fabric mechanical parameters related to the beauty of

J. Home Econ. Jpn. Vol. 52 No. 3 251-264 (2001)

Fabric Mechanical Parameters Related to the Beauty of

Fabric Movement of Ladies' Garments Brought

about by Human Motion

Masae NAKANISHI and Masako NIWA*

Department of Home Economics, Kobe Women's University, Kobe 654-8585, Japan*

Nara Women's University, Nara 630-8506, Japan

This paper deals with the effect of fabric mechanical parameters on the beauty of fabric movement

of a one-piece dress TAV (total appearance value). A total of 40 female students evaluated the TAV of

randomly-changed loose-fitting dresses on a movable mannequin that simulated walking conditions.

The dresses were one-piece dresses made from 25 kinds of fabric. The mechanical properties of the

fabrics were measured with the KES-FB system under a set of standardized conditions for ladies' thin

dress fabrics. In order to correlate the TAV with the fabric mechanical properties more closely, we

thought that the measurement conditions should be reconsidered to be near the force levels applied to

the fabric of a one-piece dress during a walking condition. Therefore, we also made a trial tester based

on a KES-Labo model to measure the tensile and shear properties. Using this tester, we measured the

tensile property under a lower tensile force than the standardized condition for a KES-FB1, as well as

the shear property in smaller shear deformations under smaller tension applied to the edge of a fabric

specimen that is almost the same level as the fabric weight of a dress. The contributions to the TAV

made by the basic mechanical properties of fabrics, as well as by parameters derived from the basic

mechanical parameters related to clothing appearance, were investigated using multiple regression

analysis. The results show that the tensile property is closely related to the TAV, although the bending

and shearing properties have been mainly discussed in previous research on the beauty of movement

of ladies' dresses. The findings obtained in this study could be applied as a set of basic data for the

selection of fabric materials for making dresses as the designer intended, for the development of new

materials, and so on.

(Received March 31, 2000; Accepted in revised form December 15, 2000)

Keywords: fabric mechanical properties, tensile property, bending property, shearing property, fabric

movement, one-piece dress.

INTRODUCTION

With fabric hand and wearing comfort, the beauty

of the appearance of clothing is one of the most

important factors determining the quality of gar-

ments. This includes the color, pattern and texture of

a fabric surface, the fitness of a garment to the

wearer's body shape, tailoring technique, and the

beautifully-styled silhouette. In addition, especially for

ladies' clothing, the dynamic silhouette of a garment

or fabric's swaying, caused by the wearer's motion or

the wind, also affects the beauty of the appearance of

the clothing. The first prerequisite in making a

garment with a desired silhouette design is that the

fabric used to make it has suitable mechanical

properties for the design. Assuming that ladies'

garments are classified into one of three main groups-tailored , hari (anti-drape), and drape- the authorshave already introduced a method of objectively discriminating the optimum silhouette type of ladies'

garments based on fabric mechanical properties,1) by applying canonical discriminant analysis. Another objective of the method's development is its use in the

quality assessment of ladies' dress fabrics including the beauty of the appearance of clothing, because the classification of fabrics reduces difficulties in fabric

quality assessment. Howcvcr, this method is only for the first stage classification in deciding an optimum silhouette design to achieve a beautiful dress. As

previous research focused on only static silhouettes, it has not been proven if a dress designed based on that method gives a beautiful impression under dynamic

(251) 25

J. Home Econ. Jpn. Vol. 52 No. 3 (2001)

conditions, with the wearer in motion. There are some

papers that deal with the relation between the beauty of the dynamic silhouette of skirts and fabric

properties such as bending and shearing.2)-5) In these studies, either subjective evaluation tests of the dynamic silhouette were conducted using a small number of fabric samples, or the accuracy of the

prediction equation obtained from the experiments was not verified well. Also, the validity of the measurement conditions of the mechanical properties

related to the beauty of the dynamic silhouette was not clear. Therefore, the contribution of the fabric mechanical properties to the beauty of a dynamic

silhouette remains obscure. That is why we planned the following study of a dynamic silhouette.

A total of twenty-five fabric samples are carefully

selected for a wide variety of fabric mechanical

properties related to the silhouette of clothing. One-piece dresses are made from these fabric

samples using the same pattern. A sensory test to evaluate the beauty of the movement of a one-piece dress is conducted by putting a one-piece dress on a movable mannequin to simulate a walking human. First, we conduct a further investigation of the

measurements of fabric mechanical properties that include the tensile and shearing properties under lower load conditions, considering the movement of

garment fabrics due to the wearer's motion. Then, we clarify the contribution of the fabric mechanical

properties related to the dynamic silhouette and develop an objective evaluation method of the beauty of fabric dynamic movement, which is one of the essential performance aspects of high quality cloth-

ing, in order to obtain the basic data for use in the

selection of suitable fabrics.

METHODS

One-piece dresses used in the experiment

The construction of the experimental one-piece dresses was decided to be a very simple style, adding fullness in order to emphasize the fabric's dynamic

movement. The dress patterns we used to make the one-piece dresses are shown in Fig. 1. There are no seams, except the side seams, to minimize the effect

of the seams. The sizes of the patterns are such that

the circumference of the bust line is 104 cm, the circumference of the hemline is 156 cm and the dress length at the center back is 90 cm. The mannequin which was used for the subjective evaluation test with

one of the one-piece dresses was 81 cm at the bust, 58 cm at the waist, and 84 cm at the hip.

A method to discriminate the optimum silhouette design -tailored, hari and drape- based on the first and second canonical variables Z1 and Z2 which were derived as the functions of fabric parameters such as

fabric weight, tensile, shear, and bending properties,1) was used for the selection of the fabric samples for this study. Tailored-type garments are made to fit

smoothly to the curves of the body through the use of darts and overfeed. Hari and drape type garments have a loose fit; gathers, tucks, flare and other

techniques are used to create clothing in which the fabric area is much larger than the surface area of the body. There are, however, major differences

between these two silhouette types. The hari type uses spacing between the body and garment to emphasize the shape of the garment formed by

horizontal projections, and the drape type emphasizes the beauty of a smooth drape formed in the vertical direction by the weight of the supple fabric itself.

Using this method, fabrics are classified into one of the three groups according to the position of the (Z1, Z2) on the Z1-Z2 plot, in which the center of each

group and discriminant boundary line are marked so that the suitable silhouette type for fabrics may be

easily found, as shown in Fig. 2. As the fabric swaying caused by the wearer's motion does not stand out for the tailored silhouette garments, we omitted fabrics

that were determined to be suitable for typical tailored-type garments. That is, we omitted fabrics

plotted near the center of the tailored group and adopted fabrics plotted in the hari and drape zones to cover as wide an area of groups as possible. The (Z1, Z2) of the 25 samples we used for the experiment are

Fig. 1. The patterns for making the one-piece

dresses used in the visual evaluation tests

The dresses were made from the different types of fabrics

listed in Table 1.

26 (252)

Fabric Mechanical Parameters Related to the Beauty of Fabric Movement of Ladies' Garments

plotted in Fig. 2. In Figs. 2 and 3, three different plot symbols are used properly according to the results of the subjective evaluation test for the beauty of the

fabric movement of a one-piece dress, which will be described later in this paper.

Each of the fabric's basic mechanical parameters for the samples was transformed into a normalized

value using the average and standard deviation of the samples used for the discriminant analysis. The values are plotted in Fig. 3 with the distribution of the

mechanical parameters for fabrics that fall within the tailored, hari and drape type silhouette groups. It can

be seen that the range of parameters of the fabrics used for our experiment covers a wide area of the hari and drape zones.

Table 1 shows the details of the fabric samples used

for this study. The samples include not only traditional fabrics using cotton, wool, silk, linen,

polyester, and blends of these, but also recently developed fabrics using fibers of new regenerated cellulose like Tencel, and specialized polyesters like

Shingosen. The fabric samples include a wide variety of fiber types, weave constructions and yarn con-structions. The fabric weight per unit area ranges from 60 to 220 g/m2, and the fabric thickness ranges

from 0.21 to 0.67 mm. The effect of color, pattern and texture of the fabric surface on the subjective evaluation of the beauty of fabric movement may be

possible, more or less; however, such surface

characteristics of the fabric samples were not unified

in this study. Both plain and patterned fabrics with

varied colors are included in the fabric sample group,

but fabrics with large patterns or prominent textures

are excluded.

Measurement of fabric mechanical properties

1. KES-FB system method

Tensile property was measured under a set of "high

sensitivity" conditions which is used for the measure-

ments of ladies' thin dress fabrics, and the shearing

and bending properties were measured under a set of"

standard" conditions with the KES-FB system.6) The

measurement conditions were 293K and 65%RH. The

basic mechanical parameters are shown in Table 2.

2. Tensile property under a low load condition

Tensile properties under a lower force level than

the high sensitivity conditions used with the KES-FB

system are thought to be related to the beauty of

fabric fluttering or swaying, as the fabric is deformed

by the tension caused by the weight of the fabric

Fig. 2. The position of (Z1, Z2) of the fabrics used for making the one-piece dresses

The Z1, Z2 values are the first canonical variate and the second canonical variate for the discrimination of the optimum silhouette type for fabrics.' *, center of each silhouette group; 0, samples with higher scores for the beauty of movement of a one-piece dress TAV (>m+ 1o),△, samples with lower scores for TAV (<m-1σ), □, m-

1σ＜TAV＜m+1σ.

Fig. 3. The range of values of the basic mechanical

properties of the fabric samples used in this

study

The normalized values using the mean and standard

deviation of 125 types of fabric samples which were used

for the derivation of the discriminant equations are plotted

on the horizontal axes. The data ranges (mean•}la) of the

three silhouette groups (-•›-, tailored (n = 43);-•¥-,

hari (n=42); -•¡-, drape (n= 40)) are also plotted on the

chart. •›, samples with higher scores for the beauty of

movement of a one-piece dress TAV (>m+ 1ƒÐ);

samples with lower scores for TAV (<m-1ƒÐ); m-1ƒÐ<

TAV<m+1ƒÐ.

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itself, the wearer's motion, and wind. They may also

be related to the formability of fabrics that affects the

beauty of the silhouette of garments. In this study, the

trial tester shown in Fig. 4 was made by modifying the

KES-Labo model° for measuring the tensile properties

under lower load conditions with higher accuracy

than the KES-FB1. The details of the measurement

conditions and parameters are shown in Table 3. The

measurement conditions were selected in order to

achieve higher accuracy as follows. The maximum

load was set at 10 gf/cm, which is one-fifth the level

used with high-sensitivity conditions for the KES-FB1,

and the tensile speed was 0.05 mm/s. The parameters

derived from the measurements are tensile energy

WT-h and tensile resilience RT-h, distinguishing these

parameters from the corresponding ones measured

under a set of high-sensitivity conditions.

Table 1. Fabric details of the one-piece dresses used for the visual evaluation

tests

Fig. 4. The KES-Labo model tester used for the

measurement of the tensile properties of

fabrics

28 (254)


3. Shear property at a smaller shear angle under

smaller tension conditions

The shear property under a set of standard

conditions using a KES-FB1 is measured under a

constant tension of 10 gf/cm, with a maximum shear

angle of 8 degrees. However, we feel that this

constant tension value is too large as a corresponding

measurement condition of the shear property suppos-

ing a one-piece dress on the walking human body. We

believe that the shear property under a smaller

tension condition that is at almost the same level as

the fabric weight in a one-piece dress is more

appropriate as the mechanical property to correlate

with the beauty of the movement of a loose-fitting

one-piece dress. A trial tester which uses the same

principle of measurement as the KES-Labo model was made for measuring smaller shear force under

smaller tension applied to the fabric samples with

higher accuracy than the KES-FB1. Figure 5 shows

the new tester. The effective sample size is 20 cm in

width and 3.5 cm in length, while the size used with

the KES-FB1 is 20 cm in width and 5 cm in length.

The length is shortened in the new tester to prevent

fabric buckling. The maximum shear angle is also set

at 2 degrees, because the maximum shear angle in

which a fabric can be deformed in plane without

buckling tends to become smaller when the constant

tension applied to the lower edge of the specimen

becomes smaller.

The tension loaded at the lower edge of the

effective area of a specimen is at a constant 0.5 gf/cm,

adjusting the total weight of a hook and the specimen

of the clamped area (1•~20 cm) at 10 g. As the range

of fabric weight per unit area is from 59.6 to 220.3

g/m2 in this study, the constant tension of 0.5 gf/cm

corresponds to the fabric's weight at a length of 84

cm (=0.5/0.00596) to 23 cm (0.5/0.02203). That is, the

shear property is measured under such levels of

tension. The two parameters G-h and 2HG-h shown in

Table 3 are derived from this measurement. Prelimi-

narily, we also measured the fabric shear property

under the tension of the exact weight of the 50 cm

length of each fabric sample. The correlation

coefficients between the two conditions were very

high, that is, 0.990 for the shear rigidity G-h, and 0.997

for the shear hysteresis 2HG-h. Therefore, we selected

the data under a constant tension of 0.5 gf/cm as the

shear parameter in this study to simplify measure-

ment.

Subjective evaluation test for the beauty of the

fabric movement of a one-piece dress

A movable mannequin was constructed to simulate

the condition of a human walking. The simultaneous

movement of the vertical axis and rotation shown in

Fig. 6 is synchronized using a pulse transmitter for a

stepping motor. The movement along the vertical axis

Table 2. Description of the mechanical parameters and KES-FB measurement conditions for ladies'

thin dress fabrics6)

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of 2 cm and the rotation of•}20 degrees periodically

occurs at the cycle of 0.6 s per step, simulating

human walking.

Putting test one-piece dresses on the mannequin in

random order, the judges looked at the one-piece

dresses and evaluated the degree of the beauty of

fabric movement in the bodice according to a

semantic differential scale from -2 (not beautiful) to

+ 2 (beautiful) graduated in 0.2 intervals. The judges

were 40 female students aged from 18 to 34. The test

was conducted in December of 1998.

RESULTS

Result of the subjective evaluation of TAV

We examined the correlation coefficient r between

the average value of a total of 40 judges' evaluations

and the evaluation of each judge. The result of the

confidential test of correlation coefficient showed that

there was no judge whose evaluation did not have a

significant correlation at a 5% level, although the

correlation of only one judge was insignificant at the

1% level (r=0.428). Therefore, we adopted the

average evaluation of all judges as a "Total Appear-

ance Value (TAV)" of the beauty of fabric movement

for the analysis. Table 4 shows the values of the TAV

for each of the samples and also the values of the

standard deviation of the evaluations of all judges

which indicate the inter-individual differences in the

evaluation. The inter-individual difference is con-

sidered to be from 0.38 to 1.01 and the average is

0.72. In addition, the TAV ranges from -1.58 to 1.22.

We omitted the data of sample No.19 from the

analysis data because the TAV of this sample was too

small, deviating more than -2ƒÐ(ƒÐ: standard deviation)

from the mean of the TAV of all samples m.

The relation between the TAV and each of the

basic mechanical parameters of the fabrics

Figures 2 and 3 show the characteristics of the (Z1,

Z2) position for the discrimination of the optimum

silhouette for a fabric and the basic mechanical

Table 3. Description of the parameters of fabrics' tensile and

shearing properties measured with the KES-Labo model

Fig. 5. The KES-Labo model tester used for the

measurement of the shear properties of

fabrics

Fig. 6. The movement of the mannequin used for the visual evaluation test of one-piece dresses (Photograph: Sample 15)

30 (256)


parameters of fabric samples with higher or lower

values of TAV. In Fig. 2, we can see that circles which

indicate fabrics with higher scores for TAV (TAV>m

+1ƒÐ) are plotted in the zone of drape type, and

triangles which indicate fabrics with lower scores for

TAV (TAV<m-1ƒÐ) are plotted in the zone of hari

type. Looking at the plots of the basic mechanical

parameters, the samples with higher scores for TAV

tend to be extensible and elastic judging from the

higher values of EM and RT_ Also, both the shear

rigidity and hysteresis tend to be smaller in the case

of fabric samples with higher scores of TAV.

We measured tensile and shear properties under

the two conditions shown in Tables 2 and 3 to

examine the effect of the maximum load in tensile

tests on the tensile parameters, and the effect of the

tension level and the maximum shear deformation in

shear tests on the shear parameters. Before the

analysis of the TAV in connection with the fabric

mechanical parameters, each correlation between the

corresponding parameters measured under the two

different conditions had to be investigated, because if

there were an extremely high correlation, we could

use only the data measured with the usual KES-FB

without having to measure the tensile or shearing

property with the KES-Labo model. Table 5 shows the

correlation coefficient and the linear relation between

the paired parameters, which were derived from a

total of 50 data items from the measurement of the

warp and weft direction for the 25 samples used for

this study. Although all of the correlation coefficients

between the data sets are significant, there was no

extremely high correlation coefficient exceeding 0.9.

It seems that the measurement conditions influence,

more or less, each value of the parameters.

We investigated the correlation between the TAV

and the basic mechanical parameters, using the data

of the 24 fabric samples, with the exception of sample

No. 19. The correlation coefficient r for each of the

parameters is shown in Table 6. In addition, a

quadratic regression equation was obtained, taking

into consideration the existence of the optimum

range of the parameter for the beauty of fabric

movement. The regression curve and correlation

coefficient R are shown in Fig. 7. The tensile

properties have been rarely introduced as important

properties related to the beauty of the appearance of

loose fitting ladies' garments. However, the tensile

resilience RT-h, measured under a lower force level

with the KES-Labo model is closely related to the TAV,

and it can be seen that the fabrics with higher values

of RT-h tend to have higher TAV. We can also see the

trend that the higher the shearing rigidity G or G-h,

Table 4. The mean of the TAV of 40 subject

evaluations and the standard deviation S.D. n_i for each fabric sample

Table 5. The relation between the tensile and shear

parameters measured under the two differ-

ent conditions shown in Tables 2 and 3

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the lower the TAV. On the other hand, there is no

distinct correlation between the bending rigidity B

and the TAV. Also, the correlation between the fabric

weight W and the TAV is small, although the relation

between the TAV and the combination parameters

including the fabric weight, such as parameters of

bending or shearing stiffness related to fabric drape,

will be presented later in this paper.

Derivation of the TAV from the basic mechanical

parameters of fabrics

First, we obtained some multiple regression equa-

tions for the TAV using a set of parameters for each

of the mechanical property blocks, that is, tensile,

shearing and bending properties as the explanation

variables for the TAV, in order to examine which

property contributes most importantly to the TAV. As

we presented the correlation between the TAV and

each of the basic mechanical parameters in Table 6

and also Fig. 7, we see that the quadratic regression

model could achieve a better correlation with the TAV

than the linear model. Also, each of the mechanical

parameters was thought to show a non-linear

contribution with an optimum range of the parameter.

Therefore, we assumed the next equation which

includes the squared values of each parameter as the

explanative variables of the TAV.

(1)

Where, Co: constant; Ca, C12: regression coefficient;

Xi1, Xi2: normalized value; namely Xi1= (xi-mi1)/σi1, Xi2

=(xi2-mi2)/σi2, xi: values of the mechanical param-

eters; xi2: square of xi; mil, mi2: mean values of xi and

xi2 for the population of 24 fabrics; ƒÐi1, ƒÐi2: standard

deviation of xi, xi2. mil, mi2, ƒÐi1, ƒÐi2 are shown

in Table 7.

Because the shear parameter 2HG5 is a hysteresis

at a larger shear deformation degree of 5 and it

correlates to the shear rigidity G with a high

correlation coefficient of 0.929 in the case of our

samples, the parameter 2HG5 was not used as an

explanative variable in this study. The values of Zi

which is calculated from Eq. (1) using regression

coefficients Cil, Ci2, are plotted in Fig. 8 to represent

the contribution to the TAV made by each normalized

parameter. The multiple correlation coefficients R and

root mean of the square of regression error RMS are

also shown in Fig. 8. It shows that the mechanical

blocks with higher regression accuracy are, first, the

tensile properties measured with both the KES-FB1

and the KES-Labo model, and secondly, the shear

property. From the contribution line Zi to the TAV of

Table 6. The correlation coefficient r between the TAV and basic mechanical param-eters of a fabric (n=24)

log means log10.

Fig. 7. The correlation between the TAV and each of

the fabric basic mechanical parameters when

a quadratic regression method is applied, TAV

= aXi 2 +bXi + c, Xi = (xi - mi)/ƒÐi (R, multiple

coefficient, N= 24)

32 (258)


each of the tensile parameters, in the case of the

measurement with the KES-FB1, the smaller LT and

larger RT make the TAV higher. In the case of the

KES-Labo model measurement under a lower tensile

load than the KES-FB1, the RT-h makes a particularly

high contribution to the increase of the TAV, and the WT-h also contributes to the increase of the TAV.

Secondly, in order to obtain higher regression

accuracy, we applied the stepwise block regression method, which was developed by Kawabata and Niwa, to derive objective evaluation equations for fabrics'

primary-hand values.8) As mentioned above, the tensile block gives the best regression accuracy for the TAV, so we defined yk' (k: fabric sample) as the

first-predicted value of TAVk by the regression equation (step 1). Next, the residuals ek (=TAVk-yk') are regressed with the sets of parameters in the remaining blocks, except the tensile block, and the

regressed values ek' and the first-prediction yk' are then summed to obtain a new prediction value yk"

(=Yki +ek'). By comparing the correlation coefficients between the TAVk and the yk" for each case, the mechanical block with the highest correlation is

selected as the explanation parameters in this step

(step 2). This procedure is continued in the same manner until all the blocks are included (step 3 and step 4), as we use four blocks: tensile, shearing,

bending, along with the fabric weight per unit area. Using this method, we derived the multiple

regression equations separately for both cases in

which the tensile property under a high sensitivity condition with the KES-FB1 is selected as the first explanation block in step 1 and the property under a lower tension load with KES-Labo model is selected.

Table 8 shows the coefficients of regression equations

Table 7. The mean values of mil, mi2 and the standard deviations en , ei2 of

each mechanical parameters xi, xi2' for the population of 24 fabrics

used for the regression for the TAV

Fig. 8. The contribution Zi of each mechanical

parameter to the TAV and the multiple correlation coefficient R, as well as root mean square of errors RMS when Eq.(1) is

applied for the TAV regression using a set of

parameters of each mechanical block

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C0, Ci1, Ci2 and the multiple correlation coefficient R

and regression error RMS. When the tensile property measured with the

KES-FB1 is selected in step 1, as shown in Eq. (I) in

Table 8, the shear property measured with the KES-FB1, not with KES-Labo model, is selected as the second block in step 2, and the multiple correlation R increases to 0.947. The bending property is selected

as the third block in step 3 and the fabric weight is determined to be the 4th block in step 4, although the contributions of these parameters to the TAV are

relatively small. When the tensile property measured with the

KES-Labo model is selected as the first explanation block in step 1, as shown in Eqs. (II) and (III), the bending property is determined to be as the second block in step 2 and the multiple correlation R is 0.949.

The contribution of the bending parameters to the

TAV shows that larger rigidity B and smaller hysteresis 2HB make the TAV higher. This indicates that the fabric movement becomes more beautiful as

the ratio of the hysteresis element to the elastic element of bending becomes smaller. The RMS is 021 until this stage, that is, when the tensile and bending

properties are used for the explanation parameters. The accuracy of the equation may be said to be relatively high, because the inter-individual differ-ences for the TAV is thought to be within the range

from 0.38 to 1.01, which is the range of the standard deviation of all judgements for each of the samples. In

step 3, the shear property measured with the KES-FB1 is selected with R=0.961 as shown in Eq.

(II), and then the weight is selected with R= 0.964 in step 4, although these properties do not significantly

Table 8. The result of the stepwise-block-regression method

using the basic mechanical parameters of fabrics

C0= 0.210.

34 (260)


affect the TAV. If the shear property measured with

the KES-Labo model in place of the KES-FB1 is selected in step 3, Eq. (111) is obtained with almost the same accuracy as Eq. (II).

DISCUSSION

We investigated the relationship between the TAV

of ladies' garments in this study and the parameters

derived from the basic mechanical parameters of

fabrics, related to primary mechanical components

which influence the beauty of men's tailored suit

appearance. Kawabata and Niwa derived a prediction

equation for the beauty of suit appearance using

three primary mechanical components of fabrics-that is

, the formability component, elastic potential

component and drapeability component- by investi-

gating the relationship between fabric mechanical

properties and the beauty of men's tailored suit

appearance.8) Each of the components consists of two

or three parameters derived from the basic mechani-

cal parameters measured with the KES-FB system

under a set of "standard conditions." Although the

measurement conditions of the fabric mechanical

properties used in this study are different from those

for the suiting fabrics, for example in the maximum

force level in the tensile test, we tried to analyze the

TAV using parameters corresponding to the param-

eters used to predict men's suit appearance. As

shown in Table 9, the parameters EL2, BS2 and SS are

selected for the formability component, EP, BP and

SP for the elastic potential component, and BSIW

and 3•ãSS/W for the drapeability component. Also, as we

Table 9. Mechanical parameters related to the beauty of the garment's appearance

-h(e.g., SS-h) means the parameter measured with KES-Labo model in order to distinguish the parameter

fromthecorrespondingonemeasuredwithKES-FB1.

Fig. 9. The correlation between the TAV and each of

the parameters derived from the basic

mechanical parameters of fabrics when a

quadratic regression method is applied, TAV=αXi2+bXi+c, Xi=(xi-mi)/σi

(261) 35


have the mechanical data measured with the KES-

Labo model, the parameters SS-h, EP-h, SP-h

and 3•ãSS/W-h are added.

Firstly, we investigated the relationship between the

TAV and each of the mechanical parameters, applying

the quadratic regression method because each

parameter was thought to have an optimum value in

the same way as the basic mechanical parameters.

Figure 9 shows the regression curve and correlation

coefficient. As for the parameters related to the

formability of a garment, we can see that the TAV

tends to decrease as the effective shearing stiffness

SS or SS-h become larger. As for the elastic potential

component, in particular, as the tensile elastic

potential energy EP-h measured under a lower

tension load with the KES-Labo model increases, the

TAV rises. This indicates that the tensile property

under a lower tension load has a close relation to the

TAV, along with the resilience RT-h, as mentioned

earlier. It may be considered that these tensile elastic

potential parameters are related to the occurrence of

the vibration of the fabric, like spring behavior in a

dynamic condition, which leads to the higher TAV

reflecting the fabric's liveliness and bouncing impres-

sion. On the other hand, fabrics with higher values of

the shearing elastic potential SP or SP-h tend to have

a lower TAV, while the bending elastic potential BP

has nothing to do with the TAV. However, it can be

seen that the TAV tends to decrease as the

parameters related to the drape of fabrics, VBS/W,

which corresponds to "bending length" in a cantilev-

er, become larger. Also, the other drapeability

component parameter, the shearing stiffness related

to drape 3•ãSS/W or 3•ãSS/W-h, is more closely related to

the TAV of ladies' garments, and smaller values are desirable for the TAV.

Secondly, multiple regression analysis was cond-

ucted using the mechanical parameter group of each of the components (formability, elastic potential and drapeability) as explanation parameters. Supposing

that the contribution of each parameter to the TAV has a quadratic form, the square terms of each mechanical value were included as the explanation variables, in the same way as Eq. (1) was applied to

the regression using the basic mechanical parameters of each mechanical property block. Table 10 shows

the multiple correlation coefficients R and the regression errors RMS which resulted from the multiple regression analysis. The highest multiple correlation coefficients R were obtained by the elastic

potential component group by including the EP-h measured under the lower load condition with the KES-Labo model instead of the EP. These results

indicate that the elastic potential component, includ-ing the tensile property under a lower load and

shearing and bending properties, closely relates to the beauty of fabric movement of a loose-fitting one-piece dress.

In this way, we derived the TAV equations using the

parameters of the primary components related to the appearance of garments. However, we would like to recommend Eq. (II), derived by the stepwise block

regression method using the basic mechanical

parameters, as the prediction equation of the TAV, because Eq. (II) has a higher regression accuracy

and is also preferable from the viewpoint of fabric design. One reason for this is that all of the

parameters are the fabrics' basic mechanical param-

Table 10. The results of the multiple regression using the

parameter group of each of the components:

formability, elastic potential and drapeability

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eters which are linked to the engineered textile material design from fibers to fabrics through yarns.

Another reason is that the order of importance of each property block for the TAV is clarified and

therefore the TAV can be predicted using only the effective properties of the first block (tensile) or the

first block and the second block (bending) with relatively high accuracy. Thus, it is indicated that Eq.

(II) is easier to use and also more applicable to actual fabric design for creating beautiful clothing silhouettes under dynamic conditions.

CONCLUSION

The mechanical properties of fabrics related to the

beauty of fabric movement of a loose-fitting one-piece dress TAV brought about by human motion and also

the measurement conditions of tensile and shear

properties were discussed in this paper. It was found that the TAV is closely related to the tensile property, especially under a lower tensile load, although the tensile property has not been regarded as an

important property until now. In our experiment, the tensile property under a lower tension load (ma-ximum load= 10 gf/cm) is more closely related to the

TAV than the tensile property measured under a set of high sensitivity conditions with the KES-FB1, which is used all over the world for the objective evaluation of fabric hand.

The regression equation of the TAV, Eq. (II) in Table 8, was obtained with higher regression accuracy

by the stepwise block regression method using the basic mechanical parameters of tensile, bending, shearing and fabric weight. Also, multi-variable regression analysis was conducted for each of the

three primary mechanical components related to the beauty of garment appearance. The results were that the elastic potential component predicted the TAV

with higher accuracy than the formability and drapeability component, and the elastic potential of fabric was thought to be more important for the

beauty of the movement of loose-fitting one-piece dresses.

At present, we conclude that Eq. (II) is the most

preferable TAV prediction equation, but in future

studies, we would like to inspect the prediction ability

of the equation by applying new fabric samples that were not used to derive the equation.

REFERENCES

1) Niwa, M., Nakanishi, M., Ayada, M., and Kawabata, S.: Optimum Silhouette Design for Ladies' Garments Based on the Mechanical Properties of a Fabric, Textile Res. J., 68 (8), 578-588 (1998)

2) Ayada, M., and Niwa, M.: Relation between the Comfort of Gathered Skirts and the Fabric Mechanical Proper-ties (in Japanese), Sen-i Gakkaishi, 47 (6), 291-298

(1991) 3) Izumi, K., and Niwa, M.: Evaluation of Dynamic Drape

of Ladies' Dress Fabrics, in Proceedings of the 3rd Japan-Australia Symposium on Objective Measurement: Applications to Product Design and Process Control, Kyoto, Textile, Machinery Society of Japan, Osaka, 725-734

(1986) 4) Matsudaira, M.: Vibrational Property of Filament Weave

Based on Shear Deformation Part 3: Relationship between Shear and Bending Vibrational Properties of Fabrics and Beautiful Appearance of Skirts in Dynamic State (in Japanese), Nihon Seni Kikai Gakkaishi (J. Textile Machin. Soc. Jpn.), 45 (8), T115-T121 (1992)

5) Matsudaira, M.: Relationship between Vibrational Prop-erty of Shingosen Polyester Fabrics and Beautiful Appearance of Moving Skirt (in Japanese), Kanazawa Daigaku Kyoikugakubu Kiyou Shizenkagakuhen (Bull. Fac. Educ. Kanazawa Univ. Nat. Sci.), No. 43,39-47 (1994)

6) Kawabata, S., and Niwa, M.: Improvement in the Objective Evaluation of Fabric Hand for Thin Dress Fabrics, Part 1: Selection of the Fabric Deformation Range in the Measurement of Mechanical Properties

(in Japanese), Nihon Seni Kikai Gakkaishi (J. Textile Machin. Soc. Jpn.), 37 (7), T113-T121 (1984)

7) Kawabata, S., and Niwa, M.: Jikkenshitsu de dekiru tezukuri souchi wo mochiita yasashii nuno no rikigakutokusei no keisoku to kenkyuu no tenkai, Kiso toshiteno yasashii ifukuzairyou koushuukai koumokubetsu siriizu, yasashii nuno no rikigaku to fuuai, Textile Machin. Soc. Jpn. HESC, Osaka, 23-36 (1978)

8) Kawabata, S., and Niwa, M., Fabric Performance in Clothing and Clothing Manufacture, J. Text. Inst., 80 (10), 19-50 (1989)

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婦人服の着用動作による布の動きの美しさに関わる布の力学パラメータ

中西正恵,　丹羽雅子*

(神戸女子大学家政学科,*奈良女子大学)

原稿受付平成12年3月31日;原稿受理平成12年12月15日

本論文では,ワンピースドレスの布の動きの美しさZ4V(total　 appearance　 value)に及ぼす

布の力学パラメータの影響を紹介する.歩行を模擬する動くマネキンに25種の布でつくった

ルーズなワンピースをランダムに着せ替えていって,40人の女子学生がTAVを評価した.布

の力学特性を,KES-FBシステムにより婦人薄手布用の標準化された条件で測定した.より密

接にTAVを布の力学特性と結び合わせるためには,測定条件を歩行中のドレスの布にかかる

カレベルに近づけるよう見直すべきと考え,我々は,引張り.せん断測定用のKES-Labo

modelを原型とした新しい測定装置を試作した.この装置を用いて,KES-FB1の条件よりも

小さいカレベルでの引張り特性,および,布に負荷する一定引張り荷重を着用時の布の自重と

ほぼ等価のより小さい値とし,微小せん断ひずみ領域でのせん断特性を測定した.布の基本力

学特性,衣服の外観に関わる基本力学特性値から誘導されるパラメータのTAVへの寄与が,

重回帰分析により調べられた.これまでの婦人服の動きの美しさについての研究では,曲げと

せん断特性が主として議論されてきたが,TAVには布の引張り特性も密接に関連していること

が示された.本研究での知見は,イメージした服づくりのための布の選別や新素材の開発など

に応用できるだろう.

キーワ-ド:布の力学的性質,引張り特性,曲げ特性,せん断特性,布の動き,ワンピースド

レス.

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fabric mechanical parameters related to the beauty of

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