Seat Components Research Articles

Effect of HVOF spray coating on the tribological surface of onshore gate valves

Gate valve is one of the most common design concepts in onshore Oil & Gas installations. This equipment is composed of a wedge-shaped obturator that performs linear sliding movements during activation. Fluid sealing is achieved through metallic contact between the surfaces of the gate and seat components. Metal surfaces are commonly hardened by heat treatment or coated with Stellite 6 alloy by plasma-transferred arc welding (PTAW). The application of high-velocity oxygen fuel (HVOF) coatings on these surfaces for wedge-gate valves has not yet been foreseen. In addition, comparative studies on the tribological performance of technical surfaces used in onshore wedge-gate valves are also scarce. Therefore, this study presents the results of tests performed on specimens using a ball-on-flat tribometer with linear reciprocating sliding, simulating a gate valve tribosystem in operation: flat (gate) and ball (seat). Martensitic stainless steel 13Cr was used with the contact interfaces under the following conditions: (A) heat treated, (B) Stellite 6 coating by PTAW, (C) Stellite 6 coating by HVOF, and (D) tungsten carbide coating by HVOF. The flat/ball tribological pairs investigated were A/B (TRIM 8), B/B (TRIM 5), C/B, and D/B. The coefficient of friction (COF), surface wear, and wear mechanisms were comparatively evaluated. The results showed that the newly proposed surfaces (C and D) are promising alternatives to reduce material consumption and improve the performance of valves in operation according to the application requirements.

Vibrational comfort improvement for a passenger car driver seat

Abstract This paper presents an experimental study aimed at providing new insights into passenger vehicle driver seat vibration. The study investigates the effects of various driver seat components on the damping coefficient. By employing a design for six sigma method, an optimized seating solution is proposed to enhance seat comfort levels. The control factors used in this study include seat cushion upholstery, topper foam, cushion foam, pulmaflex, torsion bar and seat structure. Seat position, foam thickness and body mass are considered as potential noise factors. Subjective evaluation of seat comfort is conducted using the SAE J 1441-2016, comparing three different passenger car driver seats. The seats are disassembled from the vehicles and mounted on a six-degree-of-freedom shaker test bench. Vertical vibration data are filtered, and transmissibility curves are experimentally obtained from the seat rail to the seat cushion via a pad. Uncomfortable seat prototypes are then manufactured, and alternative configurations are tested on the shaker. The objective and subjective evaluations of the seat prototypes reveal that lower foam hardness, higher foam density, and flexible upholstery contribute to improved comfort levels. Moreover, the prototype seat with optimum parameters receives a subjective evaluation SAE score of +0.75, indicating an enhancement in comfort.

Prediction of sound absorption properties of audience chairs for music performing spaces using computer simulations

This study investigated predicting method of random incidence sound absorption coefficient of the audience chairs by computer simulation with the normal incidence sound absorption properties of seat components using an impedance tube. The real audience chairs were measured in a reverberation room to verify the established computer simulation model. Using fitted computer simulation model, sound absorption characteristics of chairs were discussed in terms of chair design parameters such as spacing between rows, height of backrest of chairs and sound absorption of back and seat cushions. As results, contribution of each seat components on sound absorption of the whole audience chairs was examined. Back and seat cushions were the most dominant factors to design audience chair absorption. In addition, sound absorption shows a decreasing tendency in all frequencies by increasing spacing between rows. It also shows an increasing tendency in range of 250 to 500 Hz by increasing height of the backrest of chairs.

Durability Analysis in Seat Components based on Design Criteria

In this study, the suitability of the M1 class vehicle rear seat according to the ECE R17 luggage retention regulation has been examined. Strength and cost improvement studies were carried out on the seat corner component. The development studies for the seat to be tested according to the boundary and loading conditions specified by the ECE R17 regulation were created in the finite element method pre-processing software Hyper Mesh and the analysis was carried out in the RADIOSS solver. The design of the seat, which was determined by finite element analysis results, was verified by physical tests.

High Performance Valve Seat Materials for CNG Powered Combustion Engines.

The conventional copper infiltrated high speed steel (HSS) valve seats used in gasoline engines are not suitable for CNG combustion because the exhaust gas temperature is at least 80 °C higher, which drastically shortens the service life of the engine valves. Therefore, a proprietary high-alloy HSS-base material was designed to combat hot corrosion and mechanical wear of valve seat faces in CNG fuelled engines. A batch of −100 mesh water atomized HSS powder was commissioned. The powder was vacuum annealed in order to reduce oxygen content and increase its compressibility. To improve the final part machinability, 1.2% MnS was admixed to the HSS powder prior to compaction. The green compacts were sintered at 1135 °C in nitrogen to around 83% TD and subsequently infiltrated with a copper alloy. After installing the valve seat components on a cylinder head, the engine was tested for 100 h according to the automotive industry valve seat wear test procedures. Both the periodic 8-h checks as well as the final examination of the valve seats showed very slow wear, indicating their suitability for CNG powered engines.

Implementasi SMED: Perbaikan Waktu Changeover Part pada Line Produksi Seat di PT. Selamat Sempurna, Tbk

PT. Selamat Sempurna, Tbk is a company that manufactures automotive parts, namely car filters. This filter product has many part numbers. In this company has one of the production lines, namely Line Seat Press Shop, this line produces components from filters, namely seat components. Seat is the main part of the filter component that functions as a filter holder to the engine. This Seat component consists of several part numbers (shapes or variations) following the filter product, and some part numbers handled by the manual engine B070 & L224 will affect the changes in the production engine settings. This production machine includes machines that require time in a slow setup process for switching dies when switching from one part number to another part number compared to other machines, because the element of the process setting is long. With a fishbone diagram, the root cause of the Change Over Part long problem on the machine is from the method category (there is no preparation desk dies and there is not separation of external setup and internal setup). Previously the time needed for Change Over Part was 1961 seconds. After knowing the root cause of the problem and the improvement of the time needed is only 866 seconds. The time difference is 1067 seconds, so save on average time 1095 seconds or 18 minutes / setup. Keywords: Filter product, Change Over part (COP), Fishbone Diagram, Setup, Process Elements.

Design of automobile car seat vibration analysis due to road excitation using CATIA

Four wheelers are still the most convenient personal road transport preferred by family since its invention for a comfort drive between desired destinations. Even with increasing technological development on the engine efficiency, mileage and fuel economy, passenger comfort is an equally significant factor. Car users look for less fatigue and painless comfort in the long run and this is one of the major issues that is been in the forefront of the automobile manufacturers. It has been identified that vibration caused in the vehicle due to road excitation in addition to the engine. The vibrations excited by the uneven roads are a major factor considered to be a disturbance in the occupants’ seats. This project is to design a model of a car seat and analyze the behavior due to road excitation forces caused as a result of road irregularities. The analysis is to be carried over with the present design of a car seat and modifications in the frame and seat component are to be suggested based on the results. The safety factor of the occupant with reference to the seat is also to be analyzed.

Application of mismatch equations in dynamic seating designs

Anthropometry is critical for product and workplace design. Highly prevalent, office work is associated with sedentarism and physical discomfort due to prolonged sitting. Dynamic seating (alternating across sitting, perching, and standing) has been suggested as an alternative to overcome those problems. The current study tested a large sample of anthropometric data for mismatch levels against national and international office furniture standards using dynamic seating as a framework with traditional and perching mismatch equations, applied to three recommended dynamic seating components. Dimensions present in the standards used did not match the majority of the sample. For sitting, seat width and depth individually presented the lowest levels of match, as well as under cumulative fit of all office furniture dimensions. However, these were alleviated when incorporating adjustability. Perching was shown to be generally impeded given commercially-available chair height options. Limitations in state-of-the-art perching equations are discussed, and two new models are proposed as design alternatives. Further research should focus on testing the criteria presented in this research through discomfort and objective measures.

Design of assembly tools at woodworking and upholstery workstations with PUGH’s Method to improve productivity

This study is a research on manufacturing processes field, especially in the assembly process with a single workstation. This research was conducted on the implementation of manufacturing process of making lecture chairs at the Industrial Engineering Department at Sebelas Maret University. In this research, an assembly tool was designed to solve the problem of high time needed to complete the assembly process of the backrest and cushion seat components and work stations that are not ergonomic. The assembly tool design stages are based on a structured approach of Ulrich and Eppinger (2015) so that it’s good to develop new products and concept selection using the PUGH method to find out the concepts with the highest ranking and best fit the design criteria. This research involved 3 stakeholders, namely operator, lecturer, and assistant. The alternative concept chosen using components are pull-push toggle clamp, gas spring, M6 bolt, multiplex, cam buckle tie down, self-aligning ball bearings, aluminum extrusion 3030. Data on work productivity were tested with Paired T-Test at a significance level of 5 percent. The results showed that by using an ergonomic assembly tool design on woodworking and upholstery workstations, assembly cycle time increased significantly by 63.78 percent.

A system to measure seat-human interaction parameters which might be comfort relevant

In this paper a measurement tool is described and tested to evaluate the characteristics of different elements of a seat. Many studies report a relationship between discomfort and pressure distribution, but it is unknown what exactly is happening in the interaction. The purpose of this study is to present a measuring device, which records the comfort relevant seat parameters pressure and elongation while loading a seat. The results of the study, including the repeatability, reproducibility and detectability show that the measurement method is appropriate for our purpose, although the reproducibility has to be improved by operator experience or by a more intuitive assembling of the measurement setup. An application example illustrates that the interaction of the seat components highly affect the resulting comfort relevant parameters. The question is whether this objectively recorded differences are also experienced by seat occupants, which is interesting to study in future research.

Research on Automatic Detection Method of Minor Faults in Electrical Components of Ejection Seat

In order to solve the problems of high error rate and poor efficiency existing in the current ejection seat electrical fault detection process, the automatic detection method of ejection seat electrical component minor faults was studied, and the original features of component minor faults were effectively extracted with ant colony algorithm as component fault diagnosis comparison data. Combined with the minimum binary algorithm, the safe operation parameters of seat electrical components are calculated. Combined with the safe operation parameters, the mini-fault diagnostic device of ejection seat electrical components is constructed, and the original feature parameters of mini-faults of components are input into the underlying database of the diagnostic device. Once the operating parameters of seat components exceed the range of safety parameters, the original feature data of mini-faults in the database are extracted to screen and detect the mini-faults of seat, so as to quickly obtain the cause of the faults and complete the automatic detection of mini-faults of ejection seat electrical components. Finally, experiments show that the error rate of this method is reduced by more than 50 % compared with the traditional component fault location detection method, which fully meets the research requirements.

A study validating the Italian version of the Level of Sitting Scale in children with cerebral palsy

Objectives: To assess measurement properties of the Italian version of the Level of Sitting Scale when classifying sitting ability of children with cerebral palsy. Design: Methodological study. Setting: Children’s hospital (inpatients and outpatients). Subjects: Children 18 years of age or younger with cerebral palsy. Methods: The original English version of the Level of Sitting Scale was translated and culturally adapted for the Italian culture following international guidelines. Examination of reliability and validity of the Italian Level of Sitting Scale was then undertaken. Inter-rater and one-week test–retest reliability were estimated using both intraclass correlation coefficients (ICCs) with 95% confidence intervals and Bland–Altman plots. Construct validity of the Italian Level of Sitting was evaluated using three approaches examining Pearson’s correlation coefficient (r) and Mann–Whitney U test (P-value < 0.05). Main measures: Italian Level of Sitting Scale and Gross Motor Function Classification System. Results: The Italian Level of Sitting Scale was administered to 109 subjects. Inter-rater reliability and one-week test–retest showed excellent value with ICCs of 0.99 for both. (1) The Pearson correlation coefficient comparing Italian Level of Sitting Scale with Gross Motor Function Classification System was −0.91 and (2) correlation with total amount of adaptive seating components was −0.90. Differences in sitting abilities and use/non-use of wheelchair were found. All reported a statistical significance of P < 0.01. Conclusion: Our findings provide evidence of reliability and validity when using the Italian Level of Sitting Scale to classify seated postural abilities in a sample of Italian children with cerebral palsy.

Modelowanie ciała człowieka na potrzeby projektowania inżynierskiego

The paper presents the method of human body modeling in order to perform the FEM simulation of pressure distributions on the seat components. A CAD model was developed, taking into account internal anatomical features. As a human position, the system was based on the support of the chest, buttocks and shins.

Conceptual Thinking in Design Studios: Upon Music and form Relation

In today’s ever-changing and ever-growing world, new teaching and learning strategies are the focus of attention in order to develop creative thinking in design training. Previous applications of imaginative and formal methods are being evaluated to see their inadequacies, and new approaches are being discussed. Both imagination and form- based approaches are employed to develop creative thinking. Whereas imagination based approaches develop students’ creative thinking, form based ones let them have three dimensional thinking and develop their skills of form creation. In this regard, abstraction- based design studies, which depend upon imagination and concept, are often used to develop students’ form creation skills. Several abstract and concrete different disciplines are starting points in design studios, which enrich students’ imagination and help them develop thinking skills. Music was employed as a source of inspiration in form production using conceptual abstraction within this studio study which resulted from imaginative and formal interaction. In spring semester, 2014-2015 academic year, elective courses such as Creative Thinking and Seat Component, carried out by fellow teaching staff, appear in syllabus of Interior Architecture Department, KTU, and course content and outcomes of studio studies are to be scrutinized within this framework.

High temperature fretting wear prediction of exhaust valve material

IC Engine valve components are generally made from Nickel based (Nimonic-80A) super alloys and these components are exposed to severe operating conditions while the engine is running. Interface fretting combined with impact wear causes major wear related failures to the valve and seat components. There is a need to predict wear of such interfaces so that their life and residual life (i.e. inspection) can be assessed. This paper focusses on a fretting wear of Nimonic-80A material line contact (cylinder-on-flat) at both room temperature and at high temperature conditions. The objective of this study is also to be able to understand the effect of interface fretting displacement, which is the key parameter that controls wear. Tests were performed at three different displacement amplitudes at room temperature (RT) and at high temperature (620°C) for 25,000 cycles. Experimental constants such as wear coefficient (k) and friction coefficient (µ) were derived from the test results. The wear and friction coefficients were then used in the wear-model to predict the wear depth. Further, this model was used to predict wear at 100,000 cycles. Predicted results are compared then with results from tests which have been run beyond 25,000 cycles (i.e. 100,000 cycles).

Natural Frequency Analysis of Automobile Seat

paper, analysis of automobile seat for natural frequency is presented. The IGES model of automobile seat is analyzed on HyperMesh and post processing is done by using NASTRAN solver. All the pre-processing steps are described in details. In pre-processing automobile seat components are meshed with quads and tria elements and solid components are meshed with hex element. Analysis is conducted for free vibration by considering each component separately. Only a fundamental natural frequency is considered in the analysis of critical components. Keywordsnatural frequency, finite element analysis, free vibration.

Numerical prediction of the viscoelastic deformation of seat foam in response to long-term driving

The aim of this paper is to carry out a quantitative evaluation of the time-dependent mechanical characteristics of seat foam and to suggest a process for predicting the viscoelastic deformation of the seat assembly in response to long-term driving. Several tests were conducted to obtain the mechanical properties of the seat components, and the test data were applied in the construction of the material models of the foam pad, the slab foam and the seat cover. An explicit solver (PAM-COMFORT® from ESI) was used to analyse and construct the seat assembly model, and we assumed that the time-dependent behaviour of the seat foam is based on degradation of the material. To describe the behaviour, we used time-dependent stress–strain relationships to account for the viscoelastic characteristics of the seat foam to enable the PAM-COMFORT solver to be used. On multiplying the normalized relaxation modulus by the stress–strain relation, the time-dependent stress–strain relationships can be obtained. In this approach, the material modelling is not a direct method to describe the viscoelasticity using a built-in material model in the commercial program. In order to verify the process, an indenter was used to apply a compressive load to the seat, and the time dependences of the applied load and the deformation were measured experimentally and compared with the results of the numerical analysis. There was good agreement between the experimental results and the numerical analysis results.

Development of Sketch-Based 3-D Modeling System for Rapid Generation and Evaluation of Automotive Seat Shape Using Reference Models

Seat style designers transform their ideas into 3-D forms using creative, iterative modeling processes to quickly evolve their designs from concept to reality, while refining the design details of the seat shape. Although the recent introduction of computer-aided styling systems to the design process has greatly enhanced designers' productivity, they still prefer to ideate using “pen and paper.” Here, we propose a sketch-based 3-D modeling system that enables designers to rapidly and intuitively create a seat shape by applying a 2-D sketch to a normalized seat reference model and then evaluating the newly designed model. For this purpose, we describe three modeling techniques that support interactive shape editing: curve manipulation using pen strokes, vertex point manipulation, and tangent vector manipulation. In addition, we propose three methods for the design and functional evaluation of an automotive seat, checking for interference between a seat skin and its frame, checking for foldability among seat components with regard to their positioning, and checking for coupling between a seat model and a digital human body.

Soft tissue human thigh and buttock finite element model to simulate vehicle seat cushion indentation

Accurate modelling of automotive occupant posture is strongly related to the mechanical interaction between human body soft tissue and flexible seat components. This paper presents a finite-element study simulating the deflection of seat cushion foam and supportive seat structures, as well as human buttock and thigh soft tissue when seated. The thigh-buttock surface shell model was based on 95th percentile male subject scan data and made of two layers, covering thin to moderate thigh and buttock proportions. To replicate the effects of skin and fat, the neoprene rubber layer was modelled as a hyperelastic material with viscoelastic behaviour. The analytical seat model is based on a Ford production seat. The result of the finite-element indentation simulation is compared to a previous simulation of an indentation with a hard shell human model of equal geometry, and to the physical indentation result. We conclude that SAE composite buttock form and human-seat indentation of a suspended seat cushion can be validly simulated.

Postural Stability of Sitting Women

The study examined the utility of stabilometric dimensions and explored whether the changes in sitting postures were manifested in functional measures of postural control. Eleven women participated in the study, which used 11 chair sitting postures: arms on laps or arms right angled; armrest at a height of 17, 20 and 23 cm; with or without backrest; slouch or straight back; legs right angled at knees or crossed legs. The backrest and armrest shifted 16.3% of body weight from a seat pan. The characteristics of stabilometric dimensions evaluated the influence of seat components and sitting behaviour on postural balance. The study attempted to evaluate stability and its application in human-seat interface design.