Seat Design Research Articles

Integrating Kansei engineering, analytic hierarchy process, and quality function development in elderly-oriented seating design

To deeply understand the psychological and emotional needs of the elderly population, this study proposes a seat design method combining Kansei engineering (KE), analytic hierarchy process (AHP), and quality function development (QFD). The method aims to fulfill the functional needs of the seat and focuses on capturing the emotional imagery of the elderly group, thus enhancing the emotional experience of the users. Factor analysis (FA) was used to conceptualize the user’s perceptual vocabulary data, AHP to assess the relative importance of these perceptual words, and morphological analysis to deconstruct the characteristics of the seat components. Finally, the mapping relationship between user perceptual data and design features was established through QFD. The FA and AHP results showed that the emotional needs of the elderly for seating are primarily focused on the sense of lightness (32.5%), simplicity (45.7%), and sophistication (21.8%); and QFD analysis results show that among seating components, the No. 6 seat back, No. 1 seat cushion, No. 2 door post, and No. 2 seat leg have the highest importance and can best meet the emotional needs of elderly users. This design method effectively improves the product’s suitability for the elderly and provides a valuable reference for related product design.

Effects of rear seat design on occupant injury risk during frontal crashes: A parametric study using finite element analysis

Rear seat occupants in newer vehicles might face a higher injury risk during traffic collisions compared to front seat occupants, whose seats have significantly improved over the last few decades. In addition, the rise in ridesharing and automation could increase exposure of rear seat occupants. Therefore, this study aims to evaluate the effects of various characteristics of rear seat design on occupant safety during frontal collisions. A simplified seat model was developed and validated against sled test data (ΔV of 32 km/h). Ten seat characteristics of the simplified seat were then investigated using two Design of Experiments techniques. Occupant injury risks were derived from crash simulations, and the correlation between the seat design and injury probabilities was evaluated. The results indicated that a more vertical seat back angle, specific D-ring location (a more rearward, inboard, a higher), and seatbelt anchorage location (wider and higher) would improve rear seat safety performance. Optimal seat models were developed based on the DOE results, and their superior performance was confirmed in finite element (FE) crash simulations. Overall, the whole-body injuries in optimized seats were significantly lower than the average injury risk in the DOE cases for both 50th percentile male Hybrid III (38.5% vs. 70.5%) and THOR (52.8% vs. 78.1%) dummies. These findings suggest substantial potential for improving rear seat designs to enhance occupant safety.

Design Improvement, Thermal Efficiency Optimization and Comparative Study of a Natural Draft Chulha

ABSTRACT This work inscribes the rural-based biomass cookstove (chulha) fabrication with the aim of modification and enhancement of the existing natural draft low smoke heat-efficient stoves and also comparing its thermal efficiency output. This study is important from the perspective of a rural society who cooks their daily meals on biomass-based cookstoves/chulhas. Enhancing its thermal efficiency and reducing smoke emissions from biomass combustion in the cookstove are the primary focuses of this work. Principle used to design the improved chulha is double co-axial cylinder secondary combustion. Mild steel is used for fabricating maximum parts of the stove including the outer cylinder surface, and the inner cylinder surface is made of galvanized steel, and the insulation between both the surfaces of the cylinders is made of fiber glass wool. Addition of a novel insulating material in the chulha for thermal insulation, resizable air inlet, design and incorporation of smoke rings and pot seat in such a way that no smoke passes through the cooking utensil assisted in achieving better thermal efficiency of the cookstove. Pine wood, bamboo, sagun wood, sal wood and neem wood have been selected as per local availability as biomass feedstock for combustion. To calculate the thermal efficiency, a water boiling test (WBT) has been performed. Best thermal efficiency of 47.08% has been achieved for pine wood biomass feedstock and due to proper placements of the grate and the air inlets in the improved chulha design. Also, a very negligible or no smoke has been observed due to the introduction of the advanced design of the smoke ring and pot seat and the chimney for the outlet making a green energy-efficient biomass cookstove.

Toward the Design of an Ultra-Light Car Seat With a Reclining Back Rest

To reduce the weight of a seat of a city car (A-segment), a car seat was developed. First, a questionnaire was used to define the main functions the occupants prefer to have in the seat. The reclining and forward afterwards movement of the seat were seen as most important. Therefore, a reclining mechanism was built into the lightweight chair. This seat was tested by 39 participants and compared with a benchmark seat of the Toyota Aygo. It was clear that comfort testing is difficult comparing a full developed car seat with a prototype, which still needs development. Nevertheless, the comfort was comparable between the two seats and the shoulder space of the new seat was appreciated. The conclusion is that it is possible to develop a lighter weight car seat, which has the main features preferred by occupants, but further development is needed.

Multi-objective optimization of automotive seat frames using machine learning

The optimal design of automobile seats plays an important role in passenger safety in high-speed accidents. In order to enhance the accuracy of the prediction of the input variables and output response of the seat, a hybrid machine learning prediction model that combines the improved gray wolf optimizer (IGWO) and back propagation neural network (BPNN) has been proposed, and the prediction effect of the model was validated using the seat simulation data. Initially, based on the experimental data, finite element models were developed for eight typical working conditions of automobile seats and their accuracy was validated. Subsequently, the energy absorption to mass ratio method was employed to screen the design variables, resulting in the selection of 17 thickness variables and 15 material variables. Thereafter, the gray wolf optimizer (GWO) algorithm underwent enhancement through the incorporation of the dynamic leadership hierarchy (DLH) mechanism and the revision of the positional formula, yielding the IGWO algorithm. Following this, the IGWO algorithm was applied to optimize the hyperparameters of BPNN, culminating in the establishment of the IGWO-BPNN model. Ultimately, the seat multi-objective optimization design process was addressed using multi-objective gray wolf optimizer (MOGWO) to achieve the Pareto frontier, while the decision-making was conducted using the combined compromise solution (CoCoSo) method to determine the best trade-off solution. Furthermore, the effectiveness of the proposed optimal design method is evidenced by comparing the baseline design, simulation analysis, and optimal design methods. The results indicate that the optimized automotive seat frame achieves a reduction in cost by 20.7 % and mass by 22.9 %, simultaneously maintaining safety performance. Consequently, the proposed optimization design methodology is demonstrated to be highly effective for the multi-objective optimization design of automotive seat frames.

Integrated Design Methods for Sustainable Public Seating in Urban Communities—A Shanghai Case Study

In the context of sustainable regeneration of urban communities, the sustainable construction of community urban furniture has gradually been emphasized. This study focuses on the existing problems of experience, culture, environmental protection, function, and other aspects of community urban furniture; starts from the user’s perspective to screen the user’s sustainable design needs for community public seating; and combines the scientific method to quantify and transform them into design factors to form a reasonable community sustainable public seating design program. Taking the public seating in Gumei Community Park in Shanghai as an example, the study adopts the qualitative research method to obtain demand indicators of users. It utilizes the integrated design framework of “AHP-QFD-FBS” to quantify the user needs and maps them into the product structure to identify the ten factors affecting the sustainability of public seating. A community co-creation workshop was conducted to complete a sustainability assessment with the help of life cycle assessment and scales. From the perspective of residents’ needs, it emphasizes the scientific process of demand transformation and ultimately produces sustainable design factors and serialized products for public seating. This approach introduces new ideas for the sustainable renewal of urban furniture and enhances the quality of urban residents’ leisure time.

Design and analysis of folding mechanism for automotive seats based on space maximization

To solve the problem of maximizing space utilization of car folding seats within limited spatial constraints, a design method for space-maximizing four-bar folding seat hinges is proposed. First, we will investigate the existing types of car folding seats, identify the mainstream configurations, and determine the optimal position of the four-bar linkage hinge point based on the constraints present within the car using theoretical analysis methods. Secondly, kinematic and dynamic models of the four-bar linkage mechanism are established, followed by the formulation of kinematic and dynamic equations. Finally, numerical methods are employed to solve these equations and obtain the kinematic and dynamic characteristics. The results indicate that the design method proposed in the article, which aims to maximize the space of the hinge four-bar folding seat, is efficient and feasible. This approach optimizes the utilization of interior space and enhances passenger comfort while accommodating the folding function of the seat within the existing vehicle environment. This method holds significant engineering implications for the design of folding seats in similar types of vehicles.

Multi-objective ergonomics design model optimization for micro electric cars via response surface methodology

Despite advancements in ergonomic comfort assessments in automotive design, optimizing seat dimensions within the constrained spaces of micro-electric cars presents a substantial challenge. In this study, response surface methodology (RSM) is utilized for the ergonomics design of a micro electric car in the conceptual design phase. Specifically, five critical seat dimensions are analyzed: Seatback Angle, Seat Base Angle, Steering Wheel Height from Car Base, Distance from Seat Base to Pedals, and Distance from Seat Base to Steering Wheel. The analysis took place using a 2-level full factorial design L32 orthogonal array. The optimal dimensions are determined using RSM, such as the mean comfort level and signal-to-noise ratio are maximized, and the standard deviation for multiple drivers is minimized. Three regression models are formulated for the three responses, and their adequacy is checked using different methods. The optimal dimensions are obtained and verified through digital human modeling simulation. This research offers practical guidelines for the ergonomic seating design in micro-electric vehicles, enhancing comfort without compromising space efficiency.

Antagonistic Feedback Control of Muscle Length Changes for Efficient Involuntary Posture Stabilization.

Simultaneous and cooperative muscle activation results in involuntary posture stabilization in vertebrates. However, the mechanism through which more muscles than joints contribute to this stabilization remains unclear. We developed a computational human body model with 949 muscle action lines and 22 joints and examined muscle activation patterns for stabilizing right upper or lower extremity motions at a neutral body posture (NBP) under gravity using actor-critic reinforcement learning (ACRL). Two feedback control models (FCM), muscle length change (FCM-ML) and joint angle differences, were applied to ACRL with a normalized Gaussian network (ACRL-NGN) or deep deterministic policy gradient. Our findings indicate that among the six control methods, ACRL-NGN with FCM-ML, utilizing solely antagonistic feedback control of muscle length change without relying on synergy pattern control or categorizing muscles as flexors, extensors, agonists, or synergists, achieved the most efficient involuntary NBP stabilization. This finding suggests that vertebrate muscles are fundamentally controlled without categorization of muscles for targeted joint motion and are involuntarily controlled to achieve the NBP, which is the most comfortable posture under gravity. Thus, ACRL-NGN with FCM-ML is suitable for controlling humanoid muscles and enables the development of a comfortable seat design.

A dimensional design of tractor seat based on Iranian anthropometric characteristics.

The dimensional seat design process should consider both the users' tasks and their physical characteristics. To use an approach for the design and evaluation of seat dimensions based on the anthropometric characteristics of the Iranian population and the requirements of tractor operators. Some existing equations relating the seat dimensions to anthropometric characteristics were modified according to logical justifications and international standards. A new mathematical-statistical method was used to extract the equations estimating the constant seat dimensions based on the theoretical maximizing of the accommodation level. In addition, an Overall Seat Accommodation Score (OSAS) was developed to represent the mean of seat dimensions accommodation level and dimensional accommodation equality, simultaneously. The dimensional seat design can be affected under different conditions of adjustability, esthetic, and space limitations. However, it was shown that it is possible to improve the design of tractor seats without any significant increase in the final cost and complexity. A new approach was used for tractor seats for a sample of Iranian operators and can be used for the design and evaluation of tractor seats for other target populations.

When design meets material to transform public transport into a status symbol. Experimental study on bus seat design

When design meets material to transform public transport into a status symbol. Experimental study on bus seat design

Semiactive Car-Seat System for Rear-End Collisions

This study proposes and simulates a smart system that can be used in production car seats to decrease whiplash risk in rear-end crashes. A sliding seat incorporating a semiactively controlled magnetorheological (MR) damper model positioned under the seat-pan is simulated with a validated biofidelic human body model. Since this is the first study that demonstrates a computer controlled anti-whiplash car seat system to the best of the authors’ knowledge, a benchmark analysis is carried out to compare the proposed semiactive seat with a state-of-the-art passive anti-whiplash car seat using 23 different crash pulses, including the moderate and high severity crash pulses within the European New Car Assessment Program (EuroNCAP) whiplash risk assessment framework. The proposed semiactive design outperforms the passive seat design by further reducing the values of the critical EuroNCAP whiplash criteria, such as NIC and Nkm, together with the loads acting on the upper neck. The semiactive seat lowers the upper-neck shear force by an amount of 4 kg and 7 kg while lessening the NIC by 10% and 21% and Nkm by 9% and 56% for the EuroNCAP crash pulses, having a delta-V of 16 km/h and 24 km/h, respectively. The findings presented in this paper can aid in the design of car seats to further mitigate whiplash risk in rear-end crashes.

Head injury mechanisms of the occupant under high-speed train rear-end collision

To improve the passive safety of high-speed trains, it is very important to understand the mechanism of head injury in high-speed train collisions. In this study, the head injury mechanisms of occupants in high-speed train rear-end collisions were investigated based on the occupant-seat coupling model, which included a dummy representing the Chinese 50th percentile adult male. The typical injury responses in terms of skull fractures, brain contusions, and diffuse axonal injury (DAI) were analyzed. Meanwhile, the influences of collision speed and seat parameters on head injury response were examined. The simulation results indicate that the skull fractures primarily occur at the skull base region due to excessive neck extension, while the brain contusions and DAI result from the relative displacement of different brain regions. The increase in collision speed will promote the probability of skull fracture, brain contusion, and DAI. Seat design modifications, such as reduced seat spacing, increased seat backrest angles, and selecting the appropriate cushion angle (76°) and friction coefficient (0.15), can effectively mitigate probably occupant's head injury.

Ergonomic Design of Noseless Bicycle Saddle using UPVC/Silica-Aerogel

Introduction: During cycling most of the people suffer from perineal pain due to the pressure acting on the perineal area by the nose of the seat. Also Unsupported sitting on the saddle in a forward bending posture for longer time induce low back pain (LBP) among cyclists. So this paper presents the design of noseless bicycle seat with backrest using UPVC/Silica-Aerogel. Methods: This seat is designed as per the anthropometric dimensions of human body. Various parameters such as Lumbar position, seat tilt angle, seat position, backrest angle, seat height, backrest height, seat and backrest width are considered and the optimal value is determined while designing. The material chosen for the base of seat is UPVC/Silica- Aerogel composite and the cushioning material is chosen as polyurethene foam. The design is executed in 3D modelling software and validated using FEA package. Results: The maximum stresses induced in the newly proposed material UPVC/Silica-Aerogel (4.41MPa) is lesser than its yield strength (59 MPa). The maximum anterior stress of noseless seat is found out to be 24.5 kPa which is lower than that of the saddle with nose (41 kPa). Conclusion: As the anterior stress of noseless seat is lesser, the perineal pressure of cyclists is greatly reduced and this decreases the health problems associated with the perineal pressure. Also the backrest of the seatpan enhances the supporting of back muscles and reduces LBP among cyclists.

Design and Simulation of Seats for Emergency Landing Conditions in Electrical VTOLs

Emerging electrification technologies in aviation and recent advances drive the increased usage of electrical vertical take-off and landing (VTOL) air vehicles. Weight considerations are predominant due to the weaker powertrain and lower payload capacity. Moreover, most systems are automated, and there is no distinction between pilot and passenger seats anymore. Conventional aircraft seating typically exhibits excessive weight, necessitating the development of lightweight troop seats with simple designs and textile seat pans and backrests. This research focuses primarily on the design aspects of these lightweight troop seats. There are already guiding military standards and civilian codes for physical tests for passenger or pilot seats. Nevertheless, there needs to be a comprehensive document combining all of these and explaining how simulation tools can be practically used for the same purpose. Consequently, a generic design was generated based on the troop seat of military helicopters, which was then tested and simulated virtually by finite element analysis according to MIL-S-85510, CS27, and CS29 standards. After finalizing the static tests for forward, rearward, lateral, downward, and upward g forces on a 10-degree floor deformation in the longitudinal axis, implicit dynamic tests were conducted with loading in longitudinal and vertical directions as specified by the MIL-S-85510 standards. Then, hotspot analysis is made for stress interpretation. As a result, a near-optimum design was achieved with stresses 10% lower than the yield stress of the materials, which can be used on board an electrical VTOL.

Solutions of Navier Stokes equation and application on aerodynamics

The Navier-Stocks equation (NSE) was derived based on Newtons second law and Eulers equation with the viscosity effect. The continuity of mass, conservation of momentum and energy contribute to the motion of fluid. This paper discusses the hypothesis and theories of the solution of the 3D NSE corresponding to the boundary and initial conditions from previous research. Meanwhile, this paper focuses on the study of solutions and turbulence models of NSE contributed to the applications of aerodynamics. Machine Learning and Neural Networks are applied to the solution of the NSE to improve the accuracy of prediction of fluid motion. Aerodynamics applications on airfoil, turbulence model, design of propeller and ejection seats are discussed with analysis of solutions of Navier-Stocks equation. With the contribution of Machine learning, accurate and global solutions are expected to be computed for the NSE in the future.

A thermal comfort assessment on semi-outdoor sports stadiums located in 3 different climate zones in China

The thermal environment of sports stadiums, one of the biggest public facilities in the city, can easily impact the health of tens of thousands of people. Semi-outdoor stadiums are susceptible to summer heat waves due to global warming. Overall, this paper provides insights into the thermal comfort conditions in semi-outdoor sports stadiums in three different climate zones in China. Through field research, a method is provided to monitor the thermal environment in the stands of a big stadium using eight sensors. Stadium occupants' thermal comfort is assessed using the Universal Thermal Climate Index (UTCI), and the effects of various climatic conditions are examined. The results of the study show that the north side of the stadium stands is the point with the highest thermal risk, even if the climatic zones are different. The distribution of thermal comfort in the stands will be directly impacted by the stadium's roof prototype. The UTCI has modest sensitivity to wind speed and great sensitivity to the three climatic parameters of air temperature, mean radiant temperature, and relative humidity. This implies that in the stadium grandstand, the shading strategies will enhance the thermal environment more effectively than the natural ventilation strategies. The findings suggest that a combination of passive and active strategies can be used to improve thermal comfort, such as asymmetrical seating design, full wrap-around roofs, and scheduling events to avoid peak heat stress.

Reducing musculoskeletal disorders in iron ore mine operators: A fuzzy-based intervention approach.

This study focuses on evaluating the exposure to whole-body vibration (WBV) and association of musculoskeletal disorders (MSDs) with various risk factors among dumper operators in the mining industry. Despite the issue's significance, prior research has been limited. The study introduces a novel fuzzy-based approach for identifying, selecting, and prioritizing safety measures to mitigate MSD risks. Data collection comprised face-to-face interviews, anthropometric measurements, Rapid Upper Limb Assessment (RULA) scoring for posture assessment, and the Nordic Musculoskeletal questionnaire for assessment of MSD prevalence. Multiple linear and logistic regression models were used to analyse the contributing risk factors to MSDs and WBV exposure. These risk factors formed the basis for a practical approach to select appropriate safety measures based on fuzzy based aggregation method of expert's judgment aimed at mitigating the risk of MSDs. The results revealed that the risk factors such as poor work posture, WBV exposure and poor seat design were significantly associated with neck (adjusted odds ratio aOR = 4.81), upper limb and shoulder (aOR = 3.28), upper back (aOR = 5.09), and lower back pain (aOR = 3.67) at p < 0.05. Using these factors to formulate safety measures to reduce MSD risk, the minimization of sharp turns and abrupt changes in elevation in designing the haul roads, scheduled maintenance practices, and ergonomic seat design were found as important safety measures in this study. Our unique methodological approach in occupational health research could be highly beneficial for tailoring safety measures at the unit level with minimal effort.

A study on the optimal design of UAM seats

The objective of this study is to enhance the efficiency of urban air mobility (UAM) air transportation by determining the optimal design, materials, and processes of seven different manufactured fiber-reinforced plastics (FRP), and to confirm their applicability for next-generation UAM aircraft seats. Structural designs for the aircraft seat models were carried out using carbon fiber-reinforced plastic (CFRP), glass fiber-reinforced plastic (GFRP), and GFRP chop materials, employing Autoclave, Hot-press, and vacuum-assisted resin transfer molding (VaRTM) processes, resulting in a total of seven FRP configurations. It was confirmed that CFRP seats were 50% lower weight than aluminum models, while GFRP seats showed a 30% reduction. Although Autoclave processing resulted in the highest tensile strength at 985[Formula: see text]MPa, VaRTM processing also produced strength levels comparable to Autoclave processing. Structural integrity assessments of the seat models, utilizing the Korean aviation standards (KAS), confirmed that the designed seat models exhibited no failure or deformation under the conditions required by the technical standards. This study provides insights into the potential application of the seven types of FRP materials in the design of aircraft seats, offering weight reduction benefits and meeting the structural integrity requirements outlined by KAS.

Design of a metal additive manufactured aircraft seat leg using topology optimization and part decomposition

PurposeThe lightweight design of aircraft seats can significantly improve fuel efficiency and reduce greenhouse gas emissions. Metal additive manufacturing (MAM) can produce lightweight topology-optimized designs with improved performance, but limited build volume restricts the printing of large components. The purpose of this paper is to design a lightweight aircraft seat leg structure using topology optimization (TO) and MAM with build volume restrictions, while satisfying structural airworthiness certification requirements.Design/methodology/approachTO was used to determine a lightweight conceptual design for the seat leg structure. The conceptual design was decomposed to meet the machine build volume, a detailed CAD assembly was designed and print orientation was selected for each component. Static and dynamic verification was performed, the design was updated to meet the structural requirements and a prototype was manufactured.FindingsThe final topology-optimized seat leg structure was decomposed into three parts, yielding a 57% reduction in the number of parts compared to a reference design. In addition, the design achieved an 8.5% mass reduction while satisfying structural requirements for airworthiness certification.Originality/valueTo the best of the authors’ knowledge, this study is the first paper to design an aircraft seat leg structure manufactured with MAM using a rigorous TO approach. The resultant design reduces mass and part count compared to a reference design and is verified with respect to real-world aircraft certification requirements.