Touch Feel and Appearance Characteristics of Automotive Door Armrest Materials 2007-01-1217

This paper presents results of a five phase study conducted to evaluate touch feel and appearance of door armrest materials. Seven different production door armrests with different material characteristics such as softness, smoothness, compressibility, texture, etc. were evaluated. In the first phase, the subjects seated in a vehicle buck in their preferred seating position with the armrests adjusted at their preferred heights, provided ratings on a number of touch feel and appearance of the door armrest materials using 5-point semantic differential scales. In the second phase, the armrests were presented to each subject in all possible pairs and they were asked to select preferred armrest material in each pair. In the third phase, pressures in the armrest contact area were measured in three armrest usage postures, namely: i) lower arm supported on the armrest (not holding the steering wheel), ii) elbow resting on the armrest while grasping the steering wheel, and iii) the subject attempting to reposition in the seat while pushing his/her elbow against the armrest (maximum possible pressure). Pressure measurements (peak, average and contact area) were made for 12 subjects using XSENSOR pressure mapping digital mat. The fourth phase involved evaluation of all the touch characteristics in the dark to eliminate any visual influence. And finally, in the fifth phase, the subjects were asked to rank order important characteristics of the armrest materials.

Some results of the studies are: a) The 95% confidence intervals of 5-point ratings discriminated different armrests on each characteristic defined by adjective pairs such as Smooth/Rough, Compressive/Non-Compressive, Plain/Textured, Fine/Coarse, etc. b) Correlation analyses revealed a number of relationships between the variables (e.g. Soft/Hard ratings were highly correlated with Compressive/Non-Compressive ratings, Cheap/Expensive ratings were correlated to Fake/Genuine, and Pleasing/Non-Pleasing ratings; but Texture/Plain were uncorrelated with Cheap/Expensive or Fake/Genuine ratings). c) The pressure measurements data showed: i) Under normal forearm resting posture the average and peak pressures ranged between 3 to 10 psi and 4 to 25 psi, respectively. ii) With the elbow resting on the armrest while holding on the steering wheel, the average and peak pressures ranged between 4 to 19 psi and 5 to 40 psi, respectively. iii) While repositioning in the seat, the average and peak pressures ranged between 5 to 17 psi and 10 to 40 psi, respectively. d) Evaluations of touch feel conducted in the dark, differed from those from those conducted using both touch and visual sensory cues.