This research focuses on the dynamic seat comfort in aircrafts specifically during takeoff, landing and cruise through turbulence flight conditions. The experiments are performed using a multi axis shaker table in the Automotive Centre of Excellence (ACE) at the University of Ontario Institute of Technology subjected to sample takeoff, landing and cruise vibration recordings obtained onboard of an actual flight. The input vibrations introduced to the aircraft seats during actual flight conditions and during the experiments in the ACE are compared and it is concluded that the given flight conditions were successfully replicated for the interest of this thesis. The experiments are conducted with two different aircraft seats, economy class and business class. Furthermore, to investigate the importance of seat cushion characteristics in addition to economy and business class seat cushions, three laboratory made cushions were included in the investigation as well. Moreover, the effect of passenger weight is also discussed by conducting the experiments with 1 and 2 identical dummies. It is concluded that static seat properties play a significant role in the comfort perception level as well as flight conditions. Among the three flight condition, landing appeared to be the most uncomfortable case comparing to takeoff and cruise. In addition to experimental work, a numerical study to simulate the flight conditions is undertaken with the initial work of CAD modelling. The simulated responses of the seat is partially matching with experimental results due to unknown parameters of the cushion and the connections of the aircraft seat that cannot be created in the CAD model due to unknown manufacturing processes.

A comprehensive comparison between an air-inflated seat cushion designed for truck seats and a commonly used foam cushion is provided, using a single-axis test rig designed for dynamic seat testing. Different types of tests are conducted in order to evaluate various aspects of each type of cushion; in terms of their response to narrow-band (single frequency) dynamics, broadband input of the type that is commonly used in the trucking industry for testing seats (ISO2), and a step input for assessing the damping characteristics of each cushion. The tests were conducted over a twelve-hour period -- in four-hour intervals -- measuring the changes that occur at the seat cushion over time and assessing how these changes can affect the metrics that are used for evaluating the cushions. The tests indicated a greater stiffening of the foam cushion over time, as compared with the air-inflated cushion that showed almost no change in stiffness when exposed to a static weight for twelve hours. Furthermore, pressure measurements at the seat showed higher-pressure concentrations for the foam cushion at the bony prominence of the seat profile -- namely, the ischial tuberosities -- as compared to the air-inflated cushion. A series of tests aimed at evaluating the damping properties of each cushion showed both cushions to have nearly identical damping properties. Other methods used for evaluating the dynamic properties of the two seat cushions included those recommended by studies in the past, as well as new techniques that were developed specifically for this study. The new techniques, named Seat Pressure Distribution (SPD%) and Area Pcrms (aPcrms) for the purpose of this study, are formulated such that they can best highlight the dynamic differences between different types of seat cushions, and their effect on driver comfort. The results show that the air-inflated seat cushion can provide significant improvements in pressure distribution between the seat cushion and the driver, therefore providing a more comfortable ride and causing less fatigue. / Master of Science

The visual domain design constitutes the general designers communication basis for communicating messages of product attributes. In the design of an automobile seat where mainly the accommodating functions remain constant, an automobile seat&rsquo / s &ldquo / style&rdquo / affords the ability to provide certain meanings with affective connotations. Treating style aesthetics as a source of information, the communication of &ldquo / comfort&rdquo / can be provided via forms and other attributes. The literature provides strong evidence that comfort is related with aesthetics of any object in use, especially creating expectations towards the product. The &ldquo / Aesthetics of comfort&rdquo / can be explained as a variable intensity &ldquo / feeling&rdquo / or &ldquo / attitude&rdquo / regarding an entity of factors or characteristics of a multidimensional construct. Implemented by different layouts and cues, the consumer should be assisted in understanding the qualities of an automobile seat, such as comfort. As a result of the field study conducted, significant difference was found to exist in between the perception of visual comfort three production seat designs. A positive attitude about comfort towards an automobile seat was found to be influential in positively effecting the perception of seated comfort.

In recent years increased emphasis has been placed on improving seat comfort in automobiles. This is partly due to research showing that prolonged driving is associated with increased risk of musculoskeletal disorders, but largely because driver comfort is now viewed as an increasingly important aspect of the competitive marketing of vehicles. Driving is firmly cemented as a major part of most people s daily life across the world and people are now spending more time in their vehicles than ever before. As urban congestion continues to rise, commuting distances and durations will progressively increase, subjecting drivers to the risks of long duration driving more often. Consequently the automotive industry has invested in designing seats that perform better under increased usage durations and ergonomics has played a vital role in the design of new seats. However, the ability to design a successful seat relies heavily on the capacity to accurately evaluate the comfort of a vehicle seat and one major issue that has been highlighted with the current state of automotive ergonomics research is the standardisation of comfort evaluation techniques. This research aimed to tackle these issues by investigating the effects of long duration driving on discomfort and the range factors associated with driver discomfort. Furthermore, the ultimate goal of this research was develop and evaluate a novel objective measure of driver discomfort that focused on driver seat fidgets and movements (SFMs) with the aim of standardising discomfort evaluation within the automotive industry. Three laboratory studies and one field observation were conducted to address these aims whereby subjective and objective evaluations of discomfort were conducted during long term driving (ranging from 60 - 140 minutes). The results determined that a measure of driver SFMs can be effectively implemented into long duration driving trials to evaluate the effects of long term driving and vibration exposure on driver discomfort and subsequently used to make accurate predictions of overall discomfort. Large positive correlations have been determined between measures of SFMs and subjective ratings of overall discomfort (r2 > 0.9, P < 0.05) and the SFM method has been successfully repeated under a range of driving conditions. Driver seat fidget and movement (SFM) frequency is shown to significantly increase congruently with subjective ratings over the duration of a long term drive as drivers seek to cope with increased discomfort. It is proposed that drivers will record movements in the vehicle seat when discomfort reaches a threshold that is consciously or unconsciously perceived and as the duration of driving accrues, drivers will reach this threshold with increased frequency. A measure of both SFM frequency and total accumulative SFMs have been shown to accurately predict discomfort ratings and provides the basis for discomfort evaluations to be made via remote monitoring, removing the need for subjective assessment. During a long term drive, there becomes a point upon which improvements in seat design become ineffective as extended duration driving will result in discomfort regardless of how well the seat has been designed. It was shown that drivers will move in the vehicle seat to cope with increased discomfort and in addition, another method of combatting the negative effects of long term driving was investigated. Subjective and objective evaluation determined that breaks from driving will reduce discomfort both immediately and upon completion of a long term drive. Furthermore, these benefits were increased when drivers left the vehicle seat as discomfort was reset when drivers took a 10 minute walk. Walking during a break from driving can be considered the ultimate SFM. Drivers are recommended to plan breaks from driving when conducting a long duration journey in order to minimise discomfort and when taking a break, drivers should take a walk rather than remain seated in the vehicle.

During the last couple of years several studies have been conducted to investigate how children move and position during car rides. This in order to map when, and for how long children sit in positions that are not safe as well as to identify the reason for these movements. One of the conclusions is that children do not always sit comfortable in today’s belt-positioning boosters and thereby they chose positions that are unwanted for safety reasons. The aim for the master thesis has thereby been to improve seating comfort for children while traveling safely in the rear seat of a car. The target group has been children in ages 5-11 years old with body height 110-145 cm, a Swedish population 50 percentile has been used for the extreme dimensions. The master thesis process is divided in three phases; Discovery, Development and Testing and Evaluation. In the Discovery phase information in the areas child safety, child methodology and comfort was gathered through literature study, interviews with experts, benchmarking and a focus group with parents. As a final step customer needs were formulated. In the Development phase a workshop with children was initially performed to complement the customer needs with inputs from the users. The customer needs were afterwards reformulated into a specification of requirements and five comfort hypotheses. Finally a prototype was developed, designed from the requirements with the purpose to validate the comfort hypotheses, using an anthropometric design method (Osvalder, et al., 2010). In the final phase, Testing and Evaluation, the prototype and reference belt-positioning boosters were evaluated by children in two user studies; one static study and one on road study, to evaluate comfort features and try out different seating comfort evaluation methods. The result is divided into child seating comfort characteristics and child seating comfort methodology guidelines. To assist future development of belt-positioning boosters, seven comfort features are defined to help children ride comfortable in a safe position in the car. Furthermore, 13 child methodology guidelines are formulated to help further seating comfort evaluation with children. Conclusively to make children sit comfortable and safe positioned in the car they should be seated in a belt-positioning booster with headrest, backrest, seat cushion and foot support, the supporting parts need to be perceived as soft around head, back and under the buttock and all parts need to be dimensioned for all children in the target group. The size of the belt-positioning booster and the combination of foam thickness, foam hardness and shape are the main factors for affecting the perceived seating comfort. Furthermore, children shall be included as both design partners and testers during the development of belt-positioning boosters. During the prototype development static comfort evaluation with children should be done repeatedly to verify measurements, shape and foam hardness. To evaluate comfort both static evaluation and on road evaluation should be performed since comfort varies over time. Data should be collected subjectively from children through quantitative methods, such as rating scales, and qualitative methods, such as general questions regarding comfort/discomfort experience. Video observations can identify children’s position during car rides. Different positions can be timed and together with subjective data reasons for repositioning can be identified.