57th International Convention of Society of Wood Science and Technology
June 23-27, 2014 - Zvolen, SLOVAKIA
TACTILE INTERACTION AND CONTACT
COMFORT OF WOOD AND WOOD
MATERIALS
Veronika Kotradyova
Faculty of Architecture STU Bratislava, Slovakia
Alfred Teischinger
Institute of Institute of Wood Science and Technology, BOKU Vienna, Austria
Project
INTERACTION OF HUMAN AND WOOD
since 2011
Intraction of human and its built environemnt, namely wood
complex understanding = whole picture understanding
Visual/aesthetic performance of wood
Tactile interaction (contact comfort)
Acoustic interaction
Olfactory and gustatory interaction
Socio-cultural background
Human = cultural creature
Human = animal
versus
cortex
reptilian brain
Body cosscious design / Human centered design /Neuroergonomy
DESIGNING FROM INSIDE OUT
TACTILE INTERACTION and CONTACT COMFORT
by hand
by whole skin
and entire body
Term contact comfort was first time used by Harry Harlow – American
psychologist, in relation to maternal-separation, dependency needs, and social
isolation experiments on rhesus monkey (published in study "The Nature of
Love„)
Harlow shown by it the importance of care-giving and companionship in social
and cognitive development.
CLOTHING
Breathability and clothing comfort. Simulating differing environments
Thermal and sweating manikin for comfort assessment
The most common clothing
comfort related sensory attributes
are thermal, moisture, tactile, hand
and aesthetic experiences.
Assessing the complexity of “contact comfort” of a person
touching a material, we suggest the following parameters or
indicators for expressing the CONTACT COMFORT:
1. thermal comfort related to thermal conductivity, effusivity
and thermal contact conductance of the surface
2. roughness of the surface
3. hardness of the surface including the elasticity of the
supporting material layer
4. sorption activity of the surface in terms of absorbing the
external moisture (e.g. sweat or humidity of air/its
condensates)
5. having control over the body position (e.g. in the case of a
seat shell)
6. possibilities of maintenance connected with cultural
background of users
7. individual mental and physical setting that influence an
overall feeling of comfort.
Average subjective rating
vs
objective measurable parameters
List of related measurable parameters linked with indicators of
contact comfort , together with attitude towards contact comfort
Indicators of contact
comfort
MEASURABLE
PARAMETERS
Unit
THERMAL COMFORT
Thermal conductivity (λ)
Increasing(+) or
decreasing (-)
attitude of the
variable towards
(or in relation) to
contact comfort
W/mK
-
m2/s
-
ROUGHNESS
HARDNESS
SORPTION ABILITIES
thermal
effusivity/diffusivity (a)
Thermal contact
conductance (hc)
Roughness (Ra)
Brinell hardness (HB)
Water sorption
coefficient (A)
Apparent moisture
diffusivity (K)
Diffusion coefficient (D(u)
-
μm
N/mm²
kg.m-2.s-1/2
+
+
m2/s
+
m2/s
+
or De)
Water vapor diffusion
resistance coefficient
(μ)
Water vapour diffusion
permeability (σ)
-
S
+
Average subjective rating (ASR) of the contact comfort
Testing chair with exchangeable sets of seat, arm rests and backrests, arm rest are also
usable for testing the edge radius preferences.
The following test materials were used:
1.polypropylene
2.aluminium
3. thin plywood board set with PUR-lacquer finishinghigh glance
4. beech glued board set with PUR-lacquer finishing high glance
5. beech glued board set with flax oil finishing
6. beech glued board set without finishing
7.spruce glued board set with PUR-lacquer finishing high glance (focus to “sliding effect”)
8.spruce glued board set with flax oil finishing
9. spruce glued board set without finishing
In second extended phase of the tests three more
materials were added (tested with respondents in
Slovakia only).
10. WPC (Wood Plastic Composites)
11. Plexiglas
12. Cork
2 milestones
I. Evaluation after immediate
reaction
II. Rating after 10 minutes of
sitting
Results – assessment of contact comfort
Thermal comfort and roughness of surface
are closely related to each other.
The rougher the surface, the better thermal
comfort is felt thanks to the presence of air
in the contact zone between the body and
a material
Roughness is a strategic feature also for all other parameters.
Relation of roughness of surface and other indicators of contact comfort and
partly also somatic comfort and socio-cultural comfort. Sign „+“ means that it
has positive influence and sign „-“ means negative influence
Other indicators of contact ROUGH SURFACE versus
comfort
SMOOTH SURFACE
(up to polished)
THERMAL COMFORT
+
↔
-
HARDNESS
-
↔
+
SORPTION ABILITY
+
↔
-
HAVING CONTROL OVER
SITTING POSSITION/
somatic comfort
+
↔
-
POSSIBILITIES OF
MAINTANANCE /
socio-cultural comfort
-+
↔
+-
Tactile interraction and contact comfort are the main indicator of the
SURFACE AUTHENTICITY
Schattdecor – producer of coating folias and their collection „Industrial heritage“
The truth is the best material…
Wolfgang Haipl
possibilities of maintenance
connected with cultural background of users
Without finishing, fihishing with oil and laquered finishing, www.adler.sk
Perfect maintenance –
lack of tactile authenticity
Contact of human body with different sorts of surfaces
Comparison of subjectively expressed rating of indicators of contact comfort with
measurable parameters by single materials. Average subjective rating (ASR) and objective
parameter from reference (OPR)
Materials
Polypropylene
Thermal comfort
ASR
cold / warm
3,7
OPR
thermal
conductivity λ
[W/(m*K)]
Optimal roughness
0,22
ASR
for property
smooth /
rough
2,1
Hardness
Sorption abilities
OPR
RoughASR
ness
for
Average Ra property
OPR
[μm]
hard / soft HB [N/mm²]
3,2
70
ASR
for property
wet / dry
4,2
OPR Absorption
coefficient
µ [cm2/g]
10000
Aluminum
beech plywood (5mm
thick) lacquered
solid beech glued board
(25mm thick) lacquered
solid beech glued board
(25mm thick) oiled
solid beech glued board
(25mm thick) raw
solid spruce glued
board (18 mm thick)
lacquered
solid spruce glued
board (18 mm thick)
oiled
solid spruce glued
board (18 mm thick)
raw
1,5
200
2,2
2,9
80
4,0
∞
4,9
0,17
3,2
4,5
-
4,5
67-72
5,0
[4]
2,3
4,8
33
4,1
2000-40000* [2]
5,9
[4]
5,2
4,9
-
5,8
-
5,7
0,20 [´1]
5,1
4,5
34
5,5
6,3
[1]
2,6
4,1
12
5,5
2000-40000 [2]
7,0
[1]
4,3
5,8
-
6,1
-
7,4
0,15 [1]
5,5
5,9
15,6
6,7
50/400
WPC (22mm thick)
3,5
0,24
4,4
28
4,9
plexiglass, (8mm thick)
2,5
0,18
3,1
2,7
180-200
4,8
50000
cork raw (8mm thick)
8,3
0,045
5,6
6,6
7,0
5-10
[1]
0,8
7
50/400
There were not found particular values for the different surface finishing of spruce and beech
PVC paint has absorption coefficient µ 2000-10000 cm2/g and by water Water-thinnable clear varnish it is 2500-10000 cm2/g
and by epoxid paints it is 10000-40000 cm2/g
[2]
Results
- There is a relation between subjectively expressed rating of
indicators of contact comfort with measurable parameters
by single materials.
- for most of the assessment criterions: wood provides
more comfort than plastic , WPC or aluminium
- there are difference between the two wood species
tested (e.g. hard/soft – hardwood/softwood)
- there are slight differences between laquered and oiled
surfaces , but there is a more significant difference with
raw materials
- control over body position is an important criterion and
it is strongly related to surface roughness (an appropriate
surface roughness can be achieved with every material)
- after 10 minutes only a few criterions show significant
changes in the scores – a longer time span is necessary
test of subjective preferences would be then even more
time demanging
Future research of tactile interaction of
human and wood
- to define and deepend the linkage
between subjectively felt characteristics
and objectively measurable parameters
- measurements of missing parameters
important for the different kind of
comfort (with focus on contact comfort),
especially for the different surface
finishing of materials.
- to set a methodics for evaluating the
contact comfort that is less time
demanding , subjective and objective in
the same time
- to create an interactive instrument for
evaluation the human-friendliness of
materials
Thank you for your attention…
[email protected]
[email protected]
www.bcdlab.eu