreement using Fleiss adapted kappa. Results: Estimated kappa was 0.43 [0.36; 0.49] qualified as a moderate agreement, according to Landis and Koch’s arbitrary divisions, among the recommendations of non-OTs. However, clinical equivalence is reached, since safety and client needs were met when raters selected two different options (e.g., with or without a seat back). Conclusions: Non-OTs using Algo in the same simulated clinical scenarios recommend clinically equivalent bathroom adaptations, increasing the confidence regarding the interrater reliability of Algo used by non-OT members of homecare interdisciplinary teamsImplications for RehabilitationIn homecare services, non-occupational therapists from different health care disciplines (e.g., homecare aides, social workers, physical rehabilitation therapists) may be asked to select assistive devices for the hygiene care of clients living at home.Algo was designed to guide non-occupational therapists in the selection of assistive devices when performed with clients in straightforward cases.This study indicates that non-occupational therapists using Algo recommend similar and acceptable bathroom adaptations to enhance client safety.

A review of natural fibres, their sustainability and automotive applications

In recent years, the amount of research on natural fibres and natural-fibre-based products has increased substantially. The reason for this increase is due to a greater awareness of the environment and the ever depleting trend of petroleum supplies. Natural fibre composites and in general, natural fibres have a big role to play towards a sustainable environmentally friendly future. The automotive industry is taking big steps toward a more eco-friendly product chain by implementing natural fibres as a base for making various components, such as seat backs, door panels, spare tyre and boot linings. The world production of natural fibres is increasing since the product base is increasing. Each year, more synthetic fibres and high energy consuming products are being replaced by natural-fibre-based products. The reason for this trend is not only due to an increased environmental awareness but also because natural fibres have excellent properties, such as light weight, and they have relatively low costs. This study attempts to review the most commercially important natural fibres and their automotive application and also looks at the properties, chemical composition and cost of some natural fibres being used in industry.

Do users desire symmetrical lumbar supports in task seating?

This research was designed to objectively investigate the desired low back (lumbar) support in a task chair; specifically by allowing a user to self-select the magnitude and location of support. An experimental chair built specifically for this study allowed the users to remotely adjust 35 diodes to achieve their desired level of support. Pressure mapping was used to measure the interface pressure at the user–seat back interface. It was determined that 73.8% of the 201 participants in this study, self-selected asymmetrical lower back support that was at least 20% greater on one side vs. the other. Additionally, 16.9% of the participants self-selected support on one side which was at least twice that of the other side. Contrary to popular practice, participants were found to prefer asymmetric support in the lower back region. It is anticipated that the culmination of this research will aid chair manufacturers in designing adaptable back rests. Practitioner Summary: Most current lumbar supports are designed to move vertically and to symmetrically increase or decrease in firmness as per a user’s adjustment. This investigation highlights that participants tended to select asymmetrical lumbar support, and as such, designers should consider providing lumbar supports that provide the desired support at appropriate locations.

Driver Injury Risk Variability in Finite Element Reconstructions of Crash Injury Research and Engineering Network (CIREN) Frontal Motor Vehicle Crashes

Objective: A 3-phase real-world motor vehicle crash (MVC) reconstruction method was developed to analyze injury variability as a function of precrash occupant position for 2 full-frontal Crash Injury Research and Engineering Network (CIREN) cases.Method: Phase I: A finite element (FE) simplified vehicle model (SVM) was developed and tuned to mimic the frontal crash characteristics of the CIREN case vehicle (Camry or Cobalt) using frontal New Car Assessment Program (NCAP) crash test data. Phase II: The Toyota HUman Model for Safety (THUMS) v4.01 was positioned in 120 precrash configurations per case within the SVM. Five occupant positioning variables were varied using a Latin hypercube design of experiments: seat track position, seat back angle, D-ring height, steering column angle, and steering column telescoping position. An additional baseline simulation was performed that aimed to match the precrash occupant position documented in CIREN for each case. Phase III: FE simulations were then performed using kinematic boundary conditions from each vehicle's event data recorder (EDR). HIC15, combined thoracic index (CTI), femur forces, and strain-based injury metrics in the lung and lumbar vertebrae were evaluated to predict injury.Results: Tuning the SVM to specific vehicle models resulted in close matches between simulated and test injury metric data, allowing the tuned SVM to be used in each case reconstruction with EDR-derived boundary conditions. Simulations with the most rearward seats and reclined seat backs had the greatest HIC15, head injury risk, CTI, and chest injury risk. Calculated injury risks for the head, chest, and femur closely correlated to the CIREN occupant injury patterns. CTI in the Camry case yielded a 54% probability of Abbreviated Injury Scale (AIS) 2+ chest injury in the baseline case simulation and ranged from 34 to 88% (mean = 61%) risk in the least and most dangerous occupant positions. The greater than 50% probability was consistent with the case occupant's AIS 2 hemomediastinum. Stress-based metrics were used to predict injury to the lower leg of the Camry case occupant. The regional-level injury metrics evaluated for the Cobalt case occupant indicated a low risk of injury; however, strain-based injury metrics better predicted pulmonary contusion. Approximately 49% of the Cobalt occupant's left lung was contused, though the baseline simulation predicted 40.5% of the lung to be injured.Conclusions: A method to compute injury metrics and risks as functions of precrash occupant position was developed and applied to 2 CIREN MVC FE reconstructions. The reconstruction process allows for quantification of the sensitivity and uncertainty of the injury risk predictions based on occupant position to further understand important factors that lead to more severe MVC injuries.

Studies on the perception of bass in four concert halls.

The importance of bass to the overall sound quality in concert halls was highlighted at the opening of the Philharmonic Hall in New York in 1962 (Beranek, Johnson, Schultz, & Watters, 1964). The hall provided almost no immediate lateral reflections, and bass could barely be heard on the stalls (Barron, 2009). The parenthetical comments brought up particularly the weakness of the cellos and the double basses. Apart from critique, this observation led to the discovery of the seat-dip effect (Schultz & Watters, 1964; Sessler & West, 1964). The seat-dip effect is the term assigned for the attenuation at low frequencies due to sound propagating almost parallel, that is, at near-grazing angles to the surface formed by the tops of the seat backs. The seat-dip effect is characterized by a main attenuation dip between 80 and 300 Hz, and an attenuation bandwidth that can extend up to 1 kHz.The seat-dip effect is objectively present in all concert halls with seats, but in many halls no noticeable lack of bass is perceived as such. In particular, the shoebox-shaped hall are generally characterized by a rich bass in the stalls (Schultz, 1965). This indicates that the seat-dip attenuation is corrected as the sound energy distribution in the concert hall develops over time. The lack of bass in the direct sound is compensated by reflections that contain the bass and arrive at the listener at nongrazing angles. This phenomenon is referred to as seat-dip recovery or correction.However, it remains unclear when the bass should arrive at the listener's ears. It was hypothesized that the seat-dip effect could be compensated by increasing the reverberation time at low frequencies (Schultz & Watters, 1964; Barron, 1995). However, Bradley and Soulodre (1997) found that the perceived level of bass is not related to the reverberation time at low frequencies. More recent evidence suggest that the bass should arrive with the early reflections (Beranek, 2011; Davies, Cox, & Lam, 1996; Patynen, Tervo, & Lokki, 2013; Soulodre & Bradley, 1995). Furthermore, Kahle (1995) suggested that sound energy arriving between 80 and 160 ms augments the perception of low frequencies. Additionally, Bradley and Soulodre (1997) linked the perceived level of bass to both the early sound level and late sound level. The phase of the reflections may also alter the perceived level of bass (Laitinen, Disch, & Pulkki, 2013; Lokki, Patynen, Tervo, Siltanen, & Savioja, 2011).It is scarcely understood how the seat-dip effect influences the perception of bass. Orchestral instruments that have their tuning range within the seat-dip attenuation range, such as double bass, tuba, and cello, may lack bass and articulation due to the seat-dip effect. For example, Bradley (1991) estimated that the attenuation of the double bass due to the seat-dip effect can be as much as 6 dB. Barron and Marshall (1981) observed that spatial impression is reduced in the presence of lateral reflections that contain the seat-dip attenuation. Davies et al. (1996) obtained a threshold of audibility for the seat-dip attenuation to be 5.7 dB in the 200 Hz octave band of the early energy over 0 to 40 ms. Although the seat-dip effect is generally considered to hamper the perception of bass, recent psychoacoustic research suggests that if the early reflections retain the bass, the lack of bass in the direct sound may actually enhance the overall perception of bass (Walther, Robinson, & Santala, 2013).In addition to the seat-dip effect, the perception of bass in concert halls is affected by other factors, such as the residual absorption by the seats, walls, floor, and ceiling (Beranek, 2004, 2011). In general, hard thick surfaces absorb less bass than thin panels. Second, the vibrations of the stage floor have been proposed to augment the sound of the double bass and the cello connected to the floor via pins. So far, the augmented bass has been shown to be audible at the stage, but not among the audience (Abercrombie & Braasch, 2010; Wulfrank, Lyon-Caen, Jurkiewicz, Brulez, & Kahle, 2013). …

Evaluation of the rattle noise of a vehicle seat using the coherence analysis technique

The complicated transfer path relationship between the vibrations of a seat and the noise at the locations of the driver’s ears was estimated from the residual spectrum. For accurate quantitative estimation of the rattle noise at the locations of the driver’s ears, in particular the partial coherence function of the pure inputs to the output was modelled by considering the correlation between the inputs and the input–output. Whenever a coherence analysis was performed with the noise sources in close proximity selected as the inputs and the noise at the locations of the driver’s ears modelled as the output, the partially coherent output spectrum as a quantitative contribution of the inputs to the output was determined. In this study, we applied a coherence analysis technique to identify the sources of the rattle noise of a seat by visualizing the noise sources with an acoustic camera while excitation of the seat was carried out using a hydraulic exciter. We were able to generate the rattle noise from the headrest stay, the recliner and the front part of the slide while excitation of the seat was obtained using a hydraulic exciter with white noise. We observed that the noise was generated by utilizing a hydraulic six-axis exciter positioned at the driver’s seat of a middle-sized manual transmission vehicle. We determined that the noise measured at the locations of the driver’s ears had a frequency of 58 Hz using acoustic visualization and a coherence technique. It was selected in particular as the target frequency since the 58 Hz resonant frequency caused by the twisting mode of the seat back was identical with the frequency of the rattle noise. Finally, it was verified through a modal test that the rattle noise at 58 Hz was generated by the vibration characteristics of the seat, which depended on gaps between the headrest stay and the guide.

Seat and seatbelt accommodation in fire apparatus: Anthropometric aspects

This study developed anthropometric information on U.S. firefighters to guide fire-apparatus seat and seatbelt designs and future standards development. A stratified sample of 863 male and 88 female firefighters across the U.S. participated in the study. The study results suggested 498 mm in width, 404 mm in depth, and 365–476 mm in height for seat pans; 429–522 mm in width and 542 mm in height for seat back; 871 mm in height for head support; a seat space of 733 mm at shoulder and 678 mm at hip; and a knee/leg clearance of 909 mm in fire truck cab. Also, 1520 mm of lap belt web effective length and 2828 mm of lap-and-shoulder belt web effective length were suggested. These data for fire-truck seats and seatbelts provide a foundation for fire apparatus manufacturers and standards committees to improve firefighter seat designs and seatbelt usage compliance.

渦巻ばねのCAE技術と形状測定技術

Spiral spring has been used in various mechanical applications because of its simple shape. In automotive reclining seat device, when the seat back is tilted backward, spiral spring is tightened elastically. This provides elastic energy that retracts the seat back to its original position. Therefore, it is important to predict spring characteristics such as torque performance. However, in classical theory, it was impossible to predict them with sufficient accuracy. In actual design, it is necessary to make some prototype springs and measure the characteristics for re-design. Furthermore, accurate shape measurement technology is indispensable for quality assurance for volume production. However, classical method has not been sufficient in accuracy and speed. In this report, we provide actual examples of the product quality improvement by the design prediction accuracy improvement with CAE and non-contact measurement technology.

Noncontact Monitoring of Respiration by Dynamic Air-Pressure Sensor.

We have previously reported that a dynamic air-pressure sensor system allows respiratory status to be visually monitored for patients in minimally clothed condition. The dynamic air-pressure sensor measures vital information using changes in air pressure. To utilize this device in the field, we must clarify the influence of clothing conditions on measurement. The present study evaluated use of the dynamic air-pressure sensor system as a respiratory monitor that can reliably detect change in breathing patterns irrespective of clothing. Twelve healthy volunteers reclined on a dental chair positioned horizontally with the sensor pad for measuring air-pressure signals corresponding to respiration placed on the seat back of the dental chair in the central lumbar region. Respiratory measurements were taken under 2 conditions: (a) thinly clothed (subject lying directly on the sensor pad); and (b) thickly clothed (subject lying on the sensor pad covered with a pressure-reducing sheet). Air-pressure signals were recorded and time integration values for air pressure during each expiration were calculated. This information was compared with expiratory tidal volume measured simultaneously by a respirometer connected to the subject via face mask. The dynamic air-pressure sensor was able to receive the signal corresponding to respiration regardless of clothing conditions. A strong correlation was identified between expiratory tidal volume and time integration values for air pressure during each expiration for all subjects under both clothing conditions (0.840-0.988 for the thinly clothed condition and 0.867-0.992 for the thickly clothed condition). These results show that the dynamic air-pressure sensor is useful for monitoring respiratory physiology irrespective of clothing.

Application of Carbon Fiber Reinforced Plastic to Automotive Seat Frames

The purpose of this paper is to develop a lightweight automotive seat back frame structure using CFRP (Carbon Fiber Reinforced Plastic). The shape of CFRP seat back frame was determined so that its manufacturing could be performed in a single process without additional fastening. Three different kinds of analyses were performed to confirm that CFRP seat frame could satisfy FMVSS (Federal Motor Vehicle Safely Standards) requirements. The results of finite element analyses showed that its maximum stresses were 51.1 to 95.5 % of those of steel seat frame structure. Its mass was 56.2% of that of steel seat back frame. CFRP seat frame can provide better fuel economy as well as improved safety.