DESIGN PARAMETERS OF

SEAT

FIT PARAMETER

FEEL PARAMETER

SUPPORT PARAMETER

FIT PARAMETERS Cushion width

Cushion length

Backrest Width

Backrest Height

RECOMMENDED FIT PARAMETERS

Parameter Minimum (mm)

Maximum (mm)

Cushion width

• actual width at H point 432

• clearance at H point 500

• width at front of cushion 500

Cushion length

• forward of H point on thigh line

305

Backrest width

• at waist (220 mm above H point)

360

• at chest (318 mm above H point

456

Backrest height 410 550

SCHEMATIC REPRESENTATION

OF FIT PARAMETER

CUSHION LENGTH

FEEL PARAMETERS Pressure

Shear stress

Temperature

Humidity

Pressure

Body tissues can readily tolerate up to 240 psi (12400 mm Hg).

Temperature and humidity:

Heat flux :The total heat flux through the seat,

including heat transfer due to evaporation, should be

about 75 W/m2.

Material :Perforated cover materials are desirable

because of reduced resistance to water vapour

diffusion.

SUPPORT PARAMETERS Lumbar Support

Body Segment Angles and Seat Adjustments

Knee Angle

Trunk/Thigh Angle

Lumbar SupportMethodologies :

Anthropometry

Electromyography

Reynolds (1993) model of linkage representations of the human body:

CASE STUDY OF CAR-SEAT

DESIGN

Three seats were chosen based on their difference in design and on the car model :

one seat with steep wings used in sportive cars

one seat that is less contoured used in luxurious cars

and a new seat concept based on the human body contour developed at BMW.

NEW CAR-SEAT CONCEPT BASED ON THE HUMAN BODY CONTOUR DEVELOPED AT BMW (FRANZ ET AL.)

METHODOLOGY OBJECTIVE RESEARCH:

To define the shape and contour of all three seats, the following aspects where measured:

WIDTH OF SEAT AND BACKREST

STEEPNESS OF BACK- AND SEAT WINGS

CONTOUR OF BACKREST

The hardness of the seat cushion, based on the thickness of the foam material and hardness in kPa.

SUBJECTIVE RESEARCH PARTICIPANTS: 21 participants. Their mean height was 1.78 (1.63e1.92)

m and their mean weight was 76 (48e107) kg.

SEATS: All have the same backrest angle (25°) .

SET-UP: All seats were covered with a thin blanket. Emocard method was applied. All seats were tested for approximately 5 min.

THE 16 EMOCARD PLACED ON RUSSELL’S

CIRCUMPLEX OF EMOTIONS.

DIMENSIONS OF SEAT UNDER

OBSERVATION

Seat width(cm)

Seat wing(°)

Contour 1 50-31 51

Contour 2 48-29 35

Contour 3 52-52 No wings

Backrest width(cm)

Backrest wing(°)

Contour 1 49-31 60

Contour 2 51-27 47

Contour 3 50-50 No wings

OVERVIEW OF MENTIONED

SEAT CONTOURS

RESULTS

The Emocard chosen by 71% of the participants shows a pleasant emotion, but medium level of arousal.

The most important findings are that hard seats with rather high side supports are rated sporty, seats that are softer are rated more luxurious.

The intensity of the color indicates the level of arousal (the darkest shade is the highest arousal). The most positive overall emotions are elicited by seat contour 1 (86%), followed by contour 2 (76%) and contour 3 (52%).

REFERENCES Irene Kamp

Faculty of Industrial Design Engineering, Delft University of Technology, Landbergstraat 15, 2628 CE Delft, The Netherlands.

The influence of car-seat design on its character experience

Matthew P. Reed, Lawrence W. Schneider,Leda L. Ricci University of Michigan Transportation Research Institute

Survey of auto seat design recommendations for improved comfort

Broman, H., Pope, M. H., Benda, M., Svensson, M., Ottosson, C., and Hansson, T. (1991, January).

The impact response of the seated subject. Journal of Orthopaedic Research.

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